SOLR-521: StopFilterFactory support for enablePositionIncrements

git-svn-id: https://svn.apache.org/repos/asf/lucene/solr/trunk@648433 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -247,6 +247,9 @@ New Features
     BinaryResponseParser for utilizing the binary format via SolrJ.
     (Noble Paul, yonik)
 
+45. SOLR-521: StopFilterFactory support for "enablePositionIncrements"
+    (Walter Ferrara via hossman)
+    
 Changes in runtime behavior
 
 Optimizations

example/solr/conf/schema.xml

@@ -164,7 +164,15 @@
         <!-- in this example, we will only use synonyms at query time
         <filter class="solr.SynonymFilterFactory" synonyms="index_synonyms.txt" ignoreCase="true" expand="false"/>
         -->
-        <filter class="solr.StopFilterFactory" ignoreCase="true" words="stopwords.txt"/>
+        <!-- Case insensitive stop word removal.
+             enablePositionIncrements=true ensures that a 'gap' is left to
+             allow for accurate phrase queries.
+        -->
+        <filter class="solr.StopFilterFactory"
+                ignoreCase="true"
+                words="stopwords.txt"
+                enablePositionIncrements="true"
+                />
         <filter class="solr.WordDelimiterFilterFactory" generateWordParts="1" generateNumberParts="1" catenateWords="1" catenateNumbers="1" catenateAll="0" splitOnCaseChange="1"/>
         <filter class="solr.LowerCaseFilterFactory"/>
         <filter class="solr.EnglishPorterFilterFactory" protected="protwords.txt"/>

src/java/org/apache/solr/analysis/StopFilterFactory.java

@@ -35,6 +35,7 @@ public class StopFilterFactory extends BaseTokenFilterFactory implements Resourc
   public void inform(ResourceLoader loader) {
     String stopWordFile = args.get("words");
     ignoreCase = getBoolean("ignoreCase",false);
+    enablePositionIncrements = getBoolean("enablePositionIncrements",false);
 
     if (stopWordFile != null) {
       try {
@@ -50,8 +51,11 @@ public class StopFilterFactory extends BaseTokenFilterFactory implements Resourc
 
   private Set stopWords;
   private boolean ignoreCase;
+  private boolean enablePositionIncrements;
 
   public StopFilter create(TokenStream input) {
-    return new StopFilter(input,stopWords,ignoreCase);
+    StopFilter stopFilter = new StopFilter(input,stopWords,ignoreCase);
+    stopFilter.setEnablePositionIncrements(enablePositionIncrements);
+    return stopFilter;
   }
 }