From 1631ebfe5c0fd0927c3f6ea8ca2f5e1671bfcf53 Mon Sep 17 00:00:00 2001
From: Koji Sekiguchi <koji@apache.org>
Date: Sun, 16 Oct 2011 03:45:34 +0000
Subject: [PATCH] LUCENE-3513: Add SimpleFragListBuilder constructor with
 margin parameter

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1184753 13f79535-47bb-0310-9956-ffa450edef68
---
 lucene/contrib/CHANGES.txt                    |  3 +++
 .../SimpleFragListBuilder.java                | 27 ++++++++++++++-----
 .../SimpleFragListBuilderTest.java            |  6 ++---
 3 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/lucene/contrib/CHANGES.txt b/lucene/contrib/CHANGES.txt
index 5608c1c2ead..12ea75c612e 100644
--- a/lucene/contrib/CHANGES.txt
+++ b/lucene/contrib/CHANGES.txt
@@ -130,6 +130,9 @@ API Changes
  * LUCENE-3436: Add SuggestMode to the spellchecker, so you can specify the strategy
    for suggesting related terms.  (James Dyer via Robert Muir)
 
+ * LUCENE-3513: Add SimpleFragListBuilder constructor with margin parameter.
+   (Kelsey Francis via Koji Sekiguchi)
+
 ======================= Lucene 3.4.0 ================
 
 New Features
diff --git a/lucene/contrib/highlighter/src/java/org/apache/lucene/search/vectorhighlight/SimpleFragListBuilder.java b/lucene/contrib/highlighter/src/java/org/apache/lucene/search/vectorhighlight/SimpleFragListBuilder.java
index 2c318d510c2..8a9447bc841 100644
--- a/lucene/contrib/highlighter/src/java/org/apache/lucene/search/vectorhighlight/SimpleFragListBuilder.java
+++ b/lucene/contrib/highlighter/src/java/org/apache/lucene/search/vectorhighlight/SimpleFragListBuilder.java
@@ -28,13 +28,28 @@ import org.apache.lucene.search.vectorhighlight.FieldPhraseList.WeightedPhraseIn
  */
 public class SimpleFragListBuilder implements FragListBuilder {
   
-  public static final int MARGIN = 6;
-  public static final int MIN_FRAG_CHAR_SIZE = MARGIN * 3;
+  public static final int MARGIN_DEFAULT = 6;
+  public static final int MIN_FRAG_CHAR_SIZE_FACTOR = 3;
+
+  final int margin;
+  final int minFragCharSize;
+
+  public SimpleFragListBuilder( int margin ){
+    if( margin < 0 )
+      throw new IllegalArgumentException( "margin(" + margin + ") is too small. It must be 0 or higher." );
+
+    this.margin = margin;
+    this.minFragCharSize = Math.max( 1, margin * MIN_FRAG_CHAR_SIZE_FACTOR );
+  }
+
+  public SimpleFragListBuilder(){
+    this( MARGIN_DEFAULT );
+  }
 
   public FieldFragList createFieldFragList(FieldPhraseList fieldPhraseList, int fragCharSize) {
-    if( fragCharSize < MIN_FRAG_CHAR_SIZE )
+    if( fragCharSize < minFragCharSize )
       throw new IllegalArgumentException( "fragCharSize(" + fragCharSize + ") is too small. It must be " +
-          MIN_FRAG_CHAR_SIZE + " or higher." );
+          minFragCharSize + " or higher." );
 
     FieldFragList ffl = new FieldFragList( fragCharSize );
 
@@ -56,8 +71,8 @@ public class SimpleFragListBuilder implements FragListBuilder {
 
       wpil.clear();
       wpil.add( phraseInfo );
-      int st = phraseInfo.getStartOffset() - MARGIN < startOffset ?
-          startOffset : phraseInfo.getStartOffset() - MARGIN;
+      int st = phraseInfo.getStartOffset() - margin < startOffset ?
+          startOffset : phraseInfo.getStartOffset() - margin;
       int en = st + fragCharSize;
       if( phraseInfo.getEndOffset() > en )
         en = phraseInfo.getEndOffset();
diff --git a/lucene/contrib/highlighter/src/test/org/apache/lucene/search/vectorhighlight/SimpleFragListBuilderTest.java b/lucene/contrib/highlighter/src/test/org/apache/lucene/search/vectorhighlight/SimpleFragListBuilderTest.java
index 20d0949a0e9..5f30c6186e4 100644
--- a/lucene/contrib/highlighter/src/test/org/apache/lucene/search/vectorhighlight/SimpleFragListBuilderTest.java
+++ b/lucene/contrib/highlighter/src/test/org/apache/lucene/search/vectorhighlight/SimpleFragListBuilderTest.java
@@ -31,7 +31,7 @@ public class SimpleFragListBuilderTest extends AbstractTestCase {
   public void testTooSmallFragSize() throws Exception {
     try{
       SimpleFragListBuilder sflb = new SimpleFragListBuilder();
-      sflb.createFieldFragList( fpl(new TermQuery(new Term(F, "a")), "b c d" ), SimpleFragListBuilder.MIN_FRAG_CHAR_SIZE - 1 );
+      sflb.createFieldFragList( fpl(new TermQuery(new Term(F, "a")), "b c d" ), sflb.minFragCharSize - 1 );
       fail( "IllegalArgumentException must be thrown" );
     }
     catch ( IllegalArgumentException expected ) {
@@ -40,7 +40,7 @@ public class SimpleFragListBuilderTest extends AbstractTestCase {
   
   public void testSmallerFragSizeThanTermQuery() throws Exception {
     SimpleFragListBuilder sflb = new SimpleFragListBuilder();
-    FieldFragList ffl = sflb.createFieldFragList( fpl(new TermQuery(new Term(F, "abcdefghijklmnopqrs")), "abcdefghijklmnopqrs" ), SimpleFragListBuilder.MIN_FRAG_CHAR_SIZE );
+    FieldFragList ffl = sflb.createFieldFragList( fpl(new TermQuery(new Term(F, "abcdefghijklmnopqrs")), "abcdefghijklmnopqrs" ), sflb.minFragCharSize );
     assertEquals( 1, ffl.getFragInfos().size() );
     assertEquals( "subInfos=(abcdefghijklmnopqrs((0,19)))/1.0(0,19)", ffl.getFragInfos().get( 0 ).toString() );
   }
@@ -52,7 +52,7 @@ public class SimpleFragListBuilderTest extends AbstractTestCase {
     phraseQuery.add(new Term(F, "abcdefgh"));
     phraseQuery.add(new Term(F, "jklmnopqrs"));
 
-    FieldFragList ffl = sflb.createFieldFragList( fpl(phraseQuery, "abcdefgh   jklmnopqrs" ), SimpleFragListBuilder.MIN_FRAG_CHAR_SIZE );
+    FieldFragList ffl = sflb.createFieldFragList( fpl(phraseQuery, "abcdefgh   jklmnopqrs" ), sflb.minFragCharSize );
     assertEquals( 1, ffl.getFragInfos().size() );
     if (VERBOSE) System.out.println( ffl.getFragInfos().get( 0 ).toString() );
     assertEquals( "subInfos=(abcdefghjklmnopqrs((0,21)))/1.0(0,21)", ffl.getFragInfos().get( 0 ).toString() );