/*
* 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.analysis.icu.segmentation;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.lucene.analysis.util.ResourceLoader;
import org.apache.lucene.analysis.util.ResourceLoaderAware;
import org.apache.lucene.analysis.util.TokenizerFactory;
import org.apache.lucene.util.AttributeFactory;
import org.apache.lucene.util.IOUtils;
import com.ibm.icu.lang.UCharacter;
import com.ibm.icu.lang.UProperty;
import com.ibm.icu.lang.UScript;
import com.ibm.icu.text.BreakIterator;
import com.ibm.icu.text.RuleBasedBreakIterator;
/**
* Factory for {@link ICUTokenizer}.
* Words are broken across script boundaries, then segmented according to
* the BreakIterator and typing provided by the {@link DefaultICUTokenizerConfig}.
*
* <p>
* To use the default set of per-script rules:
*
* <pre class="prettyprint" >
* <fieldType name="text_icu" class="solr.TextField" positionIncrementGap="100">
* <analyzer>
* <tokenizer class="solr.ICUTokenizerFactory"/>
* </analyzer>
* </fieldType></pre>
*
* <p>
* You can customize this tokenizer's behavior by specifying per-script rule files,
* which are compiled by the ICU RuleBasedBreakIterator. See the
* <a href="http://userguide.icu-project.org/boundaryanalysis#TOC-RBBI-Rules"
* >ICU RuleBasedBreakIterator syntax reference</a>.
*
* <p>
* To add per-script rules, add a "rulefiles" argument, which should contain a
* comma-separated list of <tt>code:rulefile</tt> pairs in the following format:
* <a href="http://unicode.org/iso15924/iso15924-codes.html"
* >four-letter ISO 15924 script code</a>, followed by a colon, then a resource
* path. E.g. to specify rules for Latin (script code "Latn") and Cyrillic
* (script code "Cyrl"):
*
* <pre class="prettyprint" >
* <fieldType name="text_icu_custom" class="solr.TextField" positionIncrementGap="100">
* <analyzer>
* <tokenizer class="solr.ICUTokenizerFactory" cjkAsWords="true"
* rulefiles="Latn:my.Latin.rules.rbbi,Cyrl:my.Cyrillic.rules.rbbi"/>
* </analyzer>
* </fieldType></pre>
*/
public class ICUTokenizerFactory extends TokenizerFactory implements ResourceLoaderAware {
static final String RULEFILES = "rulefiles";
private final Map<Integer,String> tailored;
private ICUTokenizerConfig config;
private final boolean cjkAsWords;
private final boolean myanmarAsWords;
/** Creates a new ICUTokenizerFactory */
public ICUTokenizerFactory(Map<String,String> args) {
super(args);
tailored = new HashMap<>();
String rulefilesArg = get(args, RULEFILES);
if (rulefilesArg != null) {
List<String> scriptAndResourcePaths = splitFileNames(rulefilesArg);
for (String scriptAndResourcePath : scriptAndResourcePaths) {
int colonPos = scriptAndResourcePath.indexOf(":");
String scriptCode = scriptAndResourcePath.substring(0, colonPos).trim();
String resourcePath = scriptAndResourcePath.substring(colonPos+1).trim();
tailored.put(UCharacter.getPropertyValueEnum(UProperty.SCRIPT, scriptCode), resourcePath);
}
}
cjkAsWords = getBoolean(args, "cjkAsWords", true);
myanmarAsWords = getBoolean(args, "myanmarAsWords", true);
if (!args.isEmpty()) {
throw new IllegalArgumentException("Unknown parameters: " + args);
}
}
@Override
public void inform(ResourceLoader loader) throws IOException {
assert tailored != null : "init must be called first!";
if (tailored.isEmpty()) {
config = new DefaultICUTokenizerConfig(cjkAsWords, myanmarAsWords);
} else {
final BreakIterator breakers[] = new BreakIterator[UScript.CODE_LIMIT];
for (Map.Entry<Integer,String> entry : tailored.entrySet()) {
int code = entry.getKey();
String resourcePath = entry.getValue();
breakers[code] = parseRules(resourcePath, loader);
}
config = new DefaultICUTokenizerConfig(cjkAsWords, myanmarAsWords) {
@Override
public BreakIterator getBreakIterator(int script) {
if (breakers[script] != null) {
return (BreakIterator) breakers[script].clone();
} else {
return super.getBreakIterator(script);
}
}
// TODO: we could also allow codes->types mapping
};
}
}
private BreakIterator parseRules(String filename, ResourceLoader loader) throws IOException {
StringBuilder rules = new StringBuilder();
InputStream rulesStream = loader.openResource(filename);
BufferedReader reader = new BufferedReader
(IOUtils.getDecodingReader(rulesStream, StandardCharsets.UTF_8));
String line = null;
while ((line = reader.readLine()) != null) {
if ( ! line.startsWith("#"))
rules.append(line);
rules.append('\n');
}
reader.close();
return new RuleBasedBreakIterator(rules.toString());
}
@Override
public ICUTokenizer create(AttributeFactory factory) {
assert config != null : "inform must be called first!";
return new ICUTokenizer(factory, config);
}
}