| /* |
| * 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. |
| */ |
| package org.apache.lucene.search.matchhighlight; |
| |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.List; |
| import org.apache.lucene.analysis.Analyzer; |
| import org.apache.lucene.analysis.TokenStream; |
| import org.apache.lucene.analysis.tokenattributes.OffsetAttribute; |
| import org.apache.lucene.search.MatchesIterator; |
| |
| /** |
| * This strategy works for fields where we know the match occurred but there are no known positions |
| * or offsets. |
| * |
| * <p>We re-analyze field values and return offset ranges for entire values (not individual tokens). |
| * Re-analysis is required because analyzer may return an unknown offset gap. |
| */ |
| public final class OffsetsFromValues implements OffsetsRetrievalStrategy { |
| private final String field; |
| private final Analyzer analyzer; |
| |
| public OffsetsFromValues(String field, Analyzer analyzer) { |
| this.field = field; |
| this.analyzer = analyzer; |
| } |
| |
| @Override |
| public List<OffsetRange> get( |
| MatchesIterator matchesIterator, MatchRegionRetriever.FieldValueProvider doc) |
| throws IOException { |
| List<CharSequence> values = doc.getValues(field); |
| |
| ArrayList<OffsetRange> ranges = new ArrayList<>(); |
| int valueOffset = 0; |
| for (CharSequence charSequence : values) { |
| final String value = charSequence.toString(); |
| |
| TokenStream ts = analyzer.tokenStream(field, value); |
| OffsetAttribute offsetAttr = ts.getAttribute(OffsetAttribute.class); |
| ts.reset(); |
| int startOffset = valueOffset; |
| while (ts.incrementToken()) { |
| // Go through all tokens to increment offset attribute properly. |
| } |
| ts.end(); |
| valueOffset += offsetAttr.endOffset(); |
| ranges.add(new OffsetRange(startOffset, valueOffset)); |
| valueOffset += analyzer.getOffsetGap(field); |
| ts.close(); |
| } |
| return ranges; |
| } |
| |
| @Override |
| public boolean requiresDocument() { |
| return true; |
| } |
| } |