001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018 package org.apache.commons.pool.impl;
019
020 import java.util.ArrayList;
021 import java.util.Collection;
022 import java.util.HashMap;
023 import java.util.Iterator;
024 import java.util.LinkedList;
025 import java.util.List;
026 import java.util.Map;
027 import java.util.NoSuchElementException;
028 import java.util.Set;
029 import java.util.TreeMap;
030 import java.util.TimerTask;
031
032 import org.apache.commons.pool.BaseKeyedObjectPool;
033 import org.apache.commons.pool.KeyedObjectPool;
034 import org.apache.commons.pool.KeyedPoolableObjectFactory;
035
036 /**
037 * A configurable <code>KeyedObjectPool</code> implementation.
038 * <p>
039 * When coupled with the appropriate {@link KeyedPoolableObjectFactory},
040 * <code>GenericKeyedObjectPool</code> provides robust pooling functionality for
041 * keyed objects. A <code>GenericKeyedObjectPool</code> can be viewed as a map
042 * of pools, keyed on the (unique) key values provided to the
043 * {@link #preparePool preparePool}, {@link #addObject addObject} or
044 * {@link #borrowObject borrowObject} methods. Each time a new key value is
045 * provided to one of these methods, a new pool is created under the given key
046 * to be managed by the containing <code>GenericKeyedObjectPool.</code>
047 * </p>
048 * <p>A <code>GenericKeyedObjectPool</code> provides a number of configurable
049 * parameters:</p>
050 * <ul>
051 * <li>
052 * {@link #setMaxActive maxActive} controls the maximum number of objects
053 * (per key) that can allocated by the pool (checked out to client threads,
054 * or idle in the pool) at one time. When non-positive, there is no limit
055 * to the number of objects per key. When {@link #setMaxActive maxActive} is
056 * reached, the keyed pool is said to be exhausted. The default setting for
057 * this parameter is 8.
058 * </li>
059 * <li>
060 * {@link #setMaxTotal maxTotal} sets a global limit on the number of objects
061 * that can be in circulation (active or idle) within the combined set of
062 * pools. When non-positive, there is no limit to the total number of
063 * objects in circulation. When {@link #setMaxTotal maxTotal} is exceeded,
064 * all keyed pools are exhausted. When <code>maxTotal</code> is set to a
065 * positive value and {@link #borrowObject borrowObject} is invoked
066 * when at the limit with no idle instances available, an attempt is made to
067 * create room by clearing the oldest 15% of the elements from the keyed
068 * pools. The default setting for this parameter is -1 (no limit).
069 * </li>
070 * <li>
071 * {@link #setMaxIdle maxIdle} controls the maximum number of objects that can
072 * sit idle in the pool (per key) at any time. When negative, there
073 * is no limit to the number of objects that may be idle per key. The
074 * default setting for this parameter is 8.
075 * </li>
076 * <li>
077 * {@link #setWhenExhaustedAction whenExhaustedAction} specifies the
078 * behavior of the {@link #borrowObject borrowObject} method when a keyed
079 * pool is exhausted:
080 * <ul>
081 * <li>
082 * When {@link #setWhenExhaustedAction whenExhaustedAction} is
083 * {@link #WHEN_EXHAUSTED_FAIL}, {@link #borrowObject borrowObject} will throw
084 * a {@link NoSuchElementException}
085 * </li>
086 * <li>
087 * When {@link #setWhenExhaustedAction whenExhaustedAction} is
088 * {@link #WHEN_EXHAUSTED_GROW}, {@link #borrowObject borrowObject} will create a new
089 * object and return it (essentially making {@link #setMaxActive maxActive}
090 * meaningless.)
091 * </li>
092 * <li>
093 * When {@link #setWhenExhaustedAction whenExhaustedAction}
094 * is {@link #WHEN_EXHAUSTED_BLOCK}, {@link #borrowObject borrowObject} will block
095 * (invoke {@link Object#wait() wait} until a new or idle object is available.
096 * If a positive {@link #setMaxWait maxWait}
097 * value is supplied, the {@link #borrowObject borrowObject} will block for at
098 * most that many milliseconds, after which a {@link NoSuchElementException}
099 * will be thrown. If {@link #setMaxWait maxWait} is non-positive,
100 * the {@link #borrowObject borrowObject} method will block indefinitely.
101 * </li>
102 * </ul>
103 * The default <code>whenExhaustedAction</code> setting is
104 * {@link #WHEN_EXHAUSTED_BLOCK}.
105 * </li>
106 * <li>
107 * When {@link #setTestOnBorrow testOnBorrow} is set, the pool will
108 * attempt to validate each object before it is returned from the
109 * {@link #borrowObject borrowObject} method. (Using the provided factory's
110 * {@link KeyedPoolableObjectFactory#validateObject validateObject} method.)
111 * Objects that fail to validate will be dropped from the pool, and a
112 * different object will be borrowed. The default setting for this parameter
113 * is <code>false.</code>
114 * </li>
115 * <li>
116 * When {@link #setTestOnReturn testOnReturn} is set, the pool will
117 * attempt to validate each object before it is returned to the pool in the
118 * {@link #returnObject returnObject} method. (Using the provided factory's
119 * {@link KeyedPoolableObjectFactory#validateObject validateObject}
120 * method.) Objects that fail to validate will be dropped from the pool.
121 * The default setting for this parameter is <code>false.</code>
122 * </li>
123 * </ul>
124 * <p>
125 * Optionally, one may configure the pool to examine and possibly evict objects
126 * as they sit idle in the pool and to ensure that a minimum number of idle
127 * objects is maintained for each key. This is performed by an
128 * "idle object eviction" thread, which runs asynchronously. Caution should be
129 * used when configuring this optional feature. Eviction runs require an
130 * exclusive synchronization lock on the pool, so if they run too frequently
131 * and / or incur excessive latency when creating, destroying or validating
132 * object instances, performance issues may result. The idle object eviction
133 * thread may be configured using the following attributes:
134 * <ul>
135 * <li>
136 * {@link #setTimeBetweenEvictionRunsMillis timeBetweenEvictionRunsMillis}
137 * indicates how long the eviction thread should sleep before "runs" of examining
138 * idle objects. When non-positive, no eviction thread will be launched. The
139 * default setting for this parameter is -1 (i.e., by default, idle object
140 * eviction is disabled).
141 * </li>
142 * <li>
143 * {@link #setMinEvictableIdleTimeMillis minEvictableIdleTimeMillis}
144 * specifies the minimum amount of time that an object may sit idle in the
145 * pool before it is eligible for eviction due to idle time. When
146 * non-positive, no object will be dropped from the pool due to idle time
147 * alone. This setting has no effect unless
148 * <code>timeBetweenEvictionRunsMillis > 0.</code> The default setting
149 * for this parameter is 30 minutes.
150 * </li>
151 * <li>
152 * {@link #setTestWhileIdle testWhileIdle} indicates whether or not idle
153 * objects should be validated using the factory's
154 * {@link KeyedPoolableObjectFactory#validateObject validateObject} method
155 * during idle object eviction runs. Objects that fail to validate will be
156 * dropped from the pool. This setting has no effect unless
157 * <code>timeBetweenEvictionRunsMillis > 0.</code> The default setting
158 * for this parameter is <code>false.</code>
159 * </li>
160 * <li>
161 * {@link #setMinIdle minIdle} sets a target value for the minimum number of
162 * idle objects (per key) that should always be available. If this parameter
163 * is set to a positive number and
164 * <code>timeBetweenEvictionRunsMillis > 0,</code> each time the idle object
165 * eviction thread runs, it will try to create enough idle instances so that
166 * there will be <code>minIdle</code> idle instances available under each
167 * key. This parameter is also used by {@link #preparePool preparePool}
168 * if <code>true</code> is provided as that method's
169 * <code>populateImmediately</code> parameter. The default setting for this
170 * parameter is 0.
171 * </li>
172 * </ul>
173 * <p>
174 * The pools can be configured to behave as LIFO queues with respect to idle
175 * objects - always returning the most recently used object from the pool,
176 * or as FIFO queues, where borrowObject always returns the oldest object
177 * in the idle object pool.
178 * <ul>
179 * <li>
180 * {@link #setLifo <i>Lifo</i>}
181 * determines whether or not the pools return idle objects in
182 * last-in-first-out order. The default setting for this parameter is
183 * <code>true.</code>
184 * </li>
185 * </ul>
186 * <p>
187 * GenericKeyedObjectPool is not usable without a {@link KeyedPoolableObjectFactory}. A
188 * non-<code>null</code> factory must be provided either as a constructor argument
189 * or via a call to {@link #setFactory setFactory} before the pool is used.
190 * </p>
191 * <p>
192 * Implementation note: To prevent possible deadlocks, care has been taken to
193 * ensure that no call to a factory method will occur within a synchronization
194 * block. See POOL-125 and DBCP-44 for more information.
195 * </p>
196 * @see GenericObjectPool
197 * @author Rodney Waldhoff
198 * @author Dirk Verbeeck
199 * @author Sandy McArthur
200 * @version $Revision: 781288 $ $Date: 2009-06-03 03:52:20 -0400 (Wed, 03 Jun 2009) $
201 * @since Pool 1.0
202 */
203 public class GenericKeyedObjectPool extends BaseKeyedObjectPool implements KeyedObjectPool {
204
205 //--- public constants -------------------------------------------
206
207 /**
208 * A "when exhausted action" type indicating that when the pool is
209 * exhausted (i.e., the maximum number of active objects has
210 * been reached), the {@link #borrowObject}
211 * method should fail, throwing a {@link NoSuchElementException}.
212 * @see #WHEN_EXHAUSTED_BLOCK
213 * @see #WHEN_EXHAUSTED_GROW
214 * @see #setWhenExhaustedAction
215 */
216 public static final byte WHEN_EXHAUSTED_FAIL = 0;
217
218 /**
219 * A "when exhausted action" type indicating that when the pool
220 * is exhausted (i.e., the maximum number
221 * of active objects has been reached), the {@link #borrowObject}
222 * method should block until a new object is available, or the
223 * {@link #getMaxWait maximum wait time} has been reached.
224 * @see #WHEN_EXHAUSTED_FAIL
225 * @see #WHEN_EXHAUSTED_GROW
226 * @see #setMaxWait
227 * @see #getMaxWait
228 * @see #setWhenExhaustedAction
229 */
230 public static final byte WHEN_EXHAUSTED_BLOCK = 1;
231
232 /**
233 * A "when exhausted action" type indicating that when the pool is
234 * exhausted (i.e., the maximum number
235 * of active objects has been reached), the {@link #borrowObject}
236 * method should simply create a new object anyway.
237 * @see #WHEN_EXHAUSTED_FAIL
238 * @see #WHEN_EXHAUSTED_GROW
239 * @see #setWhenExhaustedAction
240 */
241 public static final byte WHEN_EXHAUSTED_GROW = 2;
242
243 /**
244 * The default cap on the number of idle instances (per key) in the pool.
245 * @see #getMaxIdle
246 * @see #setMaxIdle
247 */
248 public static final int DEFAULT_MAX_IDLE = 8;
249
250 /**
251 * The default cap on the total number of active instances (per key)
252 * from the pool.
253 * @see #getMaxActive
254 * @see #setMaxActive
255 */
256 public static final int DEFAULT_MAX_ACTIVE = 8;
257
258 /**
259 * The default cap on the the overall maximum number of objects that can
260 * exist at one time.
261 * @see #getMaxTotal
262 * @see #setMaxTotal
263 */
264 public static final int DEFAULT_MAX_TOTAL = -1;
265
266 /**
267 * The default "when exhausted action" for the pool.
268 * @see #WHEN_EXHAUSTED_BLOCK
269 * @see #WHEN_EXHAUSTED_FAIL
270 * @see #WHEN_EXHAUSTED_GROW
271 * @see #setWhenExhaustedAction
272 */
273 public static final byte DEFAULT_WHEN_EXHAUSTED_ACTION = WHEN_EXHAUSTED_BLOCK;
274
275 /**
276 * The default maximum amount of time (in milliseconds) the
277 * {@link #borrowObject} method should block before throwing
278 * an exception when the pool is exhausted and the
279 * {@link #getWhenExhaustedAction "when exhausted" action} is
280 * {@link #WHEN_EXHAUSTED_BLOCK}.
281 * @see #getMaxWait
282 * @see #setMaxWait
283 */
284 public static final long DEFAULT_MAX_WAIT = -1L;
285
286 /**
287 * The default "test on borrow" value.
288 * @see #getTestOnBorrow
289 * @see #setTestOnBorrow
290 */
291 public static final boolean DEFAULT_TEST_ON_BORROW = false;
292
293 /**
294 * The default "test on return" value.
295 * @see #getTestOnReturn
296 * @see #setTestOnReturn
297 */
298 public static final boolean DEFAULT_TEST_ON_RETURN = false;
299
300 /**
301 * The default "test while idle" value.
302 * @see #getTestWhileIdle
303 * @see #setTestWhileIdle
304 * @see #getTimeBetweenEvictionRunsMillis
305 * @see #setTimeBetweenEvictionRunsMillis
306 */
307 public static final boolean DEFAULT_TEST_WHILE_IDLE = false;
308
309 /**
310 * The default "time between eviction runs" value.
311 * @see #getTimeBetweenEvictionRunsMillis
312 * @see #setTimeBetweenEvictionRunsMillis
313 */
314 public static final long DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS = -1L;
315
316 /**
317 * The default number of objects to examine per run in the
318 * idle object evictor.
319 * @see #getNumTestsPerEvictionRun
320 * @see #setNumTestsPerEvictionRun
321 * @see #getTimeBetweenEvictionRunsMillis
322 * @see #setTimeBetweenEvictionRunsMillis
323 */
324 public static final int DEFAULT_NUM_TESTS_PER_EVICTION_RUN = 3;
325
326 /**
327 * The default value for {@link #getMinEvictableIdleTimeMillis}.
328 * @see #getMinEvictableIdleTimeMillis
329 * @see #setMinEvictableIdleTimeMillis
330 */
331 public static final long DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS = 1000L * 60L * 30L;
332
333 /**
334 * The default minimum level of idle objects in the pool.
335 * @since Pool 1.3
336 * @see #setMinIdle
337 * @see #getMinIdle
338 */
339 public static final int DEFAULT_MIN_IDLE = 0;
340
341 /**
342 * The default LIFO status. True means that borrowObject returns the
343 * most recently used ("last in") idle object in a pool (if there are
344 * idle instances available). False means that pools behave as FIFO
345 * queues - objects are taken from idle object pools in the order that
346 * they are returned.
347 * @see #setLifo
348 */
349 public static final boolean DEFAULT_LIFO = true;
350
351 //--- constructors -----------------------------------------------
352
353 /**
354 * Create a new <code>GenericKeyedObjectPool</code> with no factory.
355 *
356 * @see #GenericKeyedObjectPool(KeyedPoolableObjectFactory)
357 * @see #setFactory(KeyedPoolableObjectFactory)
358 */
359 public GenericKeyedObjectPool() {
360 this(null, DEFAULT_MAX_ACTIVE, DEFAULT_WHEN_EXHAUSTED_ACTION, DEFAULT_MAX_WAIT, DEFAULT_MAX_IDLE,
361 DEFAULT_TEST_ON_BORROW, DEFAULT_TEST_ON_RETURN, DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS,
362 DEFAULT_NUM_TESTS_PER_EVICTION_RUN, DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS, DEFAULT_TEST_WHILE_IDLE);
363 }
364
365 /**
366 * Create a new <code>GenericKeyedObjectPool</code> using the specified values.
367 * @param factory the <code>KeyedPoolableObjectFactory</code> to use to create, validate, and destroy
368 * objects if not <code>null</code>
369 */
370 public GenericKeyedObjectPool(KeyedPoolableObjectFactory factory) {
371 this(factory, DEFAULT_MAX_ACTIVE, DEFAULT_WHEN_EXHAUSTED_ACTION, DEFAULT_MAX_WAIT, DEFAULT_MAX_IDLE,
372 DEFAULT_TEST_ON_BORROW, DEFAULT_TEST_ON_RETURN, DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS,
373 DEFAULT_NUM_TESTS_PER_EVICTION_RUN, DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS, DEFAULT_TEST_WHILE_IDLE);
374 }
375
376 /**
377 * Create a new <code>GenericKeyedObjectPool</code> using the specified values.
378 * @param factory the <code>KeyedPoolableObjectFactory</code> to use to create, validate, and destroy objects
379 * if not <code>null</code>
380 * @param config a non-<code>null</code> {@link GenericKeyedObjectPool.Config} describing the configuration
381 */
382 public GenericKeyedObjectPool(KeyedPoolableObjectFactory factory, GenericKeyedObjectPool.Config config) {
383 this(factory, config.maxActive, config.whenExhaustedAction, config.maxWait, config.maxIdle, config.maxTotal,
384 config.minIdle, config.testOnBorrow, config.testOnReturn, config.timeBetweenEvictionRunsMillis,
385 config.numTestsPerEvictionRun, config.minEvictableIdleTimeMillis, config.testWhileIdle, config.lifo);
386 }
387
388 /**
389 * Create a new <code>GenericKeyedObjectPool</code> using the specified values.
390 * @param factory the <code>KeyedPoolableObjectFactory</code> to use to create, validate, and destroy objects
391 * if not <code>null</code>
392 * @param maxActive the maximum number of objects that can be borrowed from me at one time (see {@link #setMaxActive})
393 */
394 public GenericKeyedObjectPool(KeyedPoolableObjectFactory factory, int maxActive) {
395 this(factory,maxActive, DEFAULT_WHEN_EXHAUSTED_ACTION, DEFAULT_MAX_WAIT, DEFAULT_MAX_IDLE,
396 DEFAULT_TEST_ON_BORROW, DEFAULT_TEST_ON_RETURN, DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS,
397 DEFAULT_NUM_TESTS_PER_EVICTION_RUN, DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS, DEFAULT_TEST_WHILE_IDLE);
398 }
399
400 /**
401 * Create a new <code>GenericKeyedObjectPool</code> using the specified values.
402 * @param factory the <code>KeyedPoolableObjectFactory</code> to use to create, validate, and destroy objects
403 * if not <code>null</code>
404 * @param maxActive the maximum number of objects that can be borrowed from me at one time (see {@link #setMaxActive})
405 * @param whenExhaustedAction the action to take when the pool is exhausted (see {@link #setWhenExhaustedAction})
406 * @param maxWait the maximum amount of time to wait for an idle object when the pool is exhausted and
407 * <code>whenExhaustedAction</code> is {@link #WHEN_EXHAUSTED_BLOCK} (otherwise ignored) (see {@link #setMaxWait})
408 */
409 public GenericKeyedObjectPool(KeyedPoolableObjectFactory factory, int maxActive, byte whenExhaustedAction,
410 long maxWait) {
411 this(factory, maxActive, whenExhaustedAction, maxWait, DEFAULT_MAX_IDLE, DEFAULT_TEST_ON_BORROW,
412 DEFAULT_TEST_ON_RETURN, DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS, DEFAULT_NUM_TESTS_PER_EVICTION_RUN,
413 DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS, DEFAULT_TEST_WHILE_IDLE);
414 }
415
416 /**
417 * Create a new <code>GenericKeyedObjectPool</code> using the specified values.
418 * @param factory the <code>KeyedPoolableObjectFactory</code> to use to create, validate, and destroy objects
419 * if not <code>null</code>
420 * @param maxActive the maximum number of objects that can be borrowed from me at one time (see {@link #setMaxActive})
421 * @param maxWait the maximum amount of time to wait for an idle object when the pool is exhausted and
422 * <code>whenExhaustedAction</code> is {@link #WHEN_EXHAUSTED_BLOCK} (otherwise ignored) (see {@link #setMaxWait})
423 * @param whenExhaustedAction the action to take when the pool is exhausted (see {@link #setWhenExhaustedAction})
424 * @param testOnBorrow whether or not to validate objects before they are returned by the {@link #borrowObject}
425 * method (see {@link #setTestOnBorrow})
426 * @param testOnReturn whether or not to validate objects after they are returned to the {@link #returnObject}
427 * method (see {@link #setTestOnReturn})
428 */
429 public GenericKeyedObjectPool(KeyedPoolableObjectFactory factory, int maxActive, byte whenExhaustedAction,
430 long maxWait, boolean testOnBorrow, boolean testOnReturn) {
431 this(factory, maxActive, whenExhaustedAction, maxWait, DEFAULT_MAX_IDLE,testOnBorrow,testOnReturn,
432 DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS, DEFAULT_NUM_TESTS_PER_EVICTION_RUN,
433 DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS, DEFAULT_TEST_WHILE_IDLE);
434 }
435
436 /**
437 * Create a new <code>GenericKeyedObjectPool</code> using the specified values.
438 * @param factory the <code>KeyedPoolableObjectFactory</code> to use to create, validate, and destroy objects
439 * if not <code>null</code>
440 * @param maxActive the maximum number of objects that can be borrowed from me at one time
441 * (see {@link #setMaxActive})
442 * @param whenExhaustedAction the action to take when the pool is exhausted (see {@link #setWhenExhaustedAction})
443 * @param maxWait the maximum amount of time to wait for an idle object when the pool is exhausted and
444 * <code>whenExhaustedAction</code> is {@link #WHEN_EXHAUSTED_BLOCK} (otherwise ignored) (see {@link #setMaxWait})
445 * @param maxIdle the maximum number of idle objects in my pool (see {@link #setMaxIdle})
446 */
447 public GenericKeyedObjectPool(KeyedPoolableObjectFactory factory, int maxActive, byte whenExhaustedAction,
448 long maxWait, int maxIdle) {
449 this(factory, maxActive, whenExhaustedAction, maxWait, maxIdle, DEFAULT_TEST_ON_BORROW, DEFAULT_TEST_ON_RETURN,
450 DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS, DEFAULT_NUM_TESTS_PER_EVICTION_RUN,
451 DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS, DEFAULT_TEST_WHILE_IDLE);
452 }
453
454 /**
455 * Create a new <code>GenericKeyedObjectPool</code> using the specified values.
456 * @param factory the <code>KeyedPoolableObjectFactory</code> to use to create, validate, and destroy objects
457 * if not <code>null</code>
458 * @param maxActive the maximum number of objects that can be borrowed from me at one time
459 * (see {@link #setMaxActive})
460 * @param whenExhaustedAction the action to take when the pool is exhausted (see {@link #setWhenExhaustedAction})
461 * @param maxWait the maximum amount of time to wait for an idle object when the pool is exhausted and
462 * <code>whenExhaustedAction</code> is {@link #WHEN_EXHAUSTED_BLOCK} (otherwise ignored) (see {@link #getMaxWait})
463 * @param maxIdle the maximum number of idle objects in my pool (see {@link #setMaxIdle})
464 * @param testOnBorrow whether or not to validate objects before they are returned by the {@link #borrowObject}
465 * method (see {@link #setTestOnBorrow})
466 * @param testOnReturn whether or not to validate objects after they are returned to the {@link #returnObject}
467 * method (see {@link #setTestOnReturn})
468 */
469 public GenericKeyedObjectPool(KeyedPoolableObjectFactory factory, int maxActive, byte whenExhaustedAction,
470 long maxWait, int maxIdle, boolean testOnBorrow, boolean testOnReturn) {
471 this(factory, maxActive, whenExhaustedAction, maxWait, maxIdle, testOnBorrow, testOnReturn,
472 DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS, DEFAULT_NUM_TESTS_PER_EVICTION_RUN,
473 DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS, DEFAULT_TEST_WHILE_IDLE);
474 }
475
476 /**
477 * Create a new <code>GenericKeyedObjectPool</code> using the specified values.
478 * @param factory the <code>KeyedPoolableObjectFactory</code> to use to create, validate, and destroy objects
479 * if not <code>null</code>
480 * @param maxActive the maximum number of objects that can be borrowed from me at one time
481 * (see {@link #setMaxActive})
482 * @param whenExhaustedAction the action to take when the pool is exhausted
483 * (see {@link #setWhenExhaustedAction})
484 * @param maxWait the maximum amount of time to wait for an idle object when the pool is exhausted and
485 * <code>whenExhaustedAction</code> is {@link #WHEN_EXHAUSTED_BLOCK} (otherwise ignored) (see {@link #setMaxWait})
486 * @param maxIdle the maximum number of idle objects in my pool (see {@link #setMaxIdle})
487 * @param testOnBorrow whether or not to validate objects before they are returned by the {@link #borrowObject}
488 * method (see {@link #setTestOnBorrow})
489 * @param testOnReturn whether or not to validate objects after they are returned to the {@link #returnObject}
490 * method (see {@link #setTestOnReturn})
491 * @param timeBetweenEvictionRunsMillis the amount of time (in milliseconds) to sleep between examining idle
492 * objects for eviction (see {@link #setTimeBetweenEvictionRunsMillis})
493 * @param numTestsPerEvictionRun the number of idle objects to examine per run within the idle object eviction
494 * thread (if any) (see {@link #setNumTestsPerEvictionRun})
495 * @param minEvictableIdleTimeMillis the minimum number of milliseconds an object can sit idle in the pool before
496 * it is eligible for eviction (see {@link #setMinEvictableIdleTimeMillis})
497 * @param testWhileIdle whether or not to validate objects in the idle object eviction thread, if any
498 * (see {@link #setTestWhileIdle})
499 */
500 public GenericKeyedObjectPool(KeyedPoolableObjectFactory factory, int maxActive, byte whenExhaustedAction,
501 long maxWait, int maxIdle, boolean testOnBorrow, boolean testOnReturn, long timeBetweenEvictionRunsMillis,
502 int numTestsPerEvictionRun, long minEvictableIdleTimeMillis, boolean testWhileIdle) {
503 this(factory, maxActive, whenExhaustedAction, maxWait, maxIdle, GenericKeyedObjectPool.DEFAULT_MAX_TOTAL,
504 testOnBorrow, testOnReturn, timeBetweenEvictionRunsMillis, numTestsPerEvictionRun,
505 minEvictableIdleTimeMillis, testWhileIdle);
506 }
507
508 /**
509 * Create a new <code>GenericKeyedObjectPool</code> using the specified values.
510 * @param factory the <code>KeyedPoolableObjectFactory</code> to use to create, validate, and destroy objects
511 * if not <code>null</code>
512 * @param maxActive the maximum number of objects that can be borrowed from me at one time
513 * (see {@link #setMaxActive})
514 * @param whenExhaustedAction the action to take when the pool is exhausted (see {@link #setWhenExhaustedAction})
515 * @param maxWait the maximum amount of time to wait for an idle object when the pool is exhausted and
516 * <code>whenExhaustedAction</code> is {@link #WHEN_EXHAUSTED_BLOCK} (otherwise ignored) (see {@link #setMaxWait})
517 * @param maxIdle the maximum number of idle objects in my pool (see {@link #setMaxIdle})
518 * @param maxTotal the maximum number of objects that can exists at one time (see {@link #setMaxTotal})
519 * @param testOnBorrow whether or not to validate objects before they are returned by the {@link #borrowObject}
520 * method (see {@link #setTestOnBorrow})
521 * @param testOnReturn whether or not to validate objects after they are returned to the {@link #returnObject}
522 * method (see {@link #setTestOnReturn})
523 * @param timeBetweenEvictionRunsMillis the amount of time (in milliseconds) to sleep between examining idle
524 * objects for eviction (see {@link #setTimeBetweenEvictionRunsMillis})
525 * @param numTestsPerEvictionRun the number of idle objects to examine per run within the idle object eviction
526 * thread (if any) (see {@link #setNumTestsPerEvictionRun})
527 * @param minEvictableIdleTimeMillis the minimum number of milliseconds an object can sit idle in the pool
528 * before it is eligible for eviction (see {@link #setMinEvictableIdleTimeMillis})
529 * @param testWhileIdle whether or not to validate objects in the idle object eviction thread, if any
530 * (see {@link #setTestWhileIdle})
531 */
532 public GenericKeyedObjectPool(KeyedPoolableObjectFactory factory, int maxActive, byte whenExhaustedAction,
533 long maxWait, int maxIdle, int maxTotal, boolean testOnBorrow, boolean testOnReturn,
534 long timeBetweenEvictionRunsMillis, int numTestsPerEvictionRun, long minEvictableIdleTimeMillis,
535 boolean testWhileIdle) {
536 this(factory, maxActive, whenExhaustedAction, maxWait, maxIdle, maxTotal,
537 GenericKeyedObjectPool.DEFAULT_MIN_IDLE, testOnBorrow, testOnReturn, timeBetweenEvictionRunsMillis,
538 numTestsPerEvictionRun, minEvictableIdleTimeMillis, testWhileIdle);
539 }
540
541 /**
542 * Create a new <code>GenericKeyedObjectPool</code> using the specified values.
543 * @param factory the <code>KeyedPoolableObjectFactory</code> to use to create, validate, and destroy objects
544 * if not <code>null</code>
545 * @param maxActive the maximum number of objects that can be borrowed at one time (see {@link #setMaxActive})
546 * @param whenExhaustedAction the action to take when the pool is exhausted (see {@link #setWhenExhaustedAction})
547 * @param maxWait the maximum amount of time to wait for an idle object when the pool is exhausted and
548 * <code>whenExhaustedAction</code> is {@link #WHEN_EXHAUSTED_BLOCK} (otherwise ignored) (see {@link #setMaxWait})
549 * @param maxIdle the maximum number of idle objects in my pool (see {@link #setMaxIdle})
550 * @param maxTotal the maximum number of objects that can exists at one time (see {@link #setMaxTotal})
551 * @param minIdle the minimum number of idle objects to have in the pool at any one time (see {@link #setMinIdle})
552 * @param testOnBorrow whether or not to validate objects before they are returned by the {@link #borrowObject}
553 * method (see {@link #setTestOnBorrow})
554 * @param testOnReturn whether or not to validate objects after they are returned to the {@link #returnObject}
555 * method (see {@link #setTestOnReturn})
556 * @param timeBetweenEvictionRunsMillis the amount of time (in milliseconds) to sleep between examining idle
557 * objects
558 * for eviction (see {@link #setTimeBetweenEvictionRunsMillis})
559 * @param numTestsPerEvictionRun the number of idle objects to examine per run within the idle object eviction
560 * thread (if any) (see {@link #setNumTestsPerEvictionRun})
561 * @param minEvictableIdleTimeMillis the minimum number of milliseconds an object can sit idle in the pool before
562 * it is eligible for eviction (see {@link #setMinEvictableIdleTimeMillis})
563 * @param testWhileIdle whether or not to validate objects in the idle object eviction thread, if any
564 * (see {@link #setTestWhileIdle})
565 * @since Pool 1.3
566 */
567 public GenericKeyedObjectPool(KeyedPoolableObjectFactory factory, int maxActive, byte whenExhaustedAction,
568 long maxWait, int maxIdle, int maxTotal, int minIdle, boolean testOnBorrow, boolean testOnReturn,
569 long timeBetweenEvictionRunsMillis, int numTestsPerEvictionRun, long minEvictableIdleTimeMillis,
570 boolean testWhileIdle) {
571 this(factory, maxActive, whenExhaustedAction, maxWait, maxIdle, maxTotal, minIdle, testOnBorrow, testOnReturn,
572 timeBetweenEvictionRunsMillis, numTestsPerEvictionRun, minEvictableIdleTimeMillis, testWhileIdle,
573 DEFAULT_LIFO);
574 }
575
576 /**
577 * Create a new <code>GenericKeyedObjectPool</code> using the specified values.
578 * @param factory the <code>KeyedPoolableObjectFactory</code> to use to create, validate, and destroy objects
579 * if not <code>null</code>
580 * @param maxActive the maximum number of objects that can be borrowed at one time
581 * (see {@link #setMaxActive})
582 * @param whenExhaustedAction the action to take when the pool is exhausted (see {@link #setWhenExhaustedAction})
583 * @param maxWait the maximum amount of time to wait for an idle object when the pool is exhausted and
584 * <code>whenExhaustedAction</code> is {@link #WHEN_EXHAUSTED_BLOCK} (otherwise ignored) (see {@link #setMaxWait})
585 * @param maxIdle the maximum number of idle objects in my pool (see {@link #setMaxIdle})
586 * @param maxTotal the maximum number of objects that can exists at one time (see {@link #setMaxTotal})
587 * @param minIdle the minimum number of idle objects to have in the pool at any one time (see {@link #setMinIdle})
588 * @param testOnBorrow whether or not to validate objects before they are returned by the {@link #borrowObject}
589 * method (see {@link #setTestOnBorrow})
590 * @param testOnReturn whether or not to validate objects after they are returned to the {@link #returnObject}
591 * method (see {@link #setTestOnReturn})
592 * @param timeBetweenEvictionRunsMillis the amount of time (in milliseconds) to sleep between examining idle
593 * objects for eviction (see {@link #setTimeBetweenEvictionRunsMillis})
594 * @param numTestsPerEvictionRun the number of idle objects to examine per run within the idle object eviction
595 * thread (if any) (see {@link #setNumTestsPerEvictionRun})
596 * @param minEvictableIdleTimeMillis the minimum number of milliseconds an object can sit idle in the pool before
597 * it is eligible for eviction (see {@link #setMinEvictableIdleTimeMillis})
598 * @param testWhileIdle whether or not to validate objects in the idle object eviction thread, if any
599 * (see {@link #setTestWhileIdle})
600 * @param lifo whether or not the pools behave as LIFO (last in first out) queues (see {@link #setLifo})
601 * @since Pool 1.4
602 */
603 public GenericKeyedObjectPool(KeyedPoolableObjectFactory factory, int maxActive, byte whenExhaustedAction,
604 long maxWait, int maxIdle, int maxTotal, int minIdle, boolean testOnBorrow, boolean testOnReturn,
605 long timeBetweenEvictionRunsMillis, int numTestsPerEvictionRun, long minEvictableIdleTimeMillis,
606 boolean testWhileIdle, boolean lifo) {
607 _factory = factory;
608 _maxActive = maxActive;
609 _lifo = lifo;
610 switch (whenExhaustedAction) {
611 case WHEN_EXHAUSTED_BLOCK:
612 case WHEN_EXHAUSTED_FAIL:
613 case WHEN_EXHAUSTED_GROW:
614 _whenExhaustedAction = whenExhaustedAction;
615 break;
616 default:
617 throw new IllegalArgumentException("whenExhaustedAction " + whenExhaustedAction + " not recognized.");
618 }
619 _maxWait = maxWait;
620 _maxIdle = maxIdle;
621 _maxTotal = maxTotal;
622 _minIdle = minIdle;
623 _testOnBorrow = testOnBorrow;
624 _testOnReturn = testOnReturn;
625 _timeBetweenEvictionRunsMillis = timeBetweenEvictionRunsMillis;
626 _numTestsPerEvictionRun = numTestsPerEvictionRun;
627 _minEvictableIdleTimeMillis = minEvictableIdleTimeMillis;
628 _testWhileIdle = testWhileIdle;
629
630 _poolMap = new HashMap();
631 _poolList = new CursorableLinkedList();
632
633 startEvictor(_timeBetweenEvictionRunsMillis);
634 }
635
636 //--- public methods ---------------------------------------------
637
638 //--- configuration methods --------------------------------------
639
640 /**
641 * Returns the cap on the number of object instances allocated by the pool
642 * (checked out or idle), per key.
643 * A negative value indicates no limit.
644 *
645 * @return the cap on the number of active instances per key.
646 * @see #setMaxActive
647 */
648 public synchronized int getMaxActive() {
649 return _maxActive;
650 }
651
652 /**
653 * Sets the cap on the number of object instances managed by the pool per key.
654 * @param maxActive The cap on the number of object instances per key.
655 * Use a negative value for no limit.
656 *
657 * @see #getMaxActive
658 */
659 public synchronized void setMaxActive(int maxActive) {
660 _maxActive = maxActive;
661 allocate();
662 }
663
664 /**
665 * Returns the overall maximum number of objects (across pools) that can
666 * exist at one time. A negative value indicates no limit.
667 * @return the maximum number of instances in circulation at one time.
668 * @see #setMaxTotal
669 */
670 public synchronized int getMaxTotal() {
671 return _maxTotal;
672 }
673
674 /**
675 * Sets the cap on the total number of instances from all pools combined.
676 * When <code>maxTotal</code> is set to a
677 * positive value and {@link #borrowObject borrowObject} is invoked
678 * when at the limit with no idle instances available, an attempt is made to
679 * create room by clearing the oldest 15% of the elements from the keyed
680 * pools.
681 *
682 * @param maxTotal The cap on the total number of instances across pools.
683 * Use a negative value for no limit.
684 * @see #getMaxTotal
685 */
686 public synchronized void setMaxTotal(int maxTotal) {
687 _maxTotal = maxTotal;
688 allocate();
689 }
690
691 /**
692 * Returns the action to take when the {@link #borrowObject} method
693 * is invoked when the pool is exhausted (the maximum number
694 * of "active" objects has been reached).
695 *
696 * @return one of {@link #WHEN_EXHAUSTED_BLOCK},
697 * {@link #WHEN_EXHAUSTED_FAIL} or {@link #WHEN_EXHAUSTED_GROW}
698 * @see #setWhenExhaustedAction
699 */
700 public synchronized byte getWhenExhaustedAction() {
701 return _whenExhaustedAction;
702 }
703
704 /**
705 * Sets the action to take when the {@link #borrowObject} method
706 * is invoked when the pool is exhausted (the maximum number
707 * of "active" objects has been reached).
708 *
709 * @param whenExhaustedAction the action code, which must be one of
710 * {@link #WHEN_EXHAUSTED_BLOCK}, {@link #WHEN_EXHAUSTED_FAIL},
711 * or {@link #WHEN_EXHAUSTED_GROW}
712 * @see #getWhenExhaustedAction
713 */
714 public synchronized void setWhenExhaustedAction(byte whenExhaustedAction) {
715 switch(whenExhaustedAction) {
716 case WHEN_EXHAUSTED_BLOCK:
717 case WHEN_EXHAUSTED_FAIL:
718 case WHEN_EXHAUSTED_GROW:
719 _whenExhaustedAction = whenExhaustedAction;
720 allocate();
721 break;
722 default:
723 throw new IllegalArgumentException("whenExhaustedAction " + whenExhaustedAction + " not recognized.");
724 }
725 }
726
727
728 /**
729 * Returns the maximum amount of time (in milliseconds) the
730 * {@link #borrowObject} method should block before throwing
731 * an exception when the pool is exhausted and the
732 * {@link #setWhenExhaustedAction "when exhausted" action} is
733 * {@link #WHEN_EXHAUSTED_BLOCK}.
734 *
735 * When less than or equal to 0, the {@link #borrowObject} method
736 * may block indefinitely.
737 *
738 * @return the maximum number of milliseconds borrowObject will block.
739 * @see #setMaxWait
740 * @see #setWhenExhaustedAction
741 * @see #WHEN_EXHAUSTED_BLOCK
742 */
743 public synchronized long getMaxWait() {
744 return _maxWait;
745 }
746
747 /**
748 * Sets the maximum amount of time (in milliseconds) the
749 * {@link #borrowObject} method should block before throwing
750 * an exception when the pool is exhausted and the
751 * {@link #setWhenExhaustedAction "when exhausted" action} is
752 * {@link #WHEN_EXHAUSTED_BLOCK}.
753 *
754 * When less than or equal to 0, the {@link #borrowObject} method
755 * may block indefinitely.
756 *
757 * @param maxWait the maximum number of milliseconds borrowObject will block or negative for indefinitely.
758 * @see #getMaxWait
759 * @see #setWhenExhaustedAction
760 * @see #WHEN_EXHAUSTED_BLOCK
761 */
762 public synchronized void setMaxWait(long maxWait) {
763 _maxWait = maxWait;
764 }
765
766 /**
767 * Returns the cap on the number of "idle" instances per key.
768 * @return the maximum number of "idle" instances that can be held
769 * in a given keyed pool.
770 * @see #setMaxIdle
771 */
772 public synchronized int getMaxIdle() {
773 return _maxIdle;
774 }
775
776 /**
777 * Sets the cap on the number of "idle" instances in the pool.
778 * If maxIdle is set too low on heavily loaded systems it is possible you
779 * will see objects being destroyed and almost immediately new objects
780 * being created. This is a result of the active threads momentarily
781 * returning objects faster than they are requesting them them, causing the
782 * number of idle objects to rise above maxIdle. The best value for maxIdle
783 * for heavily loaded system will vary but the default is a good starting
784 * point.
785 * @param maxIdle the maximum number of "idle" instances that can be held
786 * in a given keyed pool. Use a negative value for no limit.
787 * @see #getMaxIdle
788 * @see #DEFAULT_MAX_IDLE
789 */
790 public synchronized void setMaxIdle(int maxIdle) {
791 _maxIdle = maxIdle;
792 allocate();
793 }
794
795 /**
796 * Sets the minimum number of idle objects to maintain in each of the keyed
797 * pools. This setting has no effect unless
798 * <code>timeBetweenEvictionRunsMillis > 0</code> and attempts to ensure
799 * that each pool has the required minimum number of instances are only
800 * made during idle object eviction runs.
801 * @param poolSize - The minimum size of the each keyed pool
802 * @since Pool 1.3
803 * @see #getMinIdle
804 * @see #setTimeBetweenEvictionRunsMillis
805 */
806 public synchronized void setMinIdle(int poolSize) {
807 _minIdle = poolSize;
808 }
809
810 /**
811 * Returns the minimum number of idle objects to maintain in each of the keyed
812 * pools. This setting has no effect unless
813 * <code>timeBetweenEvictionRunsMillis > 0</code> and attempts to ensure
814 * that each pool has the required minimum number of instances are only
815 * made during idle object eviction runs.
816 * @return minimum size of the each keyed pool
817 * @since Pool 1.3
818 * @see #setTimeBetweenEvictionRunsMillis
819 */
820 public synchronized int getMinIdle() {
821 return _minIdle;
822 }
823
824 /**
825 * When <code>true</code>, objects will be
826 * {@link org.apache.commons.pool.PoolableObjectFactory#validateObject validated}
827 * before being returned by the {@link #borrowObject}
828 * method. If the object fails to validate,
829 * it will be dropped from the pool, and we will attempt
830 * to borrow another.
831 *
832 * @return <code>true</code> if objects are validated before being borrowed.
833 * @see #setTestOnBorrow
834 */
835 public boolean getTestOnBorrow() {
836 return _testOnBorrow;
837 }
838
839 /**
840 * When <code>true</code>, objects will be
841 * {@link org.apache.commons.pool.PoolableObjectFactory#validateObject validated}
842 * before being returned by the {@link #borrowObject}
843 * method. If the object fails to validate,
844 * it will be dropped from the pool, and we will attempt
845 * to borrow another.
846 *
847 * @param testOnBorrow whether object should be validated before being returned by borrowObject.
848 * @see #getTestOnBorrow
849 */
850 public void setTestOnBorrow(boolean testOnBorrow) {
851 _testOnBorrow = testOnBorrow;
852 }
853
854 /**
855 * When <code>true</code>, objects will be
856 * {@link org.apache.commons.pool.PoolableObjectFactory#validateObject validated}
857 * before being returned to the pool within the
858 * {@link #returnObject}.
859 *
860 * @return <code>true</code> when objects will be validated before being returned.
861 * @see #setTestOnReturn
862 */
863 public boolean getTestOnReturn() {
864 return _testOnReturn;
865 }
866
867 /**
868 * When <code>true</code>, objects will be
869 * {@link org.apache.commons.pool.PoolableObjectFactory#validateObject validated}
870 * before being returned to the pool within the
871 * {@link #returnObject}.
872 *
873 * @param testOnReturn <code>true</code> so objects will be validated before being returned.
874 * @see #getTestOnReturn
875 */
876 public void setTestOnReturn(boolean testOnReturn) {
877 _testOnReturn = testOnReturn;
878 }
879
880 /**
881 * Returns the number of milliseconds to sleep between runs of the
882 * idle object evictor thread.
883 * When non-positive, no idle object evictor thread will be
884 * run.
885 *
886 * @return milliseconds to sleep between evictor runs.
887 * @see #setTimeBetweenEvictionRunsMillis
888 */
889 public synchronized long getTimeBetweenEvictionRunsMillis() {
890 return _timeBetweenEvictionRunsMillis;
891 }
892
893 /**
894 * Sets the number of milliseconds to sleep between runs of the
895 * idle object evictor thread.
896 * When non-positive, no idle object evictor thread will be
897 * run.
898 *
899 * @param timeBetweenEvictionRunsMillis milliseconds to sleep between evictor runs.
900 * @see #getTimeBetweenEvictionRunsMillis
901 */
902 public synchronized void setTimeBetweenEvictionRunsMillis(long timeBetweenEvictionRunsMillis) {
903 _timeBetweenEvictionRunsMillis = timeBetweenEvictionRunsMillis;
904 startEvictor(_timeBetweenEvictionRunsMillis);
905 }
906
907 /**
908 * Returns the number of objects to examine during each run of the
909 * idle object evictor thread (if any).
910 *
911 * @return number of objects to examine each eviction run.
912 * @see #setNumTestsPerEvictionRun
913 * @see #setTimeBetweenEvictionRunsMillis
914 */
915 public synchronized int getNumTestsPerEvictionRun() {
916 return _numTestsPerEvictionRun;
917 }
918
919 /**
920 * Sets the number of objects to examine during each run of the
921 * idle object evictor thread (if any).
922 * <p>
923 * When a negative value is supplied,
924 * <code>ceil({@link #getNumIdle()})/abs({@link #getNumTestsPerEvictionRun})</code>
925 * tests will be run. I.e., when the value is <code>-n</code>, roughly one <code>n</code>th of the
926 * idle objects will be tested per run.
927 *
928 * @param numTestsPerEvictionRun number of objects to examine each eviction run.
929 * @see #getNumTestsPerEvictionRun
930 * @see #setTimeBetweenEvictionRunsMillis
931 */
932 public synchronized void setNumTestsPerEvictionRun(int numTestsPerEvictionRun) {
933 _numTestsPerEvictionRun = numTestsPerEvictionRun;
934 }
935
936 /**
937 * Returns the minimum amount of time an object may sit idle in the pool
938 * before it is eligible for eviction by the idle object evictor
939 * (if any).
940 *
941 * @return minimum amount of time an object may sit idle in the pool before it is eligible for eviction.
942 * @see #setMinEvictableIdleTimeMillis
943 * @see #setTimeBetweenEvictionRunsMillis
944 */
945 public synchronized long getMinEvictableIdleTimeMillis() {
946 return _minEvictableIdleTimeMillis;
947 }
948
949 /**
950 * Sets the minimum amount of time an object may sit idle in the pool
951 * before it is eligible for eviction by the idle object evictor
952 * (if any).
953 * When non-positive, no objects will be evicted from the pool
954 * due to idle time alone.
955 *
956 * @param minEvictableIdleTimeMillis minimum amount of time an object may sit idle in the pool before
957 * it is eligible for eviction.
958 * @see #getMinEvictableIdleTimeMillis
959 * @see #setTimeBetweenEvictionRunsMillis
960 */
961 public synchronized void setMinEvictableIdleTimeMillis(long minEvictableIdleTimeMillis) {
962 _minEvictableIdleTimeMillis = minEvictableIdleTimeMillis;
963 }
964
965 /**
966 * When <code>true</code>, objects will be
967 * {@link org.apache.commons.pool.PoolableObjectFactory#validateObject validated}
968 * by the idle object evictor (if any). If an object
969 * fails to validate, it will be dropped from the pool.
970 *
971 * @return <code>true</code> when objects are validated when borrowed.
972 * @see #setTestWhileIdle
973 * @see #setTimeBetweenEvictionRunsMillis
974 */
975 public synchronized boolean getTestWhileIdle() {
976 return _testWhileIdle;
977 }
978
979 /**
980 * When <code>true</code>, objects will be
981 * {@link org.apache.commons.pool.PoolableObjectFactory#validateObject validated}
982 * by the idle object evictor (if any). If an object
983 * fails to validate, it will be dropped from the pool.
984 *
985 * @param testWhileIdle <code>true</code> so objects are validated when borrowed.
986 * @see #getTestWhileIdle
987 * @see #setTimeBetweenEvictionRunsMillis
988 */
989 public synchronized void setTestWhileIdle(boolean testWhileIdle) {
990 _testWhileIdle = testWhileIdle;
991 }
992
993 /**
994 * Sets the configuration.
995 * @param conf the new configuration to use.
996 * @see GenericKeyedObjectPool.Config
997 */
998 public synchronized void setConfig(GenericKeyedObjectPool.Config conf) {
999 setMaxIdle(conf.maxIdle);
1000 setMaxActive(conf.maxActive);
1001 setMaxTotal(conf.maxTotal);
1002 setMinIdle(conf.minIdle);
1003 setMaxWait(conf.maxWait);
1004 setWhenExhaustedAction(conf.whenExhaustedAction);
1005 setTestOnBorrow(conf.testOnBorrow);
1006 setTestOnReturn(conf.testOnReturn);
1007 setTestWhileIdle(conf.testWhileIdle);
1008 setNumTestsPerEvictionRun(conf.numTestsPerEvictionRun);
1009 setMinEvictableIdleTimeMillis(conf.minEvictableIdleTimeMillis);
1010 setTimeBetweenEvictionRunsMillis(conf.timeBetweenEvictionRunsMillis);
1011 }
1012
1013 /**
1014 * Whether or not the idle object pools act as LIFO queues. True means
1015 * that borrowObject returns the most recently used ("last in") idle object
1016 * in a pool (if there are idle instances available). False means that
1017 * the pools behave as FIFO queues - objects are taken from idle object
1018 * pools in the order that they are returned.
1019 *
1020 * @return <code>true</code> if the pools are configured to act as LIFO queues
1021 * @since 1.4
1022 */
1023 public synchronized boolean getLifo() {
1024 return _lifo;
1025 }
1026
1027 /**
1028 * Sets the LIFO property of the pools. True means that borrowObject returns
1029 * the most recently used ("last in") idle object in a pool (if there are
1030 * idle instances available). False means that the pools behave as FIFO
1031 * queues - objects are taken from idle object pools in the order that
1032 * they are returned.
1033 *
1034 * @param lifo the new value for the lifo property
1035 * @since 1.4
1036 */
1037 public synchronized void setLifo(boolean lifo) {
1038 this._lifo = lifo;
1039 }
1040
1041 //-- ObjectPool methods ------------------------------------------
1042
1043 /**
1044 * <p>Borrows an object from the keyed pool associated with the given key.</p>
1045 *
1046 * <p>If there is an idle instance available in the pool associated with the given key, then
1047 * either the most-recently returned (if {@link #getLifo() lifo} == true) or "oldest" (lifo == false)
1048 * instance sitting idle in the pool will be activated and returned. If activation fails, or
1049 * {@link #getTestOnBorrow() testOnBorrow} is set to true and validation fails, the instance is destroyed and the
1050 * next available instance is examined. This continues until either a valid instance is returned or there
1051 * are no more idle instances available.</p>
1052 *
1053 * <p>If there are no idle instances available in the pool associated with the given key, behavior
1054 * depends on the {@link #getMaxActive() maxActive}, {@link #getMaxTotal() maxTotal}, and (if applicable)
1055 * {@link #getWhenExhaustedAction() whenExhaustedAction} and {@link #getMaxWait() maxWait} properties. If the
1056 * number of instances checked out from the pool under the given key is less than <code>maxActive</code> and
1057 * the total number of instances in circulation (under all keys) is less than <code>maxTotal</code>, a new instance
1058 * is created, activated and (if applicable) validated and returned to the caller.</p>
1059 *
1060 * <p>If the associated keyed pool is exhausted (no available idle instances and no capacity to create new ones),
1061 * this method will either block ({@link #WHEN_EXHAUSTED_BLOCK}), throw a <code>NoSuchElementException</code>
1062 * ({@link #WHEN_EXHAUSTED_FAIL}), or grow ({@link #WHEN_EXHAUSTED_GROW} - ignoring maxActive, maxTotal properties).
1063 * The length of time that this method will block when <code>whenExhaustedAction == WHEN_EXHAUSTED_BLOCK</code>
1064 * is determined by the {@link #getMaxWait() maxWait} property.</p>
1065 *
1066 * <p>When the pool is exhausted, multiple calling threads may be simultaneously blocked waiting for instances
1067 * to become available. As of pool 1.5, a "fairness" algorithm has been implemented to ensure that threads receive
1068 * available instances in request arrival order.</p>
1069 *
1070 * @param key pool key
1071 * @return object instance from the keyed pool
1072 * @throws NoSuchElementException if a keyed object instance cannot be returned.
1073 */
1074 public Object borrowObject(Object key) throws Exception {
1075 long starttime = System.currentTimeMillis();
1076 Latch latch = new Latch(key);
1077 byte whenExhaustedAction;
1078 long maxWait;
1079 synchronized (this) {
1080 // Get local copy of current config. Can't sync when used later as
1081 // it can result in a deadlock. Has the added advantage that config
1082 // is consistent for entire method execution
1083 whenExhaustedAction = _whenExhaustedAction;
1084 maxWait = _maxWait;
1085
1086 // Add this request to the queue
1087 _allocationQueue.add(latch);
1088
1089 // Work the allocation queue, allocating idle instances and
1090 // instance creation permits in request arrival order
1091 allocate();
1092 }
1093
1094 for(;;) {
1095 synchronized (this) {
1096 assertOpen();
1097 }
1098 // If no object was allocated
1099 if (null == latch.getPair()) {
1100 // Check to see if we were allowed to create one
1101 if (latch.mayCreate()) {
1102 // allow new object to be created
1103 } else {
1104 // the pool is exhausted
1105 switch(whenExhaustedAction) {
1106 case WHEN_EXHAUSTED_GROW:
1107 // allow new object to be created
1108 synchronized (this) {
1109 _allocationQueue.remove(latch);
1110 latch.getPool().incrementInternalProcessingCount();
1111 }
1112 break;
1113 case WHEN_EXHAUSTED_FAIL:
1114 synchronized (this) {
1115 _allocationQueue.remove(latch);
1116 }
1117 throw new NoSuchElementException("Pool exhausted");
1118 case WHEN_EXHAUSTED_BLOCK:
1119 try {
1120 synchronized (latch) {
1121 if (maxWait <= 0) {
1122 latch.wait();
1123 } else {
1124 // this code may be executed again after a notify then continue cycle
1125 // so, need to calculate the amount of time to wait
1126 final long elapsed = (System.currentTimeMillis() - starttime);
1127 final long waitTime = maxWait - elapsed;
1128 if (waitTime > 0)
1129 {
1130 latch.wait(waitTime);
1131 }
1132 }
1133 }
1134 } catch(InterruptedException e) {
1135 Thread.currentThread().interrupt();
1136 throw e;
1137 }
1138 if (maxWait > 0 && ((System.currentTimeMillis() - starttime) >= maxWait)) {
1139 throw new NoSuchElementException("Timeout waiting for idle object");
1140 } else {
1141 continue; // keep looping
1142 }
1143 default:
1144 throw new IllegalArgumentException("whenExhaustedAction " + whenExhaustedAction +
1145 " not recognized.");
1146 }
1147 }
1148 }
1149
1150 boolean newlyCreated = false;
1151 if (null == latch.getPair()) {
1152 try {
1153 Object obj = _factory.makeObject(key);
1154 latch.setPair(new ObjectTimestampPair(obj));
1155 newlyCreated = true;
1156 } finally {
1157 if (!newlyCreated) {
1158 // object cannot be created
1159 synchronized (this) {
1160 latch.getPool().decrementInternalProcessingCount();
1161 // No need to reset latch - about to throw exception
1162 allocate();
1163 }
1164 }
1165 }
1166 }
1167
1168 // activate & validate the object
1169 try {
1170 _factory.activateObject(key, latch.getPair().value);
1171 if (_testOnBorrow && !_factory.validateObject(key, latch.getPair().value)) {
1172 throw new Exception("ValidateObject failed");
1173 }
1174 synchronized (this) {
1175 latch.getPool().decrementInternalProcessingCount();
1176 latch.getPool().incrementActiveCount();
1177 }
1178 return latch.getPair().value;
1179 } catch (Throwable e) {
1180 // object cannot be activated or is invalid
1181 try {
1182 _factory.destroyObject(key, latch.getPair().value);
1183 } catch (Throwable e2) {
1184 // cannot destroy broken object
1185 }
1186 synchronized (this) {
1187 latch.getPool().decrementInternalProcessingCount();
1188 latch.reset();
1189 _allocationQueue.add(0, latch);
1190 allocate();
1191 }
1192 if (newlyCreated) {
1193 throw new NoSuchElementException(
1194 "Could not create a validated object, cause: " +
1195 e.getMessage());
1196 }
1197 else {
1198 continue; // keep looping
1199 }
1200 }
1201 }
1202 }
1203
1204 /**
1205 * Allocate available instances to latches in the allocation queue. Then
1206 * set _mayCreate to true for as many additional latches remaining in queue
1207 * as _maxActive allows for each key.
1208 */
1209 private void allocate() {
1210 boolean clearOldest = false;
1211
1212 synchronized (this) {
1213 if (isClosed()) return;
1214
1215 for (;;) {
1216 if (!_allocationQueue.isEmpty()) {
1217 // First use any objects in the pool to clear the queue
1218 Latch latch = (Latch) _allocationQueue.getFirst();
1219 ObjectQueue pool = (ObjectQueue)(_poolMap.get(latch.getkey()));
1220 if (null == pool) {
1221 pool = new ObjectQueue();
1222 _poolMap.put(latch.getkey(), pool);
1223 _poolList.add(latch.getkey());
1224 }
1225 latch.setPool(pool);
1226 if (!pool.queue.isEmpty()) {
1227 _allocationQueue.removeFirst();
1228 latch.setPair(
1229 (ObjectTimestampPair) pool.queue.removeFirst());
1230 pool.incrementInternalProcessingCount();
1231 _totalIdle--;
1232 synchronized (latch) {
1233 latch.notify();
1234 }
1235 // Next item in queue
1236 continue;
1237 }
1238
1239 // If there is a totalMaxActive and we are at the limit then
1240 // we have to make room
1241 if ((_maxTotal > 0) &&
1242 (_totalActive + _totalIdle + _totalInternalProcessing >= _maxTotal)) {
1243 clearOldest = true;
1244 break;
1245 }
1246
1247 // Second utilise any spare capacity to create new objects
1248 if ((_maxActive < 0 || pool.activeCount + pool.internalProcessingCount < _maxActive) &&
1249 (_maxTotal < 0 || _totalActive + _totalIdle + _totalInternalProcessing < _maxTotal)) {
1250 // allow new object to be created
1251 _allocationQueue.removeFirst();
1252 latch.setMayCreate(true);
1253 pool.incrementInternalProcessingCount();
1254 synchronized (latch) {
1255 latch.notify();
1256 }
1257 // Next item in queue
1258 continue;
1259 }
1260 }
1261 break;
1262 }
1263 }
1264
1265 if (clearOldest) {
1266 /* Clear oldest calls factory methods so it must be called from
1267 * outside the sync block.
1268 * It also needs to be outside the sync block as it calls
1269 * allocate(). If called inside the sync block, the call to
1270 * allocate() would be able to enter the sync block (since the
1271 * thread already has the lock) which may have unexpected,
1272 * unpleasant results.
1273 */
1274 clearOldest();
1275 }
1276 }
1277
1278 /**
1279 * Clears the pool, removing all pooled instances.
1280 */
1281 public void clear() {
1282 Map toDestroy = new HashMap();
1283 synchronized (this) {
1284 for (Iterator it = _poolMap.keySet().iterator(); it.hasNext();) {
1285 Object key = it.next();
1286 ObjectQueue pool = (ObjectQueue)_poolMap.get(key);
1287 // Copy objects to new list so pool.queue can be cleared inside
1288 // the sync
1289 List objects = new ArrayList();
1290 objects.addAll(pool.queue);
1291 toDestroy.put(key, objects);
1292 it.remove();
1293 _poolList.remove(key);
1294 _totalIdle = _totalIdle - pool.queue.size();
1295 _totalInternalProcessing =
1296 _totalInternalProcessing + pool.queue.size();
1297 pool.queue.clear();
1298 }
1299 }
1300 destroy(toDestroy);
1301 }
1302
1303 /**
1304 * Clears oldest 15% of objects in pool. The method sorts the
1305 * objects into a TreeMap and then iterates the first 15% for removal.
1306 *
1307 * @since Pool 1.3
1308 */
1309 public void clearOldest() {
1310 // Map of objects to destroy my key
1311 final Map toDestroy = new HashMap();
1312
1313 // build sorted map of idle objects
1314 final Map map = new TreeMap();
1315 synchronized (this) {
1316 for (Iterator keyiter = _poolMap.keySet().iterator(); keyiter.hasNext();) {
1317 final Object key = keyiter.next();
1318 final CursorableLinkedList list = ((ObjectQueue)_poolMap.get(key)).queue;
1319 for (Iterator it = list.iterator(); it.hasNext();) {
1320 // each item into the map uses the objectimestamppair object
1321 // as the key. It then gets sorted based on the timstamp field
1322 // each value in the map is the parent list it belongs in.
1323 map.put(it.next(), key);
1324 }
1325 }
1326
1327 // Now iterate created map and kill the first 15% plus one to account for zero
1328 Set setPairKeys = map.entrySet();
1329 int itemsToRemove = ((int) (map.size() * 0.15)) + 1;
1330
1331 Iterator iter = setPairKeys.iterator();
1332 while (iter.hasNext() && itemsToRemove > 0) {
1333 Map.Entry entry = (Map.Entry) iter.next();
1334 // kind of backwards on naming. In the map, each key is the objecttimestamppair
1335 // because it has the ordering with the timestamp value. Each value that the
1336 // key references is the key of the list it belongs to.
1337 Object key = entry.getValue();
1338 ObjectTimestampPair pairTimeStamp = (ObjectTimestampPair) entry.getKey();
1339 final CursorableLinkedList list =
1340 ((ObjectQueue)(_poolMap.get(key))).queue;
1341 list.remove(pairTimeStamp);
1342
1343 if (toDestroy.containsKey(key)) {
1344 ((List)toDestroy.get(key)).add(pairTimeStamp);
1345 } else {
1346 List listForKey = new ArrayList();
1347 listForKey.add(pairTimeStamp);
1348 toDestroy.put(key, listForKey);
1349 }
1350 // if that was the last object for that key, drop that pool
1351 if (list.isEmpty()) {
1352 _poolMap.remove(key);
1353 _poolList.remove(key);
1354 }
1355 _totalIdle--;
1356 _totalInternalProcessing++;
1357 itemsToRemove--;
1358 }
1359
1360 }
1361 destroy(toDestroy);
1362 }
1363
1364 /**
1365 * Clears the specified pool, removing all pooled instances corresponding to the given <code>key</code>.
1366 *
1367 * @param key the key to clear
1368 */
1369 public void clear(Object key) {
1370 Map toDestroy = new HashMap();
1371
1372 final ObjectQueue pool;
1373 synchronized (this) {
1374 pool = (ObjectQueue)(_poolMap.remove(key));
1375 if (pool == null) {
1376 return;
1377 } else {
1378 _poolList.remove(key);
1379 }
1380 // Copy objects to new list so pool.queue can be cleared inside
1381 // the sync
1382 List objects = new ArrayList();
1383 objects.addAll(pool.queue);
1384 toDestroy.put(key, objects);
1385 _totalIdle = _totalIdle - pool.queue.size();
1386 _totalInternalProcessing =
1387 _totalInternalProcessing + pool.queue.size();
1388 pool.queue.clear();
1389 }
1390 destroy(toDestroy);
1391 }
1392
1393 /**
1394 * Assuming Map<Object,Collection<ObjectTimestampPair>>, destroy all
1395 * ObjectTimestampPair.value
1396 *
1397 * @param m Map containing keyed pools to clear
1398 */
1399 private void destroy(Map m) {
1400 for (Iterator keys = m.keySet().iterator(); keys.hasNext();) {
1401 Object key = keys.next();
1402 Collection c = (Collection) m.get(key);
1403 for (Iterator it = c.iterator(); it.hasNext();) {
1404 try {
1405 _factory.destroyObject(
1406 key,((ObjectTimestampPair)(it.next())).value);
1407 } catch(Exception e) {
1408 // ignore error, keep destroying the rest
1409 } finally {
1410 synchronized(this) {
1411 _totalInternalProcessing--;
1412 allocate();
1413 }
1414 }
1415 }
1416
1417 }
1418 }
1419
1420 /**
1421 * Returns the total number of instances current borrowed from this pool but not yet returned.
1422 *
1423 * @return the total number of instances currently borrowed from this pool
1424 */
1425 public synchronized int getNumActive() {
1426 return _totalActive;
1427 }
1428
1429 /**
1430 * Returns the total number of instances currently idle in this pool.
1431 *
1432 * @return the total number of instances currently idle in this pool
1433 */
1434 public synchronized int getNumIdle() {
1435 return _totalIdle;
1436 }
1437
1438 /**
1439 * Returns the number of instances currently borrowed from but not yet returned
1440 * to the pool corresponding to the given <code>key</code>.
1441 *
1442 * @param key the key to query
1443 * @return the number of instances corresponding to the given <code>key</code> currently borrowed in this pool
1444 */
1445 public synchronized int getNumActive(Object key) {
1446 final ObjectQueue pool = (ObjectQueue)(_poolMap.get(key));
1447 return pool != null ? pool.activeCount : 0;
1448 }
1449
1450 /**
1451 * Returns the number of instances corresponding to the given <code>key</code> currently idle in this pool.
1452 *
1453 * @param key the key to query
1454 * @return the number of instances corresponding to the given <code>key</code> currently idle in this pool
1455 */
1456 public synchronized int getNumIdle(Object key) {
1457 final ObjectQueue pool = (ObjectQueue)(_poolMap.get(key));
1458 return pool != null ? pool.queue.size() : 0;
1459 }
1460
1461 /**
1462 * <p>Returns an object to a keyed pool.</p>
1463 *
1464 * <p>For the pool to function correctly, the object instance <strong>must</strong> have been borrowed
1465 * from the pool (under the same key) and not yet returned. Repeated <code>returnObject</code> calls on
1466 * the same object/key pair (with no <code>borrowObject</code> calls in between) will result in multiple
1467 * references to the object in the idle instance pool.</p>
1468 *
1469 * <p>If {@link #getMaxIdle() maxIdle} is set to a positive value and the number of idle instances under the given
1470 * key has reached this value, the returning instance is destroyed.</p>
1471 *
1472 * <p>If {@link #getTestOnReturn() testOnReturn} == true, the returning instance is validated before being returned
1473 * to the idle instance pool under the given key. In this case, if validation fails, the instance is destroyed.</p>
1474 *
1475 * @param key pool key
1476 * @param obj instance to return to the keyed pool
1477 * @throws Exception
1478 */
1479 public void returnObject(Object key, Object obj) throws Exception {
1480 try {
1481 addObjectToPool(key, obj, true);
1482 } catch (Exception e) {
1483 if (_factory != null) {
1484 try {
1485 _factory.destroyObject(key, obj);
1486 } catch (Exception e2) {
1487 // swallowed
1488 }
1489 // TODO: Correctness here depends on control in addObjectToPool.
1490 // These two methods should be refactored, removing the
1491 // "behavior flag", decrementNumActive, from addObjectToPool.
1492 ObjectQueue pool = (ObjectQueue) (_poolMap.get(key));
1493 if (pool != null) {
1494 synchronized(this) {
1495 pool.decrementActiveCount();
1496 allocate();
1497 }
1498 }
1499 }
1500 }
1501 }
1502
1503 /**
1504 * <p>Adds an object to the keyed pool.</p>
1505 *
1506 * <p>Validates the object if testOnReturn == true and passivates it before returning it to the pool.
1507 * if validation or passivation fails, or maxIdle is set and there is no room in the pool, the instance
1508 * is destroyed.</p>
1509 *
1510 * <p>Calls {@link #allocate()} on successful completion</p>
1511 *
1512 * @param key pool key
1513 * @param obj instance to add to the keyed pool
1514 * @param decrementNumActive whether or not to decrement the active count associated with the keyed pool
1515 * @throws Exception
1516 */
1517 private void addObjectToPool(Object key, Object obj,
1518 boolean decrementNumActive) throws Exception {
1519
1520 // if we need to validate this object, do so
1521 boolean success = true; // whether or not this object passed validation
1522 if (_testOnReturn && !_factory.validateObject(key, obj)) {
1523 success = false;
1524 } else {
1525 _factory.passivateObject(key, obj);
1526 }
1527
1528 boolean shouldDestroy = !success;
1529 ObjectQueue pool;
1530
1531 // Add instance to pool if there is room and it has passed validation
1532 // (if testOnreturn is set)
1533 synchronized (this) {
1534 // grab the pool (list) of objects associated with the given key
1535 pool = (ObjectQueue) (_poolMap.get(key));
1536 // if it doesn't exist, create it
1537 if (null == pool) {
1538 pool = new ObjectQueue();
1539 _poolMap.put(key, pool);
1540 _poolList.add(key);
1541 }
1542 if (isClosed()) {
1543 shouldDestroy = true;
1544 } else {
1545 // if there's no space in the pool, flag the object for destruction
1546 // else if we passivated successfully, return it to the pool
1547 if (_maxIdle >= 0 && (pool.queue.size() >= _maxIdle)) {
1548 shouldDestroy = true;
1549 } else if (success) {
1550 // borrowObject always takes the first element from the queue,
1551 // so for LIFO, push on top, FIFO add to end
1552 if (_lifo) {
1553 pool.queue.addFirst(new ObjectTimestampPair(obj));
1554 } else {
1555 pool.queue.addLast(new ObjectTimestampPair(obj));
1556 }
1557 _totalIdle++;
1558 if (decrementNumActive) {
1559 pool.decrementActiveCount();
1560 }
1561 allocate();
1562 }
1563 }
1564 }
1565
1566 // Destroy the instance if necessary
1567 if (shouldDestroy) {
1568 try {
1569 _factory.destroyObject(key, obj);
1570 } catch(Exception e) {
1571 // ignored?
1572 }
1573 // Decrement active count *after* destroy if applicable
1574 if (decrementNumActive) {
1575 synchronized(this) {
1576 pool.decrementActiveCount();
1577 allocate();
1578 }
1579 }
1580 }
1581 }
1582
1583 /**
1584 * <p>Invalidates the object instance associated with the given key. Decrements the active count
1585 * associated with the given keyed pool and destroys the instance.</p>
1586 *
1587 * @param key pool key
1588 * @param obj instance to invalidate
1589 * @throws Exception if an exception occurs destroying the object
1590 */
1591 public void invalidateObject(Object key, Object obj) throws Exception {
1592 try {
1593 _factory.destroyObject(key, obj);
1594 } finally {
1595 synchronized (this) {
1596 ObjectQueue pool = (ObjectQueue) (_poolMap.get(key));
1597 if (null == pool) {
1598 pool = new ObjectQueue();
1599 _poolMap.put(key, pool);
1600 _poolList.add(key);
1601 }
1602 pool.decrementActiveCount();
1603 allocate(); // _totalActive has changed
1604 }
1605 }
1606 }
1607
1608 /**
1609 * Create an object using the {@link KeyedPoolableObjectFactory#makeObject factory},
1610 * passivate it, and then place it in the idle object pool.
1611 * <code>addObject</code> is useful for "pre-loading" a pool with idle objects.
1612 *
1613 * @param key the key a new instance should be added to
1614 * @throws Exception when {@link KeyedPoolableObjectFactory#makeObject} fails.
1615 * @throws IllegalStateException when no {@link #setFactory factory} has been set or after {@link #close} has been
1616 * called on this pool.
1617 */
1618 public void addObject(Object key) throws Exception {
1619 assertOpen();
1620 if (_factory == null) {
1621 throw new IllegalStateException("Cannot add objects without a factory.");
1622 }
1623 Object obj = _factory.makeObject(key);
1624 try {
1625 assertOpen();
1626 addObjectToPool(key, obj, false);
1627 } catch (IllegalStateException ex) { // Pool closed
1628 try {
1629 _factory.destroyObject(key, obj);
1630 } catch (Exception ex2) {
1631 // swallow
1632 }
1633 throw ex;
1634 }
1635 }
1636
1637 /**
1638 * Registers a key for pool control.
1639 *
1640 * If <code>populateImmediately</code> is <code>true</code> and
1641 * <code>minIdle > 0,</code> the pool under the given key will be
1642 * populated immediately with <code>minIdle</code> idle instances.
1643 *
1644 * @param key - The key to register for pool control.
1645 * @param populateImmediately - If this is <code>true</code>, the pool
1646 * will be populated immediately.
1647 * @since Pool 1.3
1648 */
1649 public synchronized void preparePool(Object key, boolean populateImmediately) {
1650 ObjectQueue pool = (ObjectQueue)(_poolMap.get(key));
1651 if (null == pool) {
1652 pool = new ObjectQueue();
1653 _poolMap.put(key,pool);
1654 _poolList.add(key);
1655 }
1656
1657 if (populateImmediately) {
1658 try {
1659 // Create the pooled objects
1660 ensureMinIdle(key);
1661 }
1662 catch (Exception e) {
1663 //Do nothing
1664 }
1665 }
1666 }
1667
1668 /**
1669 * Closes the keyed object pool. Once the pool is closed, {@link #borrowObject(Object)}
1670 * will fail with IllegalStateException, but {@link #returnObject(Object, Object)} and
1671 * {@link #invalidateObject(Object, Object)} will continue to work. This method does not
1672 * {@link #clear()} the pool. The method is idempotent - that is, it is OK to call it on a closed
1673 * pool.
1674 *
1675 * @throws Exception
1676 */
1677 public void close() throws Exception {
1678 super.close();
1679 synchronized (this) {
1680 clear();
1681 if (null != _evictionCursor) {
1682 _evictionCursor.close();
1683 _evictionCursor = null;
1684 }
1685 if (null != _evictionKeyCursor) {
1686 _evictionKeyCursor.close();
1687 _evictionKeyCursor = null;
1688 }
1689 startEvictor(-1L);
1690 }
1691 }
1692
1693 /**
1694 * <p>Sets the keyed poolable object factory associated with this pool.</p>
1695 *
1696 * <p>If this method is called when objects are checked out of any of the keyed pools,
1697 * an IllegalStateException is thrown. Calling this method also has the side effect of
1698 * destroying any idle instances in existing keyed pools.</p>
1699 *
1700 * @param factory KeyedPoolableObjectFactory to use when creating keyed object pool instances
1701 * @throws IllegalStateException if there are active (checked out) instances associated with this keyed object pool
1702 */
1703 public void setFactory(KeyedPoolableObjectFactory factory) throws IllegalStateException {
1704 Map toDestroy = new HashMap();
1705 synchronized (this) {
1706 assertOpen();
1707 if (0 < getNumActive()) {
1708 throw new IllegalStateException("Objects are already active");
1709 } else {
1710 for (Iterator it = _poolMap.keySet().iterator(); it.hasNext();) {
1711 Object key = it.next();
1712 ObjectQueue pool = (ObjectQueue)_poolMap.get(key);
1713 if (pool != null) {
1714 // Copy objects to new list so pool.queue can be cleared
1715 // inside the sync
1716 List objects = new ArrayList();
1717 objects.addAll(pool.queue);
1718 toDestroy.put(key, objects);
1719 it.remove();
1720 _poolList.remove(key);
1721 _totalIdle = _totalIdle - pool.queue.size();
1722 _totalInternalProcessing =
1723 _totalInternalProcessing + pool.queue.size();
1724 pool.queue.clear();
1725 }
1726 }
1727 _factory = factory;
1728 }
1729 }
1730 destroy(toDestroy);
1731 }
1732
1733 /**
1734 * <p>Perform <code>numTests</code> idle object eviction tests, evicting
1735 * examined objects that meet the criteria for eviction. If
1736 * <code>testWhileIdle</code> is true, examined objects are validated
1737 * when visited (and removed if invalid); otherwise only objects that
1738 * have been idle for more than <code>minEvicableIdletimeMillis</code>
1739 * are removed.</p>
1740 *
1741 * <p>Successive activations of this method examine objects in keyed pools
1742 * in sequence, cycling through the keys and examining objects in
1743 * oldest-to-youngest order within the keyed pools.</p>
1744 *
1745 * @throws Exception when there is a problem evicting idle objects.
1746 */
1747 public void evict() throws Exception {
1748 Object key = null;
1749 boolean testWhileIdle;
1750 long minEvictableIdleTimeMillis;
1751
1752 synchronized (this) {
1753 // Get local copy of current config. Can't sync when used later as
1754 // it can result in a deadlock. Has the added advantage that config
1755 // is consistent for entire method execution
1756 testWhileIdle = _testWhileIdle;
1757 minEvictableIdleTimeMillis = _minEvictableIdleTimeMillis;
1758
1759 // Initialize key to last key value
1760 if (_evictionKeyCursor != null &&
1761 _evictionKeyCursor._lastReturned != null) {
1762 key = _evictionKeyCursor._lastReturned.value();
1763 }
1764 }
1765
1766 for (int i=0, m=getNumTests(); i<m; i++) {
1767 final ObjectTimestampPair pair;
1768 synchronized (this) {
1769 // make sure pool map is not empty; otherwise do nothing
1770 if (_poolMap == null || _poolMap.size() == 0) {
1771 continue;
1772 }
1773
1774 // if we don't have a key cursor, then create one
1775 if (null == _evictionKeyCursor) {
1776 resetEvictionKeyCursor();
1777 key = null;
1778 }
1779
1780 // if we don't have an object cursor, create one
1781 if (null == _evictionCursor) {
1782 // if the _evictionKeyCursor has a next value, use this key
1783 if (_evictionKeyCursor.hasNext()) {
1784 key = _evictionKeyCursor.next();
1785 resetEvictionObjectCursor(key);
1786 } else {
1787 // Reset the key cursor and try again
1788 resetEvictionKeyCursor();
1789 if (_evictionKeyCursor != null) {
1790 if (_evictionKeyCursor.hasNext()) {
1791 key = _evictionKeyCursor.next();
1792 resetEvictionObjectCursor(key);
1793 }
1794 }
1795 }
1796 }
1797
1798 if (_evictionCursor == null) {
1799 continue; // should never happen; do nothing
1800 }
1801
1802 // If eviction cursor is exhausted, try to move
1803 // to the next key and reset
1804 if ((_lifo && !_evictionCursor.hasPrevious()) ||
1805 (!_lifo && !_evictionCursor.hasNext())) {
1806 if (_evictionKeyCursor != null) {
1807 if (_evictionKeyCursor.hasNext()) {
1808 key = _evictionKeyCursor.next();
1809 resetEvictionObjectCursor(key);
1810 } else { // Need to reset Key cursor
1811 resetEvictionKeyCursor();
1812 if (_evictionKeyCursor != null) {
1813 if (_evictionKeyCursor.hasNext()) {
1814 key = _evictionKeyCursor.next();
1815 resetEvictionObjectCursor(key);
1816 }
1817 }
1818 }
1819 }
1820 }
1821
1822 if ((_lifo && !_evictionCursor.hasPrevious()) ||
1823 (!_lifo && !_evictionCursor.hasNext())) {
1824 continue; // reset failed, do nothing
1825 }
1826
1827 // if LIFO and the _evictionCursor has a previous object,
1828 // or FIFO and _evictionCursor has a next object, test it
1829 pair = _lifo ?
1830 (ObjectTimestampPair) _evictionCursor.previous() :
1831 (ObjectTimestampPair) _evictionCursor.next();
1832 _evictionCursor.remove();
1833 _totalIdle--;
1834 _totalInternalProcessing++;
1835 }
1836
1837 boolean removeObject=false;
1838 if ((minEvictableIdleTimeMillis > 0) &&
1839 (System.currentTimeMillis() - pair.tstamp >
1840 minEvictableIdleTimeMillis)) {
1841 removeObject=true;
1842 }
1843 if (testWhileIdle && removeObject == false) {
1844 boolean active = false;
1845 try {
1846 _factory.activateObject(key,pair.value);
1847 active = true;
1848 } catch(Exception e) {
1849 removeObject=true;
1850 }
1851 if (active) {
1852 if (!_factory.validateObject(key,pair.value)) {
1853 removeObject=true;
1854 } else {
1855 try {
1856 _factory.passivateObject(key,pair.value);
1857 } catch(Exception e) {
1858 removeObject=true;
1859 }
1860 }
1861 }
1862 }
1863
1864 if (removeObject) {
1865 try {
1866 _factory.destroyObject(key, pair.value);
1867 } catch(Exception e) {
1868 // ignored
1869 } finally {
1870 // Do not remove the key from the _poolList or _poolmap,
1871 // even if the list stored in the _poolMap for this key is
1872 // empty when minIdle > 0.
1873 //
1874 // Otherwise if it was the last object for that key,
1875 // drop that pool
1876 if (_minIdle == 0) {
1877 synchronized (this) {
1878 ObjectQueue objectQueue =
1879 (ObjectQueue)_poolMap.get(key);
1880 if (objectQueue != null &&
1881 objectQueue.queue.isEmpty()) {
1882 _poolMap.remove(key);
1883 _poolList.remove(key);
1884 }
1885 }
1886 }
1887 }
1888 }
1889 synchronized (this) {
1890 if (!removeObject) {
1891 _evictionCursor.add(pair);
1892 _totalIdle++;
1893 if (_lifo) {
1894 // Skip over the element we just added back
1895 _evictionCursor.previous();
1896 }
1897 }
1898 _totalInternalProcessing--;
1899 }
1900 }
1901 }
1902
1903 /**
1904 * Resets the eviction key cursor and closes any
1905 * associated eviction object cursor
1906 */
1907 private void resetEvictionKeyCursor() {
1908 if (_evictionKeyCursor != null) {
1909 _evictionKeyCursor.close();
1910 }
1911 _evictionKeyCursor = _poolList.cursor();
1912 if (null != _evictionCursor) {
1913 _evictionCursor.close();
1914 _evictionCursor = null;
1915 }
1916 }
1917
1918 /**
1919 * Resets the eviction object cursor for the given key
1920 *
1921 * @param key eviction key
1922 */
1923 private void resetEvictionObjectCursor(Object key) {
1924 if (_evictionCursor != null) {
1925 _evictionCursor.close();
1926 }
1927 if (_poolMap == null) {
1928 return;
1929 }
1930 ObjectQueue pool = (ObjectQueue) (_poolMap.get(key));
1931 if (pool != null) {
1932 CursorableLinkedList queue = pool.queue;
1933 _evictionCursor = queue.cursor(_lifo ? queue.size() : 0);
1934 }
1935 }
1936
1937 /**
1938 * Iterates through all the known keys and creates any necessary objects to maintain
1939 * the minimum level of pooled objects.
1940 * @see #getMinIdle
1941 * @see #setMinIdle
1942 * @throws Exception If there was an error whilst creating the pooled objects.
1943 */
1944 private void ensureMinIdle() throws Exception {
1945 //Check if should sustain the pool
1946 if (_minIdle > 0) {
1947 Object[] keysCopy;
1948 synchronized(this) {
1949 // Get the current set of keys
1950 keysCopy = _poolMap.keySet().toArray();
1951 }
1952
1953 // Loop through all elements in _poolList
1954 // Find out the total number of max active and max idle for that class
1955 // If the number is less than the minIdle, do creation loop to boost numbers
1956 for (int i=0; i < keysCopy.length; i++) {
1957 //Get the next key to process
1958 ensureMinIdle(keysCopy[i]);
1959 }
1960 }
1961 }
1962
1963 /**
1964 * Re-creates any needed objects to maintain the minimum levels of
1965 * pooled objects for the specified key.
1966 *
1967 * This method uses {@link #calculateDefecit} to calculate the number
1968 * of objects to be created. {@link #calculateDefecit} can be overridden to
1969 * provide a different method of calculating the number of objects to be
1970 * created.
1971 * @param key The key to process
1972 * @throws Exception If there was an error whilst creating the pooled objects
1973 */
1974 private void ensureMinIdle(Object key) throws Exception {
1975 // Calculate current pool objects
1976 ObjectQueue pool;
1977 synchronized(this) {
1978 pool = (ObjectQueue)(_poolMap.get(key));
1979 }
1980 if (pool == null) {
1981 return;
1982 }
1983
1984 // this method isn't synchronized so the
1985 // calculateDeficit is done at the beginning
1986 // as a loop limit and a second time inside the loop
1987 // to stop when another thread already returned the
1988 // needed objects
1989 int objectDeficit = calculateDefecit(pool, false);
1990
1991 for (int i = 0; i < objectDeficit && calculateDefecit(pool, true) > 0; i++) {
1992 try {
1993 addObject(key);
1994 } finally {
1995 synchronized (this) {
1996 pool.decrementInternalProcessingCount();
1997 allocate();
1998 }
1999 }
2000 }
2001 }
2002
2003 //--- non-public methods ----------------------------------------
2004
2005 /**
2006 * Start the eviction thread or service, or when
2007 * <code>delay</code> is non-positive, stop it
2008 * if it is already running.
2009 *
2010 * @param delay milliseconds between evictor runs.
2011 */
2012 protected synchronized void startEvictor(long delay) {
2013 if (null != _evictor) {
2014 EvictionTimer.cancel(_evictor);
2015 _evictor = null;
2016 }
2017 if (delay > 0) {
2018 _evictor = new Evictor();
2019 EvictionTimer.schedule(_evictor, delay, delay);
2020 }
2021 }
2022
2023 synchronized String debugInfo() {
2024 StringBuffer buf = new StringBuffer();
2025 buf.append("Active: ").append(getNumActive()).append("\n");
2026 buf.append("Idle: ").append(getNumIdle()).append("\n");
2027 Iterator it = _poolMap.keySet().iterator();
2028 while (it.hasNext()) {
2029 buf.append("\t").append(_poolMap.get(it.next())).append("\n");
2030 }
2031 return buf.toString();
2032 }
2033
2034 private synchronized int getNumTests() {
2035 if (_numTestsPerEvictionRun >= 0) {
2036 return _numTestsPerEvictionRun;
2037 } else {
2038 return(int)(Math.ceil(_totalIdle/Math.abs((double)_numTestsPerEvictionRun)));
2039 }
2040 }
2041
2042 /**
2043 * This returns the number of objects to create during the pool
2044 * sustain cycle. This will ensure that the minimum number of idle
2045 * instances is maintained without going past the maxActive value.
2046 *
2047 * @param pool the ObjectPool to calculate the deficit for
2048 * @param incrementInternal - Should the count of objects currently under
2049 * some form of internal processing be
2050 * incremented?
2051 * @return The number of objects to be created
2052 */
2053 private synchronized int calculateDefecit(ObjectQueue pool,
2054 boolean incrementInternal) {
2055 int objectDefecit = 0;
2056
2057 //Calculate no of objects needed to be created, in order to have
2058 //the number of pooled objects < maxActive();
2059 objectDefecit = getMinIdle() - pool.queue.size();
2060 if (getMaxActive() > 0) {
2061 int growLimit = Math.max(0, getMaxActive() - pool.activeCount - pool.queue.size() - pool.internalProcessingCount);
2062 objectDefecit = Math.min(objectDefecit, growLimit);
2063 }
2064
2065 // Take the maxTotal limit into account
2066 if (getMaxTotal() > 0) {
2067 int growLimit = Math.max(0, getMaxTotal() - getNumActive() - getNumIdle() - _totalInternalProcessing);
2068 objectDefecit = Math.min(objectDefecit, growLimit);
2069 }
2070
2071 if (incrementInternal && objectDefecit > 0) {
2072 pool.incrementInternalProcessingCount();
2073 }
2074 return objectDefecit;
2075 }
2076
2077 //--- inner classes ----------------------------------------------
2078
2079 /**
2080 * A "struct" that keeps additional information about the actual queue of pooled objects.
2081 */
2082 private class ObjectQueue {
2083 /** Number of instances checked out to clients from this queue */
2084 private int activeCount = 0;
2085
2086 /** Idle instance queue */
2087 private final CursorableLinkedList queue = new CursorableLinkedList();
2088
2089 /** Number of instances in process of being created */
2090 private int internalProcessingCount = 0;
2091
2092 /** Increment the active count for this queue */
2093 void incrementActiveCount() {
2094 synchronized (GenericKeyedObjectPool.this) {
2095 _totalActive++;
2096 }
2097 activeCount++;
2098 }
2099
2100 /** Decrement the active count for this queue */
2101 void decrementActiveCount() {
2102 synchronized (GenericKeyedObjectPool.this) {
2103 _totalActive--;
2104 }
2105 if (activeCount > 0) {
2106 activeCount--;
2107 }
2108 }
2109
2110 /** Record the fact that one more instance is queued for creation */
2111 void incrementInternalProcessingCount() {
2112 synchronized (GenericKeyedObjectPool.this) {
2113 _totalInternalProcessing++;
2114 }
2115 internalProcessingCount++;
2116 }
2117
2118 /** Decrement the number of instances in process of being created */
2119 void decrementInternalProcessingCount() {
2120 synchronized (GenericKeyedObjectPool.this) {
2121 _totalInternalProcessing--;
2122 }
2123 internalProcessingCount--;
2124 }
2125 }
2126
2127 /**
2128 * A simple "struct" encapsulating an object instance and a timestamp.
2129 *
2130 * Implements Comparable, objects are sorted from old to new.
2131 *
2132 * This is also used by {@link GenericObjectPool}.
2133 */
2134 static class ObjectTimestampPair implements Comparable {
2135
2136 /** Object instance */
2137 Object value;
2138
2139 /** timestamp */
2140 long tstamp;
2141
2142 /**
2143 * Create a new ObjectTimestampPair using the given object and the current system time.
2144 * @param val object instance
2145 */
2146 ObjectTimestampPair(Object val) {
2147 this(val, System.currentTimeMillis());
2148 }
2149
2150 /**
2151 * Create a new ObjectTimeStampPair using the given object and timestamp value.
2152 * @param val object instance
2153 * @param time long representation of timestamp
2154 */
2155 ObjectTimestampPair(Object val, long time) {
2156 value = val;
2157 tstamp = time;
2158 }
2159
2160 /**
2161 * Returns a string representation.
2162 *
2163 * @return String representing this ObjectTimestampPair
2164 */
2165 public String toString() {
2166 return value + ";" + tstamp;
2167 }
2168
2169 /**
2170 * Compares this to another object by casting the argument to an
2171 * ObjectTimestampPair.
2172 *
2173 * @param obj object to cmpare
2174 * @return result of comparison
2175 */
2176 public int compareTo(Object obj) {
2177 return compareTo((ObjectTimestampPair) obj);
2178 }
2179
2180 /**
2181 * Compares this to another ObjectTimestampPair, using the timestamp as basis for comparison.
2182 * Implementation is consistent with equals.
2183 *
2184 * @param other object to compare
2185 * @return result of comparison
2186 */
2187 public int compareTo(ObjectTimestampPair other) {
2188 final long tstampdiff = this.tstamp - other.tstamp;
2189 if (tstampdiff == 0) {
2190 // make sure the natural ordering is consistent with equals
2191 // see java.lang.Comparable Javadocs
2192 return System.identityHashCode(this) - System.identityHashCode(other);
2193 } else {
2194 // handle int overflow
2195 return (int)Math.min(Math.max(tstampdiff, Integer.MIN_VALUE), Integer.MAX_VALUE);
2196 }
2197 }
2198 }
2199
2200 /**
2201 * The idle object evictor {@link TimerTask}.
2202 * @see GenericKeyedObjectPool#setTimeBetweenEvictionRunsMillis
2203 */
2204 private class Evictor extends TimerTask {
2205 public void run() {
2206 //Evict from the pool
2207 try {
2208 evict();
2209 } catch(Exception e) {
2210 // ignored
2211 } catch(OutOfMemoryError oome) {
2212 // Log problem but give evictor thread a chance to continue in
2213 // case error is recoverable
2214 oome.printStackTrace(System.err);
2215 }
2216 //Re-create idle instances.
2217 try {
2218 ensureMinIdle();
2219 } catch (Exception e) {
2220 // ignored
2221 }
2222 }
2223 }
2224
2225 /**
2226 * A simple "struct" encapsulating the
2227 * configuration information for a <code>GenericKeyedObjectPool</code>.
2228 * @see GenericKeyedObjectPool#GenericKeyedObjectPool(KeyedPoolableObjectFactory,GenericKeyedObjectPool.Config)
2229 * @see GenericKeyedObjectPool#setConfig
2230 */
2231 public static class Config {
2232 /**
2233 * @see GenericKeyedObjectPool#setMaxIdle
2234 */
2235 public int maxIdle = GenericKeyedObjectPool.DEFAULT_MAX_IDLE;
2236 /**
2237 * @see GenericKeyedObjectPool#setMaxActive
2238 */
2239 public int maxActive = GenericKeyedObjectPool.DEFAULT_MAX_ACTIVE;
2240 /**
2241 * @see GenericKeyedObjectPool#setMaxTotal
2242 */
2243 public int maxTotal = GenericKeyedObjectPool.DEFAULT_MAX_TOTAL;
2244 /**
2245 * @see GenericKeyedObjectPool#setMinIdle
2246 */
2247 public int minIdle = GenericKeyedObjectPool.DEFAULT_MIN_IDLE;
2248 /**
2249 * @see GenericKeyedObjectPool#setMaxWait
2250 */
2251 public long maxWait = GenericKeyedObjectPool.DEFAULT_MAX_WAIT;
2252 /**
2253 * @see GenericKeyedObjectPool#setWhenExhaustedAction
2254 */
2255 public byte whenExhaustedAction = GenericKeyedObjectPool.DEFAULT_WHEN_EXHAUSTED_ACTION;
2256 /**
2257 * @see GenericKeyedObjectPool#setTestOnBorrow
2258 */
2259 public boolean testOnBorrow = GenericKeyedObjectPool.DEFAULT_TEST_ON_BORROW;
2260 /**
2261 * @see GenericKeyedObjectPool#setTestOnReturn
2262 */
2263 public boolean testOnReturn = GenericKeyedObjectPool.DEFAULT_TEST_ON_RETURN;
2264 /**
2265 * @see GenericKeyedObjectPool#setTestWhileIdle
2266 */
2267 public boolean testWhileIdle = GenericKeyedObjectPool.DEFAULT_TEST_WHILE_IDLE;
2268 /**
2269 * @see GenericKeyedObjectPool#setTimeBetweenEvictionRunsMillis
2270 */
2271 public long timeBetweenEvictionRunsMillis = GenericKeyedObjectPool.DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS;
2272 /**
2273 * @see GenericKeyedObjectPool#setNumTestsPerEvictionRun
2274 */
2275 public int numTestsPerEvictionRun = GenericKeyedObjectPool.DEFAULT_NUM_TESTS_PER_EVICTION_RUN;
2276 /**
2277 * @see GenericKeyedObjectPool#setMinEvictableIdleTimeMillis
2278 */
2279 public long minEvictableIdleTimeMillis = GenericKeyedObjectPool.DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS;
2280 /**
2281 * @see GenericKeyedObjectPool#setLifo
2282 */
2283 public boolean lifo = GenericKeyedObjectPool.DEFAULT_LIFO;
2284 }
2285
2286 /**
2287 * Latch used to control allocation order of objects to threads to ensure
2288 * fairness. That is, objects are allocated to threads in the order that threads
2289 * request objects.
2290 *
2291 * @since 1.5
2292 */
2293 private static final class Latch {
2294
2295 /** key of associated pool */
2296 private final Object _key;
2297
2298 /** keyed pool associated with this latch */
2299 private ObjectQueue _pool;
2300
2301 /** holds an ObjectTimestampPair when this latch has been allocated an instance */
2302 private ObjectTimestampPair _pair;
2303
2304 /** indicates that this latch can create an instance */
2305 private boolean _mayCreate = false;
2306
2307 /**
2308 * Create a latch with the given key
2309 * @param key key of the pool associated with this latch
2310 */
2311 private Latch(Object key) {
2312 _key = key;
2313 }
2314
2315 /**
2316 * Retuns the key of the associated pool
2317 * @return associated pool key
2318 */
2319 private synchronized Object getkey() {
2320 return _key;
2321 }
2322
2323 /**
2324 * Returns the pool associated with this latch
2325 * @return pool
2326 */
2327 private synchronized ObjectQueue getPool() {
2328 return _pool;
2329 }
2330
2331 /**
2332 * Sets the pool associated with this latch
2333 * @param pool the pool
2334 */
2335 private synchronized void setPool(ObjectQueue pool) {
2336 _pool = pool;
2337 }
2338
2339 /**
2340 * Gets the ObjectTimestampPair allocated to this latch.
2341 * Returns null if this latch does not have an instance allocated to it.
2342 * @return the associated ObjectTimestampPair
2343 */
2344 private synchronized ObjectTimestampPair getPair() {
2345 return _pair;
2346 }
2347
2348 /**
2349 * Allocate an ObjectTimestampPair to this latch.
2350 * @param pair ObjectTimestampPair on this latch
2351 */
2352 private synchronized void setPair(ObjectTimestampPair pair) {
2353 _pair = pair;
2354 }
2355
2356 /**
2357 * Whether or not this latch can create an instance
2358 * @return true if this latch has an instance creation permit
2359 */
2360 private synchronized boolean mayCreate() {
2361 return _mayCreate;
2362 }
2363
2364 /**
2365 * Sets the mayCreate property
2366 *
2367 * @param mayCreate true means this latch can create an instance
2368 */
2369 private synchronized void setMayCreate(boolean mayCreate) {
2370 _mayCreate = mayCreate;
2371 }
2372
2373 /**
2374 * Reset the latch data. Used when an allocation fails and the latch
2375 * needs to be re-added to the queue.
2376 */
2377 private synchronized void reset() {
2378 _pair = null;
2379 _mayCreate = false;
2380 }
2381 }
2382
2383 //--- protected attributes ---------------------------------------
2384
2385 /**
2386 * The cap on the number of idle instances in the pool.
2387 * @see #setMaxIdle
2388 * @see #getMaxIdle
2389 */
2390 private int _maxIdle = DEFAULT_MAX_IDLE;
2391
2392 /**
2393 * The minimum no of idle objects to keep in the pool.
2394 * @see #setMinIdle
2395 * @see #getMinIdle
2396 */
2397 private int _minIdle = DEFAULT_MIN_IDLE;
2398
2399 /**
2400 * The cap on the number of active instances from the pool.
2401 * @see #setMaxActive
2402 * @see #getMaxActive
2403 */
2404 private int _maxActive = DEFAULT_MAX_ACTIVE;
2405
2406 /**
2407 * The cap on the total number of instances from the pool if non-positive.
2408 * @see #setMaxTotal
2409 * @see #getMaxTotal
2410 */
2411 private int _maxTotal = DEFAULT_MAX_TOTAL;
2412
2413 /**
2414 * The maximum amount of time (in millis) the
2415 * {@link #borrowObject} method should block before throwing
2416 * an exception when the pool is exhausted and the
2417 * {@link #getWhenExhaustedAction "when exhausted" action} is
2418 * {@link #WHEN_EXHAUSTED_BLOCK}.
2419 *
2420 * When less than or equal to 0, the {@link #borrowObject} method
2421 * may block indefinitely.
2422 *
2423 * @see #setMaxWait
2424 * @see #getMaxWait
2425 * @see #WHEN_EXHAUSTED_BLOCK
2426 * @see #setWhenExhaustedAction
2427 * @see #getWhenExhaustedAction
2428 */
2429 private long _maxWait = DEFAULT_MAX_WAIT;
2430
2431 /**
2432 * The action to take when the {@link #borrowObject} method
2433 * is invoked when the pool is exhausted (the maximum number
2434 * of "active" objects has been reached).
2435 *
2436 * @see #WHEN_EXHAUSTED_BLOCK
2437 * @see #WHEN_EXHAUSTED_FAIL
2438 * @see #WHEN_EXHAUSTED_GROW
2439 * @see #DEFAULT_WHEN_EXHAUSTED_ACTION
2440 * @see #setWhenExhaustedAction
2441 * @see #getWhenExhaustedAction
2442 */
2443 private byte _whenExhaustedAction = DEFAULT_WHEN_EXHAUSTED_ACTION;
2444
2445 /**
2446 * When <code>true</code>, objects will be
2447 * {@link org.apache.commons.pool.PoolableObjectFactory#validateObject validated}
2448 * before being returned by the {@link #borrowObject}
2449 * method. If the object fails to validate,
2450 * it will be dropped from the pool, and we will attempt
2451 * to borrow another.
2452 *
2453 * @see #setTestOnBorrow
2454 * @see #getTestOnBorrow
2455 */
2456 private volatile boolean _testOnBorrow = DEFAULT_TEST_ON_BORROW;
2457
2458 /**
2459 * When <code>true</code>, objects will be
2460 * {@link org.apache.commons.pool.PoolableObjectFactory#validateObject validated}
2461 * before being returned to the pool within the
2462 * {@link #returnObject}.
2463 *
2464 * @see #getTestOnReturn
2465 * @see #setTestOnReturn
2466 */
2467 private volatile boolean _testOnReturn = DEFAULT_TEST_ON_RETURN;
2468
2469 /**
2470 * When <code>true</code>, objects will be
2471 * {@link org.apache.commons.pool.PoolableObjectFactory#validateObject validated}
2472 * by the idle object evictor (if any). If an object
2473 * fails to validate, it will be dropped from the pool.
2474 *
2475 * @see #setTestWhileIdle
2476 * @see #getTestWhileIdle
2477 * @see #getTimeBetweenEvictionRunsMillis
2478 * @see #setTimeBetweenEvictionRunsMillis
2479 */
2480 private boolean _testWhileIdle = DEFAULT_TEST_WHILE_IDLE;
2481
2482 /**
2483 * The number of milliseconds to sleep between runs of the
2484 * idle object evictor thread.
2485 * When non-positive, no idle object evictor thread will be
2486 * run.
2487 *
2488 * @see #setTimeBetweenEvictionRunsMillis
2489 * @see #getTimeBetweenEvictionRunsMillis
2490 */
2491 private long _timeBetweenEvictionRunsMillis = DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS;
2492
2493 /**
2494 * The number of objects to examine during each run of the
2495 * idle object evictor thread (if any).
2496 * <p>
2497 * When a negative value is supplied, <code>ceil({@link #getNumIdle})/abs({@link #getNumTestsPerEvictionRun})</code>
2498 * tests will be run. I.e., when the value is <code>-n</code>, roughly one <code>n</code>th of the
2499 * idle objects will be tested per run.
2500 *
2501 * @see #setNumTestsPerEvictionRun
2502 * @see #getNumTestsPerEvictionRun
2503 * @see #getTimeBetweenEvictionRunsMillis
2504 * @see #setTimeBetweenEvictionRunsMillis
2505 */
2506 private int _numTestsPerEvictionRun = DEFAULT_NUM_TESTS_PER_EVICTION_RUN;
2507
2508 /**
2509 * The minimum amount of time an object may sit idle in the pool
2510 * before it is eligible for eviction by the idle object evictor
2511 * (if any).
2512 * When non-positive, no objects will be evicted from the pool
2513 * due to idle time alone.
2514 *
2515 * @see #setMinEvictableIdleTimeMillis
2516 * @see #getMinEvictableIdleTimeMillis
2517 * @see #getTimeBetweenEvictionRunsMillis
2518 * @see #setTimeBetweenEvictionRunsMillis
2519 */
2520 private long _minEvictableIdleTimeMillis = DEFAULT_MIN_EVICTABLE_IDLE_TIME_MILLIS;
2521
2522 /** My hash of pools (ObjectQueue). */
2523 private Map _poolMap = null;
2524
2525 /** The total number of active instances. */
2526 private int _totalActive = 0;
2527
2528 /** The total number of idle instances. */
2529 private int _totalIdle = 0;
2530
2531 /**
2532 * The number of objects subject to some form of internal processing
2533 * (usually creation or destruction) that should be included in the total
2534 * number of objects but are neither active nor idle.
2535 */
2536 private int _totalInternalProcessing = 0;
2537
2538 /** My {@link KeyedPoolableObjectFactory}. */
2539 private KeyedPoolableObjectFactory _factory = null;
2540
2541 /**
2542 * My idle object eviction {@link TimerTask}, if any.
2543 */
2544 private Evictor _evictor = null;
2545
2546 /**
2547 * A cursorable list of my pools.
2548 * @see GenericKeyedObjectPool.Evictor#run
2549 */
2550 private CursorableLinkedList _poolList = null;
2551
2552 /** Eviction cursor (over instances within-key) */
2553 private CursorableLinkedList.Cursor _evictionCursor = null;
2554
2555 /** Eviction cursor (over keys) */
2556 private CursorableLinkedList.Cursor _evictionKeyCursor = null;
2557
2558 /** Whether or not the pools behave as LIFO queues (last in first out) */
2559 private boolean _lifo = DEFAULT_LIFO;
2560
2561 /**
2562 * Used to track the order in which threads call {@link #borrowObject()} so
2563 * that objects can be allocated in the order in which the threads requested
2564 * them.
2565 */
2566 private LinkedList _allocationQueue = new LinkedList();
2567
2568 }