1 package org.apache.lucene.search.vectorhighlight;
4 * Licensed to the Apache Software Foundation (ASF) under one or more
5 * contributor license agreements. See the NOTICE file distributed with
6 * this work for additional information regarding copyright ownership.
7 * The ASF licenses this file to You under the Apache License, Version 2.0
8 * (the "License"); you may not use this file except in compliance with
9 * the License. You may obtain a copy of the License at
11 * http://www.apache.org/licenses/LICENSE-2.0
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
20 import java.io.IOException;
21 import java.util.ArrayList;
22 import java.util.List;
24 import org.apache.lucene.document.Document;
25 import org.apache.lucene.document.Field;
26 import org.apache.lucene.document.MapFieldSelector;
27 import org.apache.lucene.index.IndexReader;
28 import org.apache.lucene.search.highlight.DefaultEncoder;
29 import org.apache.lucene.search.highlight.Encoder;
30 import org.apache.lucene.search.vectorhighlight.FieldFragList.WeightedFragInfo;
31 import org.apache.lucene.search.vectorhighlight.FieldFragList.WeightedFragInfo.SubInfo;
32 import org.apache.lucene.search.vectorhighlight.FieldPhraseList.WeightedPhraseInfo.Toffs;
34 public abstract class BaseFragmentsBuilder implements FragmentsBuilder {
36 protected String[] preTags, postTags;
37 public static final String[] COLORED_PRE_TAGS = {
38 "<b style=\"background:yellow\">", "<b style=\"background:lawngreen\">", "<b style=\"background:aquamarine\">",
39 "<b style=\"background:magenta\">", "<b style=\"background:palegreen\">", "<b style=\"background:coral\">",
40 "<b style=\"background:wheat\">", "<b style=\"background:khaki\">", "<b style=\"background:lime\">",
41 "<b style=\"background:deepskyblue\">", "<b style=\"background:deeppink\">", "<b style=\"background:salmon\">",
42 "<b style=\"background:peachpuff\">", "<b style=\"background:violet\">", "<b style=\"background:mediumpurple\">",
43 "<b style=\"background:palegoldenrod\">", "<b style=\"background:darkkhaki\">", "<b style=\"background:springgreen\">",
44 "<b style=\"background:turquoise\">", "<b style=\"background:powderblue\">"
46 public static final String[] COLORED_POST_TAGS = { "</b>" };
47 private char multiValuedSeparator = ' ';
48 private final BoundaryScanner boundaryScanner;
50 protected BaseFragmentsBuilder(){
51 this( new String[]{ "<b>" }, new String[]{ "</b>" } );
54 protected BaseFragmentsBuilder( String[] preTags, String[] postTags ){
55 this(preTags, postTags, new SimpleBoundaryScanner());
58 protected BaseFragmentsBuilder(BoundaryScanner boundaryScanner){
59 this( new String[]{ "<b>" }, new String[]{ "</b>" }, boundaryScanner );
62 protected BaseFragmentsBuilder( String[] preTags, String[] postTags, BoundaryScanner boundaryScanner ){
63 this.preTags = preTags;
64 this.postTags = postTags;
65 this.boundaryScanner = boundaryScanner;
68 static Object checkTagsArgument( Object tags ){
69 if( tags instanceof String ) return tags;
70 else if( tags instanceof String[] ) return tags;
71 throw new IllegalArgumentException( "type of preTags/postTags must be a String or String[]" );
74 public abstract List<WeightedFragInfo> getWeightedFragInfoList( List<WeightedFragInfo> src );
76 private static final Encoder NULL_ENCODER = new DefaultEncoder();
78 public String createFragment( IndexReader reader, int docId,
79 String fieldName, FieldFragList fieldFragList ) throws IOException {
80 return createFragment( reader, docId, fieldName, fieldFragList,
81 preTags, postTags, NULL_ENCODER );
84 public String[] createFragments( IndexReader reader, int docId,
85 String fieldName, FieldFragList fieldFragList, int maxNumFragments )
87 return createFragments( reader, docId, fieldName, fieldFragList, maxNumFragments,
88 preTags, postTags, NULL_ENCODER );
91 public String createFragment( IndexReader reader, int docId,
92 String fieldName, FieldFragList fieldFragList, String[] preTags, String[] postTags,
93 Encoder encoder ) throws IOException {
94 String[] fragments = createFragments( reader, docId, fieldName, fieldFragList, 1,
95 preTags, postTags, encoder );
96 if( fragments == null || fragments.length == 0 ) return null;
100 public String[] createFragments( IndexReader reader, int docId,
101 String fieldName, FieldFragList fieldFragList, int maxNumFragments,
102 String[] preTags, String[] postTags, Encoder encoder ) throws IOException {
103 if( maxNumFragments < 0 )
104 throw new IllegalArgumentException( "maxNumFragments(" + maxNumFragments + ") must be positive number." );
106 List<WeightedFragInfo> fragInfos = getWeightedFragInfoList( fieldFragList.getFragInfos() );
108 List<String> fragments = new ArrayList<String>( maxNumFragments );
109 Field[] values = getFields( reader, docId, fieldName );
110 if( values.length == 0 ) return null;
111 StringBuilder buffer = new StringBuilder();
112 int[] nextValueIndex = { 0 };
113 for( int n = 0; n < maxNumFragments && n < fragInfos.size(); n++ ){
114 WeightedFragInfo fragInfo = fragInfos.get( n );
115 fragments.add( makeFragment( buffer, nextValueIndex, values, fragInfo, preTags, postTags, encoder ) );
117 return fragments.toArray( new String[fragments.size()] );
121 protected String[] getFieldValues( IndexReader reader, int docId, String fieldName) throws IOException {
122 Document doc = reader.document( docId, new MapFieldSelector( new String[]{ fieldName } ) );
123 return doc.getValues( fieldName ); // according to Document class javadoc, this never returns null
126 protected Field[] getFields( IndexReader reader, int docId, String fieldName) throws IOException {
127 // according to javadoc, doc.getFields(fieldName) cannot be used with lazy loaded field???
128 Document doc = reader.document( docId, new MapFieldSelector( new String[]{ fieldName } ) );
129 return doc.getFields( fieldName ); // according to Document class javadoc, this never returns null
133 protected String makeFragment( StringBuilder buffer, int[] index, String[] values, WeightedFragInfo fragInfo ){
134 final int s = fragInfo.startOffset;
135 return makeFragment( fragInfo, getFragmentSource( buffer, index, values, s, fragInfo.endOffset ), s,
136 preTags, postTags, NULL_ENCODER );
139 private String makeFragment( WeightedFragInfo fragInfo, String src, int s,
140 String[] preTags, String[] postTags, Encoder encoder ){
141 StringBuilder fragment = new StringBuilder();
143 for( SubInfo subInfo : fragInfo.subInfos ){
144 for( Toffs to : subInfo.termsOffsets ){
146 .append( encoder.encodeText( src.substring( srcIndex, to.startOffset - s ) ) )
147 .append( getPreTag( preTags, subInfo.seqnum ) )
148 .append( encoder.encodeText( src.substring( to.startOffset - s, to.endOffset - s ) ) )
149 .append( getPostTag( postTags, subInfo.seqnum ) );
150 srcIndex = to.endOffset - s;
153 fragment.append( encoder.encodeText( src.substring( srcIndex ) ) );
154 return fragment.toString();
157 protected String makeFragment( StringBuilder buffer, int[] index, Field[] values, WeightedFragInfo fragInfo,
158 String[] preTags, String[] postTags, Encoder encoder ){
159 StringBuilder fragment = new StringBuilder();
160 final int s = fragInfo.getStartOffset();
161 int[] modifiedStartOffset = { s };
162 String src = getFragmentSourceMSO( buffer, index, values, s, fragInfo.getEndOffset(), modifiedStartOffset );
164 for( SubInfo subInfo : fragInfo.getSubInfos() ){
165 for( Toffs to : subInfo.getTermsOffsets() ){
167 .append( encoder.encodeText( src.substring( srcIndex, to.getStartOffset() - modifiedStartOffset[0] ) ) )
168 .append( getPreTag( preTags, subInfo.getSeqnum() ) )
169 .append( encoder.encodeText( src.substring( to.getStartOffset() - modifiedStartOffset[0], to.getEndOffset() - modifiedStartOffset[0] ) ) )
170 .append( getPostTag( postTags, subInfo.getSeqnum() ) );
171 srcIndex = to.getEndOffset() - modifiedStartOffset[0];
174 fragment.append( encoder.encodeText( src.substring( srcIndex ) ) );
175 return fragment.toString();
178 protected String getFragmentSourceMSO( StringBuilder buffer, int[] index, Field[] values,
179 int startOffset, int endOffset, int[] modifiedStartOffset ){
180 while( buffer.length() < endOffset && index[0] < values.length ){
181 buffer.append( values[index[0]].stringValue() );
182 if( values[index[0]].isTokenized() )
183 buffer.append( getMultiValuedSeparator() );
186 int eo = buffer.length() < endOffset ? buffer.length() : boundaryScanner.findEndOffset( buffer, endOffset );
187 modifiedStartOffset[0] = boundaryScanner.findStartOffset( buffer, startOffset );
188 return buffer.substring( modifiedStartOffset[0], eo );
192 protected String getFragmentSource( StringBuilder buffer, int[] index, String[] values,
193 int startOffset, int endOffset ){
194 while( buffer.length() < endOffset && index[0] < values.length ){
195 buffer.append( values[index[0]] );
196 buffer.append( multiValuedSeparator );
199 int eo = buffer.length() < endOffset ? buffer.length() : endOffset;
200 return buffer.substring( startOffset, eo );
203 protected String getFragmentSource( StringBuilder buffer, int[] index, Field[] values,
204 int startOffset, int endOffset ){
205 while( buffer.length() < endOffset && index[0] < values.length ){
206 buffer.append( values[index[0]].stringValue() );
207 if( values[index[0]].isTokenized() )
208 buffer.append( multiValuedSeparator );
211 int eo = buffer.length() < endOffset ? buffer.length() : endOffset;
212 return buffer.substring( startOffset, eo );
215 public void setMultiValuedSeparator( char separator ){
216 multiValuedSeparator = separator;
219 public char getMultiValuedSeparator(){
220 return multiValuedSeparator;
223 protected String getPreTag( int num ){
224 return getPreTag( preTags, num );
227 protected String getPostTag( int num ){
228 return getPostTag( postTags, num );
231 protected String getPreTag( String[] preTags, int num ){
232 int n = num % preTags.length;
236 protected String getPostTag( String[] postTags, int num ){
237 int n = num % postTags.length;