package org.apache.lucene.analysis;
/**
* 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.util.AttributeSource;
import java.io.Reader;
import java.io.IOException;
/** A Tokenizer is a TokenStream whose input is a Reader.
<p>
This is an abstract class; subclasses must override {@link #incrementToken()}
<p>
NOTE: Subclasses overriding {@link #incrementToken()} must
call {@link AttributeSource#clearAttributes()} before
setting attributes.
*/
public abstract class Tokenizer extends TokenStream {
/** The text source for this Tokenizer. */
protected Reader input;
/** Construct a tokenizer with null input. */
protected Tokenizer() {}
/** Construct a token stream processing the given input. */
protected Tokenizer(Reader input) {
this.input = CharReader.get(input);
}
/** Construct a tokenizer with null input using the given AttributeFactory. */
protected Tokenizer(AttributeFactory factory) {
super(factory);
}
/** Construct a token stream processing the given input using the given AttributeFactory. */
protected Tokenizer(AttributeFactory factory, Reader input) {
super(factory);
this.input = CharReader.get(input);
}
/** Construct a token stream processing the given input using the given AttributeSource. */
protected Tokenizer(AttributeSource source) {
super(source);
}
/** Construct a token stream processing the given input using the given AttributeSource. */
protected Tokenizer(AttributeSource source, Reader input) {
super(source);
this.input = CharReader.get(input);
}
/** By default, closes the input Reader. */
@Override
public void close() throws IOException {
if (input != null) {
input.close();
// LUCENE-2387: don't hold onto Reader after close, so
// GC can reclaim
input = null;
}
}
/** Return the corrected offset. If {@link #input} is a {@link CharStream} subclass
* this method calls {@link CharStream#correctOffset}, else returns <code>currentOff</code>.
* @param currentOff offset as seen in the output
* @return corrected offset based on the input
* @see CharStream#correctOffset
*/
protected final int correctOffset(int currentOff) {
return (input instanceof CharStream) ? ((CharStream) input).correctOffset(currentOff) : currentOff;
}
/** Expert: Reset the tokenizer to a new reader. Typically, an
* analyzer (in its reusableTokenStream method) will use
* this to re-use a previously created tokenizer. */
public void reset(Reader input) throws IOException {
this.input = input;
}
}