package org.apache.lucene.analysis.compound;
/**
* 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.File;
import java.io.Reader;
import java.util.Set;
import org.apache.lucene.analysis.Token;
import org.apache.lucene.analysis.TokenFilter; // for javadocs
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.compound.hyphenation.Hyphenation;
import org.apache.lucene.analysis.compound.hyphenation.HyphenationTree;
import org.xml.sax.InputSource;
/**
* A {@link TokenFilter} that decomposes compound words found in many Germanic languages.
* <p>
* "Donaudampfschiff" becomes Donau, dampf, schiff so that you can find
* "Donaudampfschiff" even when you only enter "schiff". It uses a hyphenation
* grammar and a word dictionary to achieve this.
* </p>
*/
public class HyphenationCompoundWordTokenFilter extends
CompoundWordTokenFilterBase {
private HyphenationTree hyphenator;
/**
*
* @param input the {@link TokenStream} to process
* @param hyphenator the hyphenation pattern tree to use for hyphenation
* @param dictionary the word dictionary to match against
* @param minWordSize only words longer than this get processed
* @param minSubwordSize only subwords longer than this get to the output
* stream
* @param maxSubwordSize only subwords shorter than this get to the output
* stream
* @param onlyLongestMatch Add only the longest matching subword to the stream
*/
public HyphenationCompoundWordTokenFilter(TokenStream input,
HyphenationTree hyphenator, String[] dictionary, int minWordSize,
int minSubwordSize, int maxSubwordSize, boolean onlyLongestMatch) {
this(input, hyphenator, makeDictionary(dictionary), minWordSize,
minSubwordSize, maxSubwordSize, onlyLongestMatch);
}
/**
*
* @param input the {@link TokenStream} to process
* @param hyphenator the hyphenation pattern tree to use for hyphenation
* @param dictionary the word dictionary to match against
*/
public HyphenationCompoundWordTokenFilter(TokenStream input,
HyphenationTree hyphenator, String[] dictionary) {
this(input, hyphenator, makeDictionary(dictionary), DEFAULT_MIN_WORD_SIZE,
DEFAULT_MIN_SUBWORD_SIZE, DEFAULT_MAX_SUBWORD_SIZE, false);
}
/**
*
* @param input the {@link TokenStream} to process
* @param hyphenator the hyphenation pattern tree to use for hyphenation
* @param dictionary the word dictionary to match against. If this is a {@link org.apache.lucene.analysis.CharArraySet CharArraySet} it must have set ignoreCase=false and only contain
* lower case strings.
*/
public HyphenationCompoundWordTokenFilter(TokenStream input,
HyphenationTree hyphenator, Set dictionary) {
this(input, hyphenator, dictionary, DEFAULT_MIN_WORD_SIZE,
DEFAULT_MIN_SUBWORD_SIZE, DEFAULT_MAX_SUBWORD_SIZE, false);
}
/**
*
* @param input the {@link TokenStream} to process
* @param hyphenator the hyphenation pattern tree to use for hyphenation
* @param dictionary the word dictionary to match against. If this is a {@link org.apache.lucene.analysis.CharArraySet CharArraySet} it must have set ignoreCase=false and only contain
* lower case strings.
* @param minWordSize only words longer than this get processed
* @param minSubwordSize only subwords longer than this get to the output
* stream
* @param maxSubwordSize only subwords shorter than this get to the output
* stream
* @param onlyLongestMatch Add only the longest matching subword to the stream
*/
public HyphenationCompoundWordTokenFilter(TokenStream input,
HyphenationTree hyphenator, Set dictionary, int minWordSize,
int minSubwordSize, int maxSubwordSize, boolean onlyLongestMatch) {
super(input, dictionary, minWordSize, minSubwordSize, maxSubwordSize,
onlyLongestMatch);
this.hyphenator = hyphenator;
}
/**
* Create a hyphenator tree
*
* @param hyphenationFilename the filename of the XML grammar to load
* @return An object representing the hyphenation patterns
* @throws Exception
*/
public static HyphenationTree getHyphenationTree(String hyphenationFilename)
throws Exception {
return getHyphenationTree(new InputSource(hyphenationFilename));
}
/**
* Create a hyphenator tree
*
* @param hyphenationFile the file of the XML grammar to load
* @return An object representing the hyphenation patterns
* @throws Exception
*/
public static HyphenationTree getHyphenationTree(File hyphenationFile)
throws Exception {
return getHyphenationTree(new InputSource(hyphenationFile.toURL().toExternalForm()));
}
/**
* Create a hyphenator tree
*
* @param hyphenationReader the reader of the XML grammar to load from
* @return An object representing the hyphenation patterns
* @throws Exception
*/
public static HyphenationTree getHyphenationTree(Reader hyphenationReader)
throws Exception {
final InputSource is = new InputSource(hyphenationReader);
// we need this to load the DTD in very old parsers (like the one in JDK 1.4).
// The DTD itsself is provided via EntityResolver, so it should always load, but
// some parsers still want to have a base URL (Crimson).
is.setSystemId("urn:java:" + HyphenationTree.class.getName());
return getHyphenationTree(is);
}
/**
* Create a hyphenator tree
*
* @param hyphenationSource the InputSource pointing to the XML grammar
* @return An object representing the hyphenation patterns
* @throws Exception
*/
public static HyphenationTree getHyphenationTree(InputSource hyphenationSource)
throws Exception {
HyphenationTree tree = new HyphenationTree();
tree.loadPatterns(hyphenationSource);
return tree;
}
@Override
protected void decomposeInternal(final Token token) {
// get the hyphenation points
Hyphenation hyphens = hyphenator.hyphenate(token.termBuffer(), 0, token
.termLength(), 1, 1);
// No hyphen points found -> exit
if (hyphens == null) {
return;
}
final int[] hyp = hyphens.getHyphenationPoints();
char[] lowerCaseTermBuffer=makeLowerCaseCopy(token.termBuffer());
for (int i = 0; i < hyp.length; ++i) {
int remaining = hyp.length - i;
int start = hyp[i];
Token longestMatchToken = null;
for (int j = 1; j < remaining; j++) {
int partLength = hyp[i + j] - start;
// if the part is longer than maxSubwordSize we
// are done with this round
if (partLength > this.maxSubwordSize) {
break;
}
// we only put subwords to the token stream
// that are longer than minPartSize
if (partLength < this.minSubwordSize) {
continue;
}
// check the dictionary
if (dictionary.contains(lowerCaseTermBuffer, start, partLength)) {
if (this.onlyLongestMatch) {
if (longestMatchToken != null) {
if (longestMatchToken.termLength() < partLength) {
longestMatchToken = createToken(start, partLength, token);
}
} else {
longestMatchToken = createToken(start, partLength, token);
}
} else {
tokens.add(createToken(start, partLength, token));
}
} else if (dictionary.contains(lowerCaseTermBuffer, start,
partLength - 1)) {
// check the dictionary again with a word that is one character
// shorter
// to avoid problems with genitive 's characters and other binding
// characters
if (this.onlyLongestMatch) {
if (longestMatchToken != null) {
if (longestMatchToken.termLength() < partLength - 1) {
longestMatchToken = createToken(start, partLength - 1, token);
}
} else {
longestMatchToken = createToken(start, partLength - 1, token);
}
} else {
tokens.add(createToken(start, partLength - 1, token));
}
}
}
if (this.onlyLongestMatch && longestMatchToken!=null) {
tokens.add(longestMatchToken);
}
}
}
}