Analysis: expose Lucene PatternReplaceFilter.

modules/elasticsearch/src/main/java/org/apache/lucene/analysis/pattern/PatternReplaceFilter.java

@@ -0,0 +1,85 @@
+/*
+ * Licensed to Elastic Search and Shay Banon under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. Elastic Search 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.lucene.analysis.pattern;
+
+import org.apache.lucene.analysis.TokenFilter;
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
+
+import java.util.regex.Pattern;
+import java.util.regex.Matcher;
+import java.io.IOException;
+
+/**
+ * A TokenFilter which applies a Pattern to each token in the stream,
+ * replacing match occurances with the specified replacement string.
+ *
+ * <p>
+ * <b>Note:</b> Depending on the input and the pattern used and the input
+ * TokenStream, this TokenFilter may produce Tokens whose text is the empty
+ * string.
+ * </p>
+ * 
+ * @see Pattern
+ */
+public final class PatternReplaceFilter extends TokenFilter {
+  private final Pattern p;
+  private final String replacement;
+  private final boolean all;
+  private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
+  private final Matcher m;
+
+  /**
+   * Constructs an instance to replace either the first, or all occurances
+   *
+   * @param in the TokenStream to process
+   * @param p the patterm to apply to each Token
+   * @param replacement the "replacement string" to substitute, if null a
+   *        blank string will be used. Note that this is not the literal
+   *        string that will be used, '$' and '\' have special meaning.
+   * @param all if true, all matches will be replaced otherwise just the first match.
+   * @see Matcher#quoteReplacement
+   */
+  public PatternReplaceFilter(TokenStream in,
+                              Pattern p,
+                              String replacement,
+                              boolean all) {
+    super(in);
+    this.p=p;
+    this.replacement = (null == replacement) ? "" : replacement;
+    this.all=all;
+    this.m = p.matcher(termAtt);
+  }
+
+  @Override
+  public boolean incrementToken() throws IOException {
+    if (!input.incrementToken()) return false;
+    
+    m.reset();
+    if (m.find()) {
+      // replaceAll/replaceFirst will reset() this previous find.
+      String transformed = all ? m.replaceAll(replacement) : m.replaceFirst(replacement);
+      termAtt.setEmpty().append(transformed);
+    }
+
+    return true;
+  }
+
+}

modules/elasticsearch/src/main/java/org/elasticsearch/index/analysis/AnalysisModule.java

@@ -377,6 +377,7 @@ public class AnalysisModule extends AbstractModule {
             tokenFiltersBindings.processTokenFilter("synonym", SynonymTokenFilterFactory.class);
             tokenFiltersBindings.processTokenFilter("elision", ElisionTokenFilterFactory.class);
 
+            tokenFiltersBindings.processTokenFilter("pattern_replace", PatternReplaceTokenFilterFactory.class);
             tokenFiltersBindings.processTokenFilter("phonetic", PhoneticTokenFilterFactory.class);
             tokenFiltersBindings.processTokenFilter("dictionary_decompounder", DictionaryCompoundWordTokenFilterFactory.class);
             tokenFiltersBindings.processTokenFilter("hypennation_decompounder", HyphenationCompoundWordTokenFilterFactory.class);

modules/elasticsearch/src/main/java/org/elasticsearch/index/analysis/PatternReplaceTokenFilterFactory.java

@@ -0,0 +1,65 @@
+/*
+ * Licensed to Elastic Search and Shay Banon under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. Elastic Search 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.elasticsearch.index.analysis;
+
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.pattern.PatternReplaceFilter;
+import org.elasticsearch.ElasticSearchIllegalArgumentException;
+import org.elasticsearch.common.inject.Inject;
+import org.elasticsearch.common.inject.assistedinject.Assisted;
+import org.elasticsearch.common.regex.Regex;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.index.Index;
+import org.elasticsearch.index.settings.IndexSettings;
+
+import java.io.IOException;
+import java.io.Reader;
+import java.util.regex.Pattern;
+
+public class PatternReplaceTokenFilterFactory extends AbstractTokenFilterFactory {
+
+    private final Pattern pattern;
+    private final String replacement;
+    private final boolean all;
+
+    @Inject public PatternReplaceTokenFilterFactory(Index index, @IndexSettings Settings indexSettings, @Assisted String name, @Assisted Settings settings) {
+        super(index, indexSettings, name, settings);
+
+        String sPattern = settings.get("pattern", "");
+        if (sPattern == null) {
+            throw new ElasticSearchIllegalArgumentException("pattern is missing for [" + name + "] token filter of type 'pattern_replace'");
+        }
+
+        this.pattern = Regex.compile(sPattern, settings.get("flags"));
+
+        String sReplacement = settings.get("replacement", "");
+        if (sReplacement == null) {
+            throw new ElasticSearchIllegalArgumentException("replacement is missing for [" + name + "] token filter of type 'pattern_replace'");
+        }
+
+        this.replacement = sReplacement;
+
+        this.all = settings.getAsBoolean("all", true);
+    }
+
+    @Override public TokenStream create(TokenStream tokenStream) {
+        return new PatternReplaceFilter(tokenStream, pattern, replacement, all);
+    }
+}