LANG-935: Possible performance improvement on string escape functions. Thanks to Fabian Lange and Thomas Neidhart.
git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@1668348 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index 4234a77..17ef89b 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -22,6 +22,7 @@
<body>
<release version="3.4" date="tba" description="tba">
+ <action issue="LANG-935" type="update" dev="britter" due-to="Fabian Lange, Thomas Neidhart">Possible performance improvement on string escape functions</action>
<action issue="LANG-948" type="fix" dev="britter" due-to="Andrey Khobnya">Exception while using ExtendedMessageFormat and escaping braces</action>
<action issue="LANG-1098" type="update" dev="britter" due-to="Mikhail Mazurskiy, Fabian Lange">Avoid String allocation in StrBuilder.append(CharSequence)</action>
<action issue="LANG-1098" type="update" dev="britter" due-to="Michał Kordas">Update maven-checkstyle-plugin to 2.14</action>
diff --git a/src/main/java/org/apache/commons/lang3/text/translate/LookupTranslator.java b/src/main/java/org/apache/commons/lang3/text/translate/LookupTranslator.java
index 9cf45f8..e04b722 100644
--- a/src/main/java/org/apache/commons/lang3/text/translate/LookupTranslator.java
+++ b/src/main/java/org/apache/commons/lang3/text/translate/LookupTranslator.java
@@ -19,6 +19,7 @@
import java.io.IOException;
import java.io.Writer;
import java.util.HashMap;
+import java.util.HashSet;
/**
* Translates a value using a lookup table.
@@ -29,6 +30,7 @@
public class LookupTranslator extends CharSequenceTranslator {
private final HashMap<String, CharSequence> lookupMap;
+ private final HashSet<Character> prefixSet;
private final int shortest;
private final int longest;
@@ -44,11 +46,13 @@
*/
public LookupTranslator(final CharSequence[]... lookup) {
lookupMap = new HashMap<String, CharSequence>();
+ prefixSet = new HashSet<Character>();
int _shortest = Integer.MAX_VALUE;
int _longest = 0;
if (lookup != null) {
for (final CharSequence[] seq : lookup) {
this.lookupMap.put(seq[0].toString(), seq[1]);
+ this.prefixSet.add(seq[0].charAt(0));
final int sz = seq[0].length();
if (sz < _shortest) {
_shortest = sz;
@@ -71,10 +75,17 @@
if (index + longest > input.length()) {
max = input.length() - index;
}
+
+ if (!prefixSet.contains(input.charAt(index))) {
+ // no translation exists for the input at position index
+ return 0;
+ }
+
// descend so as to get a greedy algorithm
for (int i = max; i >= shortest; i--) {
final CharSequence subSeq = input.subSequence(index, index + i);
final CharSequence result = lookupMap.get(subSeq.toString());
+
if (result != null) {
out.write(result.toString());
return i;
