simplefragmenter.java

lucene2.2.0版本

package org.apache.lucene.search.highlight;
/**
 * 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.analysis.Token;

/**
 * {@link Fragmenter} implementation which breaks text up into same-size 
 * fragments with no concerns over spotting sentence boundaries.
 * @author [e-mail]
 */
public class SimpleFragmenter implements Fragmenter
{
	private static final int DEFAULT_FRAGMENT_SIZE =100;
	private int currentNumFrags;
	private int fragmentSize;


	public SimpleFragmenter()
	{
		this(DEFAULT_FRAGMENT_SIZE);
	}


	/**
	 * 
	 * @param fragmentSize size in bytes of each fragment
	 */
	public SimpleFragmenter(int fragmentSize)
	{
		this.fragmentSize=fragmentSize;
	}

	/* (non-Javadoc)
	 * @see org.apache.lucene.search.highlight.TextFragmenter#start(java.lang.String)
	 */
	public void start(String originalText)
	{
		currentNumFrags=1;
	}

	/* (non-Javadoc)
	 * @see org.apache.lucene.search.highlight.TextFragmenter#isNewFragment(org.apache.lucene.analysis.Token)
	 */
	public boolean isNewFragment(Token token)
	{
		boolean isNewFrag= token.endOffset()>=(fragmentSize*currentNumFrags);
		if(isNewFrag)
		{
			currentNumFrags++;
		}
		return isNewFrag;
	}

	/**
	 * @return size in bytes of each fragment
	 */
	public int getFragmentSize()
	{
		return fragmentSize;
	}

	/**
	 * @param size size in bytes of each fragment
	 */
	public void setFragmentSize(int size)
	{
		fragmentSize = size;
	}

}