[CODEC-174] Small (2.3%) but consistent performance gain with this patch from https://issues.apache.org/jira/secure/attachment/12612838/CODEC-174-delete-subsequence-cache-and-use-String.patch. The nicer aspect of the patch is that it simplifies the code.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/codec/trunk@1541231 13f79535-47bb-0310-9956-ffa450edef68

Author: garydgregory

src/main/java/org/apache/commons/codec/language/bm/PhoneticEngine.java

@@ -244,42 +244,6 @@ public boolean isFound() {
                                                           "des", "di", "do", "dos", "du", "van", "von"))));
     }
 
-    /**
-     * This is a performance hack to avoid overhead associated with very frequent CharSequence.subSequence calls.
-     *
-     * @param cached the character sequence to cache
-     * @return a <code>CharSequence</code> that internally caches subSequence values
-     */
-    private static CharSequence cacheSubSequence(final CharSequence cached) {
-        // return 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;
-            }
-        };
-    }
-
     /**
      * Joins some strings with an internal separator.
      * @param strings   Strings to join
@@ -370,7 +334,7 @@ private PhonemeBuilder applyFinalRules(final PhonemeBuilder phonemeBuilder, fina
 
         for (final Rule.Phoneme phoneme : phonemeBuilder.getPhonemes()) {
             PhonemeBuilder subBuilder = PhonemeBuilder.empty(phoneme.getLanguages());
-            final CharSequence phonemeText = cacheSubSequence(phoneme.getPhonemeText());
+            final String phonemeText = phoneme.getPhonemeText().toString();
 
             for (int i = 0; i < phonemeText.length();) {
                 final RulesApplication rulesApplication =
@@ -484,10 +448,9 @@ public String encode(String input, final Languages.LanguageSet languageSet) {
         PhonemeBuilder phonemeBuilder = PhonemeBuilder.empty(languageSet);
 
         // loop over each char in the input - we will handle the increment manually
-        final CharSequence inputCache = cacheSubSequence(input);
-        for (int i = 0; i < inputCache.length();) {
+        for (int i = 0; i < input.length();) {
             final RulesApplication rulesApplication =
-                    new RulesApplication(rules, inputCache, phonemeBuilder, i, maxPhonemes).invoke();
+                    new RulesApplication(rules, input, phonemeBuilder, i, maxPhonemes).invoke();
             i = rulesApplication.getI();
             phonemeBuilder = rulesApplication.getPhonemeBuilder();
         }