package org.apache.lucene.search.vectorhighlight;
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.
*/
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.apache.lucene.document.Document;
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;
public abstract class BaseFragmentsBuilder implements FragmentsBuilder {
protected String[] preTags, postTags;
public static final String[] COLORED_PRE_TAGS = {
"<b style=\"background:yellow\">", "<b style=\"background:lawngreen\">", "<b style=\"background:aquamarine\">",
"<b style=\"background:magenta\">", "<b style=\"background:palegreen\">", "<b style=\"background:coral\">",
"<b style=\"background:wheat\">", "<b style=\"background:khaki\">", "<b style=\"background:lime\">",
"<b style=\"background:deepskyblue\">", "<b style=\"background:deeppink\">", "<b style=\"background:salmon\">",
"<b style=\"background:peachpuff\">", "<b style=\"background:violet\">", "<b style=\"background:mediumpurple\">",
"<b style=\"background:palegoldenrod\">", "<b style=\"background:darkkhaki\">", "<b style=\"background:springgreen\">",
"<b style=\"background:turquoise\">", "<b style=\"background:powderblue\">"
};
public static final String[] COLORED_POST_TAGS = { "</b>" };
private char multiValuedSeparator = ' ';
protected BaseFragmentsBuilder(){
this( new String[]{ "<b>" }, new String[]{ "</b>" } );
}
protected BaseFragmentsBuilder( String[] preTags, String[] postTags ){
this.preTags = preTags;
this.postTags = postTags;
}
static Object checkTagsArgument( Object tags ){
if( tags instanceof String ) return tags;
else if( tags instanceof String[] ) return tags;
throw new IllegalArgumentException( "type of preTags/postTags must be a String or String[]" );
}
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 {
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,
String[] preTags, String[] postTags, Encoder encoder ) throws IOException {
if( maxNumFragments < 0 )
throw new IllegalArgumentException( "maxNumFragments(" + maxNumFragments + ") must be positive number." );
List<WeightedFragInfo> fragInfos = getWeightedFragInfoList( fieldFragList.fragInfos );
List<String> fragments = new ArrayList<String>( maxNumFragments );
Field[] values = getFields( reader, docId, fieldName );
if( values.length == 0 ) return null;
StringBuilder buffer = new StringBuilder();
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, preTags, postTags, encoder ) );
}
return fragments.toArray( new String[fragments.size()] );
}
@Deprecated
protected String[] getFieldValues( IndexReader reader, int docId, String fieldName) throws IOException {
Document doc = reader.document( docId, new MapFieldSelector( new String[]{ fieldName } ) );
return doc.getValues( fieldName ); // according to Document class javadoc, this never returns null
}
protected Field[] getFields( IndexReader reader, int docId, String fieldName) throws IOException {
// according to javadoc, doc.getFields(fieldName) cannot be used with lazy loaded field???
Document doc = reader.document( docId, new MapFieldSelector( new String[]{ fieldName } ) );
return doc.getFields( fieldName ); // according to Document class javadoc, this never returns null
}
@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,
preTags, postTags, NULL_ENCODER );
}
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,
preTags, postTags, encoder );
}
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( 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( encoder.encodeText( src.substring( srcIndex ) ) );
return fragment.toString();
}
@Deprecated
protected String getFragmentSource( StringBuilder buffer, int[] index, String[] values,
int startOffset, int endOffset ){
while( buffer.length() < endOffset && index[0] < values.length ){
buffer.append( values[index[0]] );
if( values[index[0]].length() > 0 && index[0] + 1 < values.length )
buffer.append( multiValuedSeparator );
index[0]++;
}
int eo = buffer.length() < endOffset ? buffer.length() : endOffset;
return buffer.substring( startOffset, eo );
}
protected String getFragmentSource( StringBuilder buffer, int[] index, Field[] values,
int startOffset, int endOffset ){
while( buffer.length() < endOffset && index[0] < values.length ){
buffer.append( values[index[0]].stringValue() );
if( values[index[0]].isTokenized() && values[index[0]].stringValue().length() > 0 && index[0] + 1 < values.length )
buffer.append( multiValuedSeparator );
index[0]++;
}
int eo = buffer.length() < endOffset ? buffer.length() : endOffset;
return buffer.substring( startOffset, eo );
}
public void setMultiValuedSeparator( char separator ){
multiValuedSeparator = separator;
}
public char getMultiValuedSeparator(){
return multiValuedSeparator;
}
protected String getPreTag( int num ){
return getPreTag( preTags, 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( String[] postTags, int num ){
int n = num % postTags.length;
return postTags[n];
}
}