org.apache.lucene.analysis.core.KeywordTokenizer.java Source code

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Here is the source code for org.apache.lucene.analysis.core.KeywordTokenizer.java

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/*
 * 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.core;

import java.io.IOException;

import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.util.AttributeFactory;

import static org.apache.lucene.analysis.standard.StandardTokenizer.MAX_TOKEN_LENGTH_LIMIT;

/**
 * Emits the entire input as a single token.
 */
public final class KeywordTokenizer extends Tokenizer {
    /** Default read buffer size */
    public static final int DEFAULT_BUFFER_SIZE = 256;

    private boolean done = false;
    private int finalOffset;
    private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
    private OffsetAttribute offsetAtt = addAttribute(OffsetAttribute.class);

    public KeywordTokenizer() {
        this(DEFAULT_BUFFER_SIZE);
    }

    public KeywordTokenizer(int bufferSize) {
        if (bufferSize > MAX_TOKEN_LENGTH_LIMIT || bufferSize <= 0) {
            throw new IllegalArgumentException("maxTokenLen must be greater than 0 and less than "
                    + MAX_TOKEN_LENGTH_LIMIT + " passed: " + bufferSize);
        }
        termAtt.resizeBuffer(bufferSize);
    }

    public KeywordTokenizer(AttributeFactory factory, int bufferSize) {
        super(factory);
        if (bufferSize > MAX_TOKEN_LENGTH_LIMIT || bufferSize <= 0) {
            throw new IllegalArgumentException("maxTokenLen must be greater than 0 and less than "
                    + MAX_TOKEN_LENGTH_LIMIT + " passed: " + bufferSize);
        }
        termAtt.resizeBuffer(bufferSize);
    }

    @Override
    public final boolean incrementToken() throws IOException {
        if (!done) {
            clearAttributes();
            done = true;
            int upto = 0;
            char[] buffer = termAtt.buffer();
            while (true) {
                final int length = input.read(buffer, upto, buffer.length - upto);
                if (length == -1)
                    break;
                upto += length;
                if (upto == buffer.length)
                    buffer = termAtt.resizeBuffer(1 + buffer.length);
            }
            termAtt.setLength(upto);
            finalOffset = correctOffset(upto);
            offsetAtt.setOffset(correctOffset(0), finalOffset);
            return true;
        }
        return false;
    }

    @Override
    public final void end() throws IOException {
        super.end();
        // set final offset 
        offsetAtt.setOffset(finalOffset, finalOffset);
    }

    @Override
    public void reset() throws IOException {
        super.reset();
        this.done = false;
    }
}