Add a performance test.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/codec/trunk@1541177 13f79535-47bb-0310-9956-ffa450edef68

Author: garydgregory

src/test/java/org/apache/commons/codec/language/bm/CacheSubSequencePerformanceTest.java

@@ -0,0 +1,80 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.codec.language.bm;
+
+import org.junit.Test;
+
+public class CacheSubSequencePerformanceTest {
+
+    @Test
+    public void test() {
+        final int times = 10000000;
+        System.out.print("Test with String : ");
+        test("Angelo", times);
+        System.out.print("Test with StringBuilder : ");
+        test(new StringBuilder("Angelo"), times);
+        System.out.print("Test with cached String : ");
+        test(cacheSubSequence("Angelo"), times);
+        System.out.print("Test with cached StringBuilder : ");
+        test(cacheSubSequence(new StringBuilder("Angelo")), times);
+    }
+
+    private void test(final CharSequence input, final int times) {
+        final long beginTime = System.currentTimeMillis();
+        for (int i = 0; i < times; i++) {
+            test(input);
+        }
+        System.out.println(System.currentTimeMillis() - beginTime + " millis");
+    }
+
+    private void test(final CharSequence input) {
+        for (int i = 0; i < input.length(); i++) {
+            for (int j = i; j <= input.length(); j++) {
+                input.subSequence(i, j);
+            }
+        }
+    }
+
+    private CharSequence cacheSubSequence(final CharSequence cached) {
+        final CharSequence[][] cache = new CharSequence[cached.length()][cached.length()];
+        return new CharSequence() {
+            @Override
+            public char charAt(final int index) {
+                return cached.charAt(index);
+            }
+
+            @Override
+            public int length() {
+                return cached.length();
+            }
+
+            @Override
+            public CharSequence subSequence(final int start, final int end) {
+                if (start == end) {
+                    return "";
+                }
+                CharSequence res = cache[start][end - 1];
+                if (res == null) {
+                    res = cached.subSequence(start, end);
+                    cache[start][end - 1] = res;
+                }
+                return res;
+            }
+        };
+    }
+}