BreakIteratorSentenceSplitterIterator.java

package edu.northwestern.at.utils.corpuslinguistics.sentencesplitter;

/*	Please see the license information at the end of this file. */

import java.text.BreakIterator;
import java.util.Locale;

/**	BreakIterator-based sentence splitter iterator. */

public class BreakIteratorSentenceSplitterIterator
	implements SentenceSplitterIterator
{
	/**	BreakIterator used to iterate over sentences.
	 */

	protected BreakIterator sentenceExtractor;

	/**	Start of current sentence. */

	protected int start	= BreakIterator.DONE;

	/**	End of current sentence. */

	protected int end	= BreakIterator.DONE;

	/**	Text to break up. */

	protected String text;

	/**	Create sentence iterator.
	 */

	public BreakIteratorSentenceSplitterIterator()
	{
		sentenceExtractor	=
			BreakIterator.getSentenceInstance( Locale.US );
	}

	/**	Create sentence iterator with specified locale.
	 *
	 *	@param	locale	The locale.
	 */

	public BreakIteratorSentenceSplitterIterator( Locale locale )
	{
		sentenceExtractor	=
			BreakIterator.getSentenceInstance( locale );
	}

	/**	Create sentence iterator over text.
	 *
	 *	@param	text	The text from which to extract sentences.
	 */

	public BreakIteratorSentenceSplitterIterator( String text )
	{
		sentenceExtractor	=
			BreakIterator.getSentenceInstance( Locale.US );

		setText( text );
	}

	/**	Create sentence iterator over text with specified locale.
	 *
	 *	@param	text	The text from which to extract sentences.
	 *	@param	locale	The locale.
	 */

	public BreakIteratorSentenceSplitterIterator( String text , Locale locale )
	{
		sentenceExtractor	=
			BreakIterator.getSentenceInstance( locale );

		setText( text );
	}

	/**	Set the text to split.
	 *
	 *	@param	text	Text to split.
	 */

	public void setText( String text )
	{
		this.text	= text;

		sentenceExtractor.setText( this.text );

		start	= sentenceExtractor.first();
		end 	= sentenceExtractor.next();
	}

	/**	Check if there is another sentence available.
	 *
	 *	@return	true if another sentence is available.
	 */

	public boolean hasNext()
	{
		return ( end != BreakIterator.DONE );
	}

	/**	Return next sentence.
	 *
	 *	@return	next sentence, or null if none.
	 */

	public String next()
	{
		String result	= null;

		if ( end != BreakIterator.DONE )
		{
			result	= text.substring( start , end );
			start	= end;
			end 	= sentenceExtractor.next();
		}

		return result;
	}

	/**	Return next sentence without advancing sentence pointer.
	 *
	 *	@return	next sentence, or null if none.
	 */

	public String peek()
	{
		String result	= null;

		if ( end != BreakIterator.DONE )
		{
			result	= text.substring( start , end );
		}

		return result;
	}
}

/*
Copyright (c) 2008, 2009 by Northwestern University.
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Developed by:
   Academic and Research Technologies
   Northwestern University
   http://www.it.northwestern.edu/about/departments/at/

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obtaining a copy of this software and associated documentation
files (the "Software"), to deal with the Software without
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sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimers.

    * Redistributions in binary form must reproduce the above
      copyright notice, this list of conditions and the following
      disclaimers in the documentation and/or other materials provided
      with the distribution.

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      Northwestern University, nor the names of its contributors may be
      used to endorse or promote products derived from this Software
      without specific prior written permission.

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