package org.apache.lucene.search.spell;
/**
* 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 org.apache.lucene.index.IndexReader;
import java.util.Iterator;
import org.apache.lucene.index.TermEnum;
import org.apache.lucene.index.Term;
import org.apache.lucene.util.StringHelper;
import java.io.*;
/**
* Lucene Dictionary: terms taken from the given field
* of a Lucene index.
*
* When using IndexReader.terms(Term) the code must not call next() on TermEnum
* as the first call to TermEnum, see: http://issues.apache.org/jira/browse/LUCENE-6
*
*
*
*/
public class LuceneDictionary implements Dictionary {
private IndexReader reader;
private String field;
public LuceneDictionary(IndexReader reader, String field) {
this.reader = reader;
this.field = StringHelper.intern(field);
}
public final Iterator<String> getWordsIterator() {
return new LuceneIterator();
}
final class LuceneIterator implements Iterator<String> {
private TermEnum termEnum;
private Term actualTerm;
private boolean hasNextCalled;
LuceneIterator() {
try {
termEnum = reader.terms(new Term(field));
} catch (IOException e) {
throw new RuntimeException(e);
}
}
public String next() {
if (!hasNextCalled) {
hasNext();
}
hasNextCalled = false;
try {
termEnum.next();
} catch (IOException e) {
throw new RuntimeException(e);
}
return (actualTerm != null) ? actualTerm.text() : null;
}
public boolean hasNext() {
if (hasNextCalled) {
return actualTerm != null;
}
hasNextCalled = true;
actualTerm = termEnum.term();
// if there are no words return false
if (actualTerm == null) {
return false;
}
String currentField = actualTerm.field();
// if the next word doesn't have the same field return false
if (currentField != field) {
actualTerm = null;
return false;
}
return true;
}
public void remove() {
throw new UnsupportedOperationException();
}
}
}