org.apache.solr.highlight.RegexFragmenter Maven / Gradle / Ivy
/*
* 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.solr.highlight;
import java.util.regex.Pattern;
import org.apache.lucene.search.highlight.Fragmenter;
import org.apache.lucene.search.highlight.NullFragmenter;
import org.apache.solr.common.params.HighlightParams;
import org.apache.solr.common.params.SolrParams;
import org.apache.solr.common.util.NamedList;
/**
* {@link org.apache.lucene.search.highlight.Fragmenter} that tries to produce snippets that "look" like a regular
* expression.
*
* solrconfig.xml
parameters:
*
* hl.regex.pattern
: regular expression corresponding to "nice" fragments.
* hl.regex.slop
: how far the fragmenter can stray from the ideal fragment size.
A slop of 0.2 means that the fragmenter can go over or under by 20%.
* hl.regex.maxAnalyzedChars
: how many characters to apply the
regular expression to (independent from the global highlighter setting).
*
*
* NOTE: the default for maxAnalyzedChars
is much lower for this
* fragmenter. After this limit is exhausted, fragments are produced in the
* same way as GapFragmenter
*/
public class RegexFragmenter extends HighlightingPluginBase implements SolrFragmenter
{
protected String defaultPatternRaw;
protected Pattern defaultPattern;
@Override
public void init(NamedList args) {
super.init(args);
defaultPatternRaw = LuceneRegexFragmenter.DEFAULT_PATTERN_RAW;
if( defaults != null ) {
defaultPatternRaw = defaults.get(HighlightParams.PATTERN, LuceneRegexFragmenter.DEFAULT_PATTERN_RAW);
}
defaultPattern = Pattern.compile(defaultPatternRaw);
}
@Override
public Fragmenter getFragmenter(String fieldName, SolrParams params )
{
numRequests.inc();
params = SolrParams.wrapDefaults(params, defaults);
int fragsize = params.getFieldInt( fieldName, HighlightParams.FRAGSIZE, LuceneRegexFragmenter.DEFAULT_FRAGMENT_SIZE );
int increment = params.getFieldInt( fieldName, HighlightParams.INCREMENT, LuceneRegexFragmenter.DEFAULT_INCREMENT_GAP );
float slop = params.getFieldFloat( fieldName, HighlightParams.SLOP, LuceneRegexFragmenter.DEFAULT_SLOP );
int maxchars = params.getFieldInt( fieldName, HighlightParams.MAX_RE_CHARS, LuceneRegexFragmenter.DEFAULT_MAX_ANALYZED_CHARS );
String rawpat = params.getFieldParam( fieldName, HighlightParams.PATTERN, LuceneRegexFragmenter.DEFAULT_PATTERN_RAW );
Pattern p = rawpat == defaultPatternRaw ? defaultPattern : Pattern.compile(rawpat);
if( fragsize <= 0 ) {
return new NullFragmenter();
}
return new LuceneRegexFragmenter( fragsize, increment, slop, maxchars, p );
}
///////////////////////////////////////////////////////////////////////
//////////////////////// SolrInfoMBeans methods ///////////////////////
///////////////////////////////////////////////////////////////////////
@Override
public String getDescription() {
return "RegexFragmenter (" + defaultPatternRaw + ")";
}
}