Author: bayard Date: Tue Jun 30 05:47:39 2009 New Revision: 789567 URL: http://svn.apache.org/viewvc?rev=789567&view=rev Log: Performance improvement. Switching from looping through a doubled array to using a Map. This probably costs more for simple cases like Java/EcmaScript/Xml, but makes up for it in the Html case. This gets performance of the testUnescapeHexCharsHtml method back down to near the same region as the original code
Modified: commons/proper/lang/trunk/src/java/org/apache/commons/lang/text/translate/LookupTranslator.java Modified: commons/proper/lang/trunk/src/java/org/apache/commons/lang/text/translate/LookupTranslator.java URL: http://svn.apache.org/viewvc/commons/proper/lang/trunk/src/java/org/apache/commons/lang/text/translate/LookupTranslator.java?rev=789567&r1=789566&r2=789567&view=diff ============================================================================== --- commons/proper/lang/trunk/src/java/org/apache/commons/lang/text/translate/LookupTranslator.java (original) +++ commons/proper/lang/trunk/src/java/org/apache/commons/lang/text/translate/LookupTranslator.java Tue Jun 30 05:47:39 2009 @@ -18,14 +18,18 @@ import java.io.IOException; import java.io.Writer; +import java.util.HashMap; /** * Translates a value using a lookup table. * @since 3.0 */ +// TODO: Replace with a RegexLookup? Performance test. public class LookupTranslator extends CharSequenceTranslator { - protected CharSequence[][] lookup; + private HashMap<CharSequence, CharSequence> lookupMap; + private int shortest = Integer.MAX_VALUE; + private int longest = 0; /** * Define the lookup table to be used in translation @@ -33,18 +37,34 @@ * @param CharSequence[][] Lookup table of size [*][2] */ public LookupTranslator(CharSequence[][] lookup) { - this.lookup = lookup; + lookupMap = new HashMap<CharSequence, CharSequence>(); + for(CharSequence[] seq : lookup) { + this.lookupMap.put(seq[0], seq[1]); + int sz = seq[0].length(); + if(sz < shortest) { + shortest = sz; + } + if(sz > longest) { + longest = sz; + } + } } /** * {...@inheritdoc} */ public int translate(CharSequence input, int index, Writer out) throws IOException { - CharSequence subsequence = input.subSequence(index, input.length()); - for(CharSequence[] seq : lookup) { - if( subsequence.toString().startsWith(seq[0].toString()) ) { - out.write(seq[1].toString()); - return seq[0].length(); + int max = longest; + if(index + longest > input.length()) { + max = input.length() - index; + } + // descend so as to get a greedy algorithm + for(int i=max; i >= shortest; i--) { + CharSequence subSeq = input.subSequence(index, index + i); + CharSequence result = lookupMap.get(subSeq); + if(result != null) { + out.write(result.toString()); + return i; } } return 0;