/*
* 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.mahout.common.lucene;
import com.google.common.collect.AbstractIterator;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import java.io.IOException;
/**
* Provide an Iterator for the tokens in a TokenStream.
*/
//TODO: consider using the char/byte arrays instead of strings, esp. when we upgrade to Lucene 4.0
public final class TokenStreamIterator extends AbstractIterator<String> {
private final TokenStream tokenStream;
public TokenStreamIterator(TokenStream tokenStream) {
this.tokenStream = tokenStream;
}
@Override
protected String computeNext() {
try {
if (tokenStream.incrementToken()) {
return tokenStream.getAttribute(CharTermAttribute.class).toString();
} else {
return endOfData();
}
} catch (IOException e) {
throw new IllegalStateException("IO error while tokenizing", e);
}
}
}