/*
* 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.tuscany.sca.domain.search.impl;
import java.io.IOException;
import java.io.StringReader;
import java.util.Map;
import org.apache.lucene.analysis.CachingTokenFilter;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.highlight.Fragmenter;
import org.apache.lucene.search.highlight.Highlighter;
import org.apache.lucene.search.highlight.InvalidTokenOffsetsException;
import org.apache.lucene.search.highlight.NullFragmenter;
import org.apache.lucene.search.highlight.SimpleFragmenter;
import org.apache.lucene.search.highlight.QueryScorer;
import org.apache.tuscany.sca.domain.search.Result;
/**
* @version $Rev: 885247 $ $Date: 2009-11-29 17:14:59 +0000 (Sun, 29 Nov 2009) $
*/
final public class HighlightingUtil {
public static void highlightResult(Result result, Query query) {
highlightResult(result, query, new SimpleFragmenter(70));
}
public static void highlightResult(Result result, Query query, Fragmenter fragmenter) {
Map<String, Result> contents = result.getContents();
if (contents != null) {
for (Result content : contents.values()) {
highlightResult(content, query, fragmenter);
}
}
String highlightedText =
HighlightingUtil.bestFragmentHighlighted(result.getField(), query, result.getValue(), fragmenter);
// checks if something was highlighted before resetting the value
if (highlightedText != null && highlightedText.length() > 0) {
result.setValue(highlightedText);
}
}
public static String highlight(String field, Query query, String text) {
String highlightedText = bestFragmentHighlighted(field, query, text, new NullFragmenter());
if (highlightedText == null || text.length() >= highlightedText.length()) {
return text;
}
return highlightedText;
}
public static String bestFragmentHighlighted(String field, Query query, String text) throws IOException {
return bestFragmentHighlighted(field, query, text, new SimpleFragmenter(100));
}
public static String bestFragmentHighlighted(String field, Query query, String text, Fragmenter fragmenter) {
try {
CachingTokenFilter tokenStream =
new CachingTokenFilter(new DomainSearchAnalyzer().tokenStream(field, new StringReader(text)));
QueryScorer scorer = new QueryScorer(query, field, "");
scorer.init(tokenStream);
Highlighter highlighter =
new Highlighter(new DomainSearchFormatter(), scorer);
highlighter.setTextFragmenter(fragmenter);
tokenStream.reset();
try {
return highlighter.getBestFragments(tokenStream, text, 2, " ... ");
} catch (InvalidTokenOffsetsException e) {
// could not create fragments, return empty string
}
} catch (IOException ex) {
// should never happen
}
return "";
}
public static String replaceHighlightMarkupBy(CharSequence text, String startHighlight, String endHighlight) {
StringBuilder sb = new StringBuilder();
int start = 0;
int end = 0;
for (int i = 0; i < text.length(); i++) {
char c = text.charAt(i);
if (start > 0) {
if (c == DomainSearchFormatter.HIGHLIGHT_START.charAt(start)) {
start++;
if (start == DomainSearchFormatter.HIGHLIGHT_START.length()) {
sb.append(startHighlight);
start = 0;
}
} else {
for (int j = 0; j < start; j++) {
sb.append(DomainSearchFormatter.HIGHLIGHT_START.charAt(j));
}
start = 0;
}
} else if (end > 0) {
if (c == DomainSearchFormatter.HIGHLIGHT_END.charAt(end)) {
end++;
if (end == DomainSearchFormatter.HIGHLIGHT_END.length()) {
sb.append(endHighlight);
end = 0;
}
} else {
for (int j = 0; j < end; j++) {
sb.append(DomainSearchFormatter.HIGHLIGHT_END.charAt(j));
}
end = 0;
}
} else if (c == DomainSearchFormatter.HIGHLIGHT_START.charAt(0)) {
start = 1;
} else if (c == DomainSearchFormatter.HIGHLIGHT_END.charAt(0)) {
end = 1;
} else {
sb.append(c);
}
}
if (start > 0) {
for (int j = 0; j < start; j++) {
sb.append(DomainSearchFormatter.HIGHLIGHT_START.charAt(j));
}
} else if (end > 0) {
for (int j = 0; j < start; j++) {
sb.append(DomainSearchFormatter.HIGHLIGHT_END.charAt(j));
}
}
return sb.toString();
}
}