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

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

import java.util.*;
import com.ibm.icu.text.BreakIterator;

import edu.northwestern.at.utils.*;

/**	Simple word tokenizer which splits on whitespace only. */

public class ICU4JBreakIteratorWordTokenizer
	extends AbstractWordTokenizer
	implements WordTokenizer
{
	/**	Locale. */

	protected Locale locale	= Locale.US;

	/**	Create a word tokenizer that uses the ICU4J word break iterator.
	 */

	public ICU4JBreakIteratorWordTokenizer()
	{
		super();
	}

	/**	Create a word tokenizer that uses the ICU4J word break iterator.
	 *
	 *	@param	locale	Locale to use for tokenization.
	 */

	public ICU4JBreakIteratorWordTokenizer( Locale locale )
	{
		super();

		this.locale	= locale;
	}

	/**	Break text into word tokens.
	 *
	 *	@param	text			Text to break into word tokens.
	 *
	 *	@return					Input text broken into list of tokens.
	 */

	 public List<String> extractWords( String text )
	 {
								//	Create list to hold extracted tokens.

	 	List<String> result	= ListFactory.createNewList();

								//	Create a word-based break iterator.

		BreakIterator wordIterator =
			BreakIterator.getWordInstance( locale );

								//	Set the text to tokenize into the
								//	break iterator.

		String fixedText	= preTokenizer.pretokenize( text );

		wordIterator.setText( fixedText );

								//	Find the start and end of the
								//	first token.

		int start	= wordIterator.first();
		int end		= wordIterator.next();

								//	While there are tokens left to
								//	extract ...

		while ( end != BreakIterator.DONE )
		{
								//	Get text for next token.

			String token	= fixedText.substring( start , end );

								//	Add token to result list if token
								//	is not whitespace.

			if ( !Character.isWhitespace( token.charAt( 0 ) ) )
			{
				token	= preprocessToken( token , result );

								//	If the token is not empty,
								//	add it to the sentence.

				if ( token.length() > 0 )
				{
								//	Check if we need to split a token
								//	containing an internal period.

					String[] tokens	= splitToken( token );

					for ( int k = 0 ; k < tokens.length ; k++ )
					{
						if ( tokens[ k ].length() > 0 )
						{
							addWordToSentence( result ,  tokens[ k ] );
						}
					}
				}
			}
								//	Find start and end of next token
								//	if any.
			start	= end;
			end		= wordIterator.next();
		}
								//	Return result.
		return result;
	 }
}

/*
Copyright (c) 2008, 2009 by Northwestern University.
All rights reserved.

Developed by:
   Academic and Research Technologies
   Northwestern University
   http://www.it.northwestern.edu/about/departments/at/

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal with the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or
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.

    * Neither the names of Academic and Research Technologies,
      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.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE CONTRIBUTORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE SOFTWARE.
*/