Index: contrib/CHANGES.txt
===================================================================
--- contrib/CHANGES.txt	(revision 982424)
+++ contrib/CHANGES.txt	(working copy)
@@ -43,6 +43,9 @@
  * LUCENE-2323: Moved contrib/wikipedia functionality into contrib/analyzers.
    Additionally the package was changed from org.apache.lucene.wikipedia.analysis
    to org.apache.lucene.analysis.wikipedia.  (Robert Muir)
+
+ * LUCENE-2581: Added methods to FragmentsBuilder interface. These methods
+   are used to set pre/post tags and Encoder. (Koji Sekiguchi)
     
 Changes in runtime behavior
 
@@ -190,6 +193,9 @@
  * LUCENE-2503: Added lighter stemming alternatives for European languages. 
    (Robert Muir)
 
+ * LUCENE-2581: FastVectorHighlighter: add Encoder to FragmentsBuilder.
+   (Koji Sekiguchi)
+
 Build
 
  * LUCENE-2124: Moved the JDK-based collation support from contrib/collation 
Index: contrib/highlighter/src/test/org/apache/lucene/search/vectorhighlight/SimpleFragmentsBuilderTest.java
===================================================================
--- contrib/highlighter/src/test/org/apache/lucene/search/vectorhighlight/SimpleFragmentsBuilderTest.java	(revision 982424)
+++ contrib/highlighter/src/test/org/apache/lucene/search/vectorhighlight/SimpleFragmentsBuilderTest.java	(working copy)
@@ -27,6 +27,7 @@
 import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.IndexWriterConfig.OpenMode;
 import org.apache.lucene.search.Query;
+import org.apache.lucene.search.highlight.SimpleHTMLEncoder;
 
 public class SimpleFragmentsBuilderTest extends AbstractTestCase {
   
@@ -59,6 +60,15 @@
     assertEquals( "b b <b>a</b> b <b>a</b> b b b b b ", f[1] );
     assertEquals( "<b>c</b> <b>a</b> <b>a</b> b b", f[2] );
   }
+  
+  public void testTagsAndEncoder() throws Exception {
+    FieldFragList ffl = ffl( "a", "<h1> a </h1>" );
+    SimpleFragmentsBuilder sfb = new SimpleFragmentsBuilder();
+    String[] preTags = { "[" };
+    String[] postTags = { "]" };
+    assertEquals( "&lt;h1&gt; [a] &lt;/h1&gt;",
+        sfb.createFragment( reader, 0, F, ffl, preTags, postTags, new SimpleHTMLEncoder() ) );
+  }
 
   private FieldFragList ffl( String queryValue, String indexValue ) throws Exception {
     make1d1fIndex( indexValue );
Index: contrib/highlighter/src/java/org/apache/lucene/search/vectorhighlight/FastVectorHighlighter.java
===================================================================
--- contrib/highlighter/src/java/org/apache/lucene/search/vectorhighlight/FastVectorHighlighter.java	(revision 982424)
+++ contrib/highlighter/src/java/org/apache/lucene/search/vectorhighlight/FastVectorHighlighter.java	(working copy)
@@ -21,6 +21,7 @@
 
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.search.Query;
+import org.apache.lucene.search.highlight.Encoder;
 
 /**
  * Another highlighter implementation.
@@ -43,7 +44,7 @@
   }
 
   /**
-   * a constructor. Using SimpleFragListBuilder and ScoreOrderFragmentsBuilder.
+   * a constructor. Using {@link SimpleFragListBuilder} and {@link ScoreOrderFragmentsBuilder}.
    * 
    * @param phraseHighlight true or false for phrase highlighting
    * @param fieldMatch true of false for field matching
@@ -53,12 +54,12 @@
   }
 
   /**
-   * a constructor. A FragListBuilder and a FragmentsBuilder can be specified (plugins).
+   * a constructor. A {@link FragListBuilder} and a {@link FragmentsBuilder} can be specified (plugins).
    * 
    * @param phraseHighlight true of false for phrase highlighting
    * @param fieldMatch true of false for field matching
-   * @param fragListBuilder an instance of FragListBuilder
-   * @param fragmentsBuilder an instance of FragmentsBuilder
+   * @param fragListBuilder an instance of {@link FragListBuilder}
+   * @param fragmentsBuilder an instance of {@link FragmentsBuilder}
    */
   public FastVectorHighlighter( boolean phraseHighlight, boolean fieldMatch,
       FragListBuilder fragListBuilder, FragmentsBuilder fragmentsBuilder ){
@@ -69,10 +70,10 @@
   }
 
   /**
-   * create a FieldQuery object.
+   * create a {@link FieldQuery} object.
    * 
    * @param query a query
-   * @return the created FieldQuery object
+   * @return the created {@link FieldQuery} object
    */
   public FieldQuery getFieldQuery( Query query ){
     return new FieldQuery( query, phraseHighlight, fieldMatch );
@@ -81,8 +82,8 @@
   /**
    * return the best fragment.
    * 
-   * @param fieldQuery FieldQuery object
-   * @param reader IndexReader of the index
+   * @param fieldQuery {@link FieldQuery} object
+   * @param reader {@link IndexReader} of the index
    * @param docId document id to be highlighted
    * @param fieldName field of the document to be highlighted
    * @param fragCharSize the length (number of chars) of a fragment
@@ -98,8 +99,8 @@
   /**
    * return the best fragments.
    * 
-   * @param fieldQuery FieldQuery object
-   * @param reader IndexReader of the index
+   * @param fieldQuery {@link FieldQuery} object
+   * @param reader {@link IndexReader} of the index
    * @param docId document id to be highlighted
    * @param fieldName field of the document to be highlighted
    * @param fragCharSize the length (number of chars) of a fragment
@@ -113,6 +114,51 @@
     FieldFragList fieldFragList = getFieldFragList( fieldQuery, reader, docId, fieldName, fragCharSize );
     return fragmentsBuilder.createFragments( reader, docId, fieldName, fieldFragList, maxNumFragments );
   }
+
+  /**
+   * return the best fragment.
+   * 
+   * @param fieldQuery {@link FieldQuery} object
+   * @param reader {@link IndexReader} of the index
+   * @param docId document id to be highlighted
+   * @param fieldName field of the document to be highlighted
+   * @param fragCharSize the length (number of chars) of a fragment
+   * @param preTags pre-tags to be used to highlight terms
+   * @param postTags post-tags to be used to highlight terms
+   * @param encoder an encoder that generates encoded text
+   * @return the best fragment (snippet) string
+   * @throws IOException
+   */
+  public final String getBestFragment( final FieldQuery fieldQuery, IndexReader reader, int docId,
+      String fieldName, int fragCharSize, String[] preTags, String[] postTags,
+      Encoder encoder ) throws IOException {
+    FieldFragList fieldFragList = getFieldFragList( fieldQuery, reader, docId, fieldName, fragCharSize );
+    return fragmentsBuilder.createFragment( reader, docId, fieldName, fieldFragList, preTags, postTags, encoder );
+  }
+
+  /**
+   * return the best fragments.
+   * 
+   * @param fieldQuery {@link FieldQuery} object
+   * @param reader {@link IndexReader} of the index
+   * @param docId document id to be highlighted
+   * @param fieldName field of the document to be highlighted
+   * @param fragCharSize the length (number of chars) of a fragment
+   * @param maxNumFragments maximum number of fragments
+   * @param preTags pre-tags to be used to highlight terms
+   * @param postTags post-tags to be used to highlight terms
+   * @param encoder an encoder that generates encoded text
+   * @return created fragments or null when no fragments created.
+   *         size of the array can be less than maxNumFragments
+   * @throws IOException
+   */
+  public final String[] getBestFragments( final FieldQuery fieldQuery, IndexReader reader, int docId,
+      String fieldName, int fragCharSize, int maxNumFragments, String[] preTags, String[] postTags,
+      Encoder encoder ) throws IOException {
+    FieldFragList fieldFragList = getFieldFragList( fieldQuery, reader, docId, fieldName, fragCharSize );
+    return fragmentsBuilder.createFragments( reader, docId, fieldName, fieldFragList, maxNumFragments,
+        preTags, postTags, encoder );
+  }
   
   private FieldFragList getFieldFragList( final FieldQuery fieldQuery, IndexReader reader, int docId,
       String fieldName, int fragCharSize ) throws IOException {
Index: contrib/highlighter/src/java/org/apache/lucene/search/vectorhighlight/BaseFragmentsBuilder.java
===================================================================
--- contrib/highlighter/src/java/org/apache/lucene/search/vectorhighlight/BaseFragmentsBuilder.java	(revision 982424)
+++ contrib/highlighter/src/java/org/apache/lucene/search/vectorhighlight/BaseFragmentsBuilder.java	(working copy)
@@ -25,6 +25,8 @@
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.MapFieldSelector;
 import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.search.highlight.DefaultEncoder;
+import org.apache.lucene.search.highlight.Encoder;
 import org.apache.lucene.search.vectorhighlight.FieldFragList.WeightedFragInfo;
 import org.apache.lucene.search.vectorhighlight.FieldFragList.WeightedFragInfo.SubInfo;
 import org.apache.lucene.search.vectorhighlight.FieldPhraseList.WeightedPhraseInfo.Toffs;
@@ -59,17 +61,34 @@
   }
   
   public abstract List<WeightedFragInfo> getWeightedFragInfoList( List<WeightedFragInfo> src );
+
+  private static final Encoder NULL_ENCODER = new DefaultEncoder();
   
   public String createFragment( IndexReader reader, int docId,
       String fieldName, FieldFragList fieldFragList ) throws IOException {
-    String[] fragments = createFragments( reader, docId, fieldName, fieldFragList, 1 );
+    return createFragment( reader, docId, fieldName, fieldFragList,
+        preTags, postTags, NULL_ENCODER );
+  }
+
+  public String[] createFragments( IndexReader reader, int docId,
+      String fieldName, FieldFragList fieldFragList, int maxNumFragments )
+      throws IOException {
+    return createFragments( reader, docId, fieldName, fieldFragList, maxNumFragments,
+        preTags, postTags, NULL_ENCODER );
+  }
+  
+  public String createFragment( IndexReader reader, int docId,
+      String fieldName, FieldFragList fieldFragList, String[] preTags, String[] postTags,
+      Encoder encoder ) throws IOException {
+    String[] fragments = createFragments( reader, docId, fieldName, fieldFragList, 1,
+        preTags, postTags, encoder );
     if( fragments == null || fragments.length == 0 ) return null;
     return fragments[0];
   }
 
   public String[] createFragments( IndexReader reader, int docId,
-      String fieldName, FieldFragList fieldFragList, int maxNumFragments )
-      throws IOException {
+      String fieldName, FieldFragList fieldFragList, int maxNumFragments,
+      String[] preTags, String[] postTags, Encoder encoder ) throws IOException {
     if( maxNumFragments < 0 )
       throw new IllegalArgumentException( "maxNumFragments(" + maxNumFragments + ") must be positive number." );
 
@@ -82,7 +101,7 @@
     int[] nextValueIndex = { 0 };
     for( int n = 0; n < maxNumFragments && n < fragInfos.size(); n++ ){
       WeightedFragInfo fragInfo = fragInfos.get( n );
-      fragments.add( makeFragment( buffer, nextValueIndex, values, fragInfo ) );
+      fragments.add( makeFragment( buffer, nextValueIndex, values, fragInfo, preTags, postTags, encoder ) );
     }
     return fragments.toArray( new String[fragments.size()] );
   }
@@ -102,25 +121,32 @@
   @Deprecated
   protected String makeFragment( StringBuilder buffer, int[] index, String[] values, WeightedFragInfo fragInfo ){
     final int s = fragInfo.startOffset;
-    return makeFragment( fragInfo, getFragmentSource( buffer, index, values, s, fragInfo.endOffset ), s );
+    return makeFragment( fragInfo, getFragmentSource( buffer, index, values, s, fragInfo.endOffset ), s,
+        preTags, postTags, NULL_ENCODER );
   }
 
-  protected String makeFragment( StringBuilder buffer, int[] index, Field[] values, WeightedFragInfo fragInfo ){
+  protected String makeFragment( StringBuilder buffer, int[] index, Field[] values, WeightedFragInfo fragInfo,
+      String[] preTags, String[] postTags, Encoder encoder ){
     final int s = fragInfo.startOffset;
-    return makeFragment( fragInfo, getFragmentSource( buffer, index, values, s, fragInfo.endOffset ), s );
+    return makeFragment( fragInfo, getFragmentSource( buffer, index, values, s, fragInfo.endOffset ), s,
+        preTags, postTags, encoder );
   }
   
-  private String makeFragment( WeightedFragInfo fragInfo, String src, int s ){
+  private String makeFragment( WeightedFragInfo fragInfo, String src, int s,
+      String[] preTags, String[] postTags, Encoder encoder ){
     StringBuilder fragment = new StringBuilder();
     int srcIndex = 0;
     for( SubInfo subInfo : fragInfo.subInfos ){
       for( Toffs to : subInfo.termsOffsets ){
-        fragment.append( src.substring( srcIndex, to.startOffset - s ) ).append( getPreTag( subInfo.seqnum ) )
-          .append( src.substring( to.startOffset - s, to.endOffset - s ) ).append( getPostTag( subInfo.seqnum ) );
+        fragment
+          .append( encoder.encodeText( src.substring( srcIndex, to.startOffset - s ) ) )
+          .append( getPreTag( preTags, subInfo.seqnum ) )
+          .append( encoder.encodeText( src.substring( to.startOffset - s, to.endOffset - s ) ) )
+          .append( getPostTag( postTags, subInfo.seqnum ) );
         srcIndex = to.endOffset - s;
       }
     }
-    fragment.append( src.substring( srcIndex ) );
+    fragment.append( encoder.encodeText( src.substring( srcIndex ) ) );
     return fragment.toString();
   }
   
@@ -146,13 +172,21 @@
     int eo = buffer.length() < endOffset ? buffer.length() : endOffset;
     return buffer.substring( startOffset, eo );
   }
+
+  protected String getPreTag( int num ){
+    return getPreTag( preTags, num );
+  }
   
-  protected String getPreTag( int num ){
+  protected String getPostTag( int num ){
+    return getPostTag( postTags, num );
+  }
+  
+  protected String getPreTag( String[] preTags, int num ){
     int n = num % preTags.length;
     return preTags[n];
   }
   
-  protected String getPostTag( int num ){
+  protected String getPostTag( String[] postTags, int num ){
     int n = num % postTags.length;
     return postTags[n];
   }
Index: contrib/highlighter/src/java/org/apache/lucene/search/vectorhighlight/FragmentsBuilder.java
===================================================================
--- contrib/highlighter/src/java/org/apache/lucene/search/vectorhighlight/FragmentsBuilder.java	(revision 982424)
+++ contrib/highlighter/src/java/org/apache/lucene/search/vectorhighlight/FragmentsBuilder.java	(working copy)
@@ -20,10 +20,12 @@
 import java.io.IOException;
 
 import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.search.highlight.Encoder;
 
 /**
- * FragmentsBuilder is an interface for fragments (snippets) builder classes.
- * A FragmentsBuilder class can be plugged in to Highlighter.
+ * {@link org.apache.lucene.search.vectorhighlight.FragmentsBuilder} is an interface for fragments (snippets) builder classes.
+ * A {@link org.apache.lucene.search.vectorhighlight.FragmentsBuilder} class can be plugged in to
+ * {@link org.apache.lucene.search.vectorhighlight.FastVectorHighlighter}.
  */
 public interface FragmentsBuilder {
 
@@ -54,4 +56,40 @@
    */
   public String[] createFragments( IndexReader reader, int docId, String fieldName,
       FieldFragList fieldFragList, int maxNumFragments ) throws IOException;
+
+  /**
+   * create a fragment.
+   * 
+   * @param reader IndexReader of the index
+   * @param docId document id to be highlighted
+   * @param fieldName field of the document to be highlighted
+   * @param fieldFragList FieldFragList object
+   * @param preTags pre-tags to be used to highlight terms
+   * @param postTags post-tags to be used to highlight terms
+   * @param encoder an encoder that generates encoded text
+   * @return a created fragment or null when no fragment created
+   * @throws IOException
+   */
+  public String createFragment( IndexReader reader, int docId, String fieldName,
+      FieldFragList fieldFragList, String[] preTags, String[] postTags,
+      Encoder encoder ) throws IOException;
+
+  /**
+   * create multiple fragments.
+   * 
+   * @param reader IndexReader of the index
+   * @param docId document id to be highlighter
+   * @param fieldName field of the document to be highlighted
+   * @param fieldFragList FieldFragList object
+   * @param maxNumFragments maximum number of fragments
+   * @param preTags pre-tags to be used to highlight terms
+   * @param postTags post-tags to be used to highlight terms
+   * @param encoder an encoder that generates encoded text
+   * @return created fragments or null when no fragments created.
+   *         size of the array can be less than maxNumFragments
+   * @throws IOException
+   */
+  public String[] createFragments( IndexReader reader, int docId, String fieldName,
+      FieldFragList fieldFragList, int maxNumFragments, String[] preTags, String[] postTags,
+      Encoder encoder ) throws IOException;
 }