| /* |
| * 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; |
| |
| |
| import java.io.IOException; |
| import java.io.Reader; |
| |
| import org.apache.lucene.util.AttributeFactory; |
| import org.apache.lucene.util.AttributeSource; |
| |
| /** 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 = ILLEGAL_STATE_READER; |
| |
| /** Pending reader: not actually assigned to input until reset() */ |
| private Reader inputPending = ILLEGAL_STATE_READER; |
| |
| /** |
| * Construct a tokenizer with no input, awaiting a call to {@link #setReader(java.io.Reader)} |
| * to provide input. |
| */ |
| protected Tokenizer() { |
| // |
| } |
| |
| /** |
| * Construct a tokenizer with no input, awaiting a call to {@link #setReader(java.io.Reader)} to |
| * provide input. |
| * @param factory attribute factory. |
| */ |
| protected Tokenizer(AttributeFactory factory) { |
| super(factory); |
| } |
| |
| /** |
| * {@inheritDoc} |
| * <p> |
| * <b>NOTE:</b> |
| * The default implementation closes the input Reader, so |
| * be sure to call <code>super.close()</code> when overriding this method. |
| */ |
| @Override |
| public void close() throws IOException { |
| input.close(); |
| // LUCENE-2387: don't hold onto Reader after close, so |
| // GC can reclaim |
| inputPending = input = ILLEGAL_STATE_READER; |
| } |
| |
| /** Return the corrected offset. If {@link #input} is a {@link CharFilter} subclass |
| * this method calls {@link CharFilter#correctOffset}, else returns <code>currentOff</code>. |
| * @param currentOff offset as seen in the output |
| * @return corrected offset based on the input |
| * @see CharFilter#correctOffset |
| */ |
| protected final int correctOffset(int currentOff) { |
| return (input instanceof CharFilter) ? ((CharFilter) input).correctOffset(currentOff) : currentOff; |
| } |
| |
| /** Expert: Set a new reader on the Tokenizer. Typically, an |
| * analyzer (in its tokenStream method) will use |
| * this to re-use a previously created tokenizer. */ |
| public final void setReader(Reader input) { |
| if (input == null) { |
| throw new NullPointerException("input must not be null"); |
| } else if (this.input != ILLEGAL_STATE_READER) { |
| throw new IllegalStateException("TokenStream contract violation: close() call missing"); |
| } |
| this.inputPending = input; |
| setReaderTestPoint(); |
| } |
| |
| @Override |
| public void reset() throws IOException { |
| super.reset(); |
| input = inputPending; |
| inputPending = ILLEGAL_STATE_READER; |
| } |
| |
| // only used for testing |
| void setReaderTestPoint() {} |
| |
| private static final Reader ILLEGAL_STATE_READER = new Reader() { |
| @Override |
| public int read(char[] cbuf, int off, int len) { |
| throw new IllegalStateException("TokenStream contract violation: reset()/close() call missing, " + |
| "reset() called multiple times, or subclass does not call super.reset(). " + |
| "Please see Javadocs of TokenStream class for more information about the correct consuming workflow."); |
| } |
| |
| @Override |
| public void close() {} |
| }; |
| } |
| |