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.configuration;
019
020 import java.util.ArrayList;
021 import java.util.Collection;
022 import java.util.Iterator;
023 import java.util.List;
024 import java.util.Map;
025
026 import org.apache.commons.collections.map.LinkedMap;
027
028 /**
029 * Basic configuration class. Stores the configuration data but does not
030 * provide any load or save functions. If you want to load your Configuration
031 * from a file use PropertiesConfiguration or XmlConfiguration.
032 *
033 * This class extends normal Java properties by adding the possibility
034 * to use the same key many times concatenating the value strings
035 * instead of overwriting them.
036 *
037 * @author <a href="mailto:stefano@apache.org">Stefano Mazzocchi</a>
038 * @author <a href="mailto:jon@latchkey.com">Jon S. Stevens</a>
039 * @author <a href="mailto:daveb@miceda-data">Dave Bryson</a>
040 * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
041 * @author <a href="mailto:leon@opticode.co.za">Leon Messerschmidt</a>
042 * @author <a href="mailto:kjohnson@transparent.com">Kent Johnson</a>
043 * @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
044 * @author <a href="mailto:ipriha@surfeu.fi">Ilkka Priha</a>
045 * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
046 * @author <a href="mailto:mpoeschl@marmot.at">Martin Poeschl</a>
047 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
048 * @author <a href="mailto:ksh@scand.com">Konstantin Shaposhnikov</a>
049 * @author Oliver Heger
050 * @version $Id: BaseConfiguration.java 806862 2009-08-22 15:13:31Z oheger $
051 */
052 public class BaseConfiguration extends AbstractConfiguration implements Cloneable
053 {
054 /** stores the configuration key-value pairs */
055 private Map store = new LinkedMap();
056
057 /**
058 * Adds a key/value pair to the map. This routine does no magic morphing.
059 * It ensures the keylist is maintained
060 *
061 * @param key key to use for mapping
062 * @param value object to store
063 */
064 protected void addPropertyDirect(String key, Object value)
065 {
066 Object previousValue = getProperty(key);
067
068 if (previousValue == null)
069 {
070 store.put(key, value);
071 }
072 else if (previousValue instanceof List)
073 {
074 // the value is added to the existing list
075 ((List) previousValue).add(value);
076 }
077 else
078 {
079 // the previous value is replaced by a list containing the previous value and the new value
080 List list = new ArrayList();
081 list.add(previousValue);
082 list.add(value);
083
084 store.put(key, list);
085 }
086 }
087
088 /**
089 * Read property from underlying map.
090 *
091 * @param key key to use for mapping
092 *
093 * @return object associated with the given configuration key.
094 */
095 public Object getProperty(String key)
096 {
097 return store.get(key);
098 }
099
100 /**
101 * Check if the configuration is empty
102 *
103 * @return <code>true</code> if Configuration is empty,
104 * <code>false</code> otherwise.
105 */
106 public boolean isEmpty()
107 {
108 return store.isEmpty();
109 }
110
111 /**
112 * check if the configuration contains the key
113 *
114 * @param key the configuration key
115 *
116 * @return <code>true</code> if Configuration contain given key,
117 * <code>false</code> otherwise.
118 */
119 public boolean containsKey(String key)
120 {
121 return store.containsKey(key);
122 }
123
124 /**
125 * Clear a property in the configuration.
126 *
127 * @param key the key to remove along with corresponding value.
128 */
129 protected void clearPropertyDirect(String key)
130 {
131 if (containsKey(key))
132 {
133 store.remove(key);
134 }
135 }
136
137 public void clear()
138 {
139 fireEvent(EVENT_CLEAR, null, null, true);
140 store.clear();
141 fireEvent(EVENT_CLEAR, null, null, false);
142 }
143
144 /**
145 * Get the list of the keys contained in the configuration
146 * repository.
147 *
148 * @return An Iterator.
149 */
150 public Iterator getKeys()
151 {
152 return store.keySet().iterator();
153 }
154
155 /**
156 * Creates a copy of this object. This implementation will create a deep
157 * clone, i.e. the map that stores the properties is cloned, too. So changes
158 * performed at the copy won't affect the original and vice versa.
159 *
160 * @return the copy
161 * @since 1.3
162 */
163 public Object clone()
164 {
165 try
166 {
167 BaseConfiguration copy = (BaseConfiguration) super.clone();
168 copy.store = (Map) ConfigurationUtils.clone(store);
169
170 // Handle collections in the map; they have to be cloned, too
171 for (Iterator it = store.entrySet().iterator(); it.hasNext();)
172 {
173 Map.Entry e = (Map.Entry) it.next();
174 if (e.getValue() instanceof Collection)
175 {
176 copy.store.put(e.getKey(), new ArrayList((Collection) e
177 .getValue()));
178 }
179 }
180
181 return copy;
182 }
183 catch (CloneNotSupportedException cex)
184 {
185 // should not happen
186 throw new ConfigurationRuntimeException(cex);
187 }
188 }
189 }