WordCountExtractor.java

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

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

import java.io.*;
import java.util.*;
import java.net.*;

import edu.northwestern.at.utils.*;

/**	Counts words in a text.
 */

public class WordCountExtractor
{
	/**	The list of words and word counts in the text.
	 *
	 *	<p>
	 *	Key=word<br />
	 *	Value=Integer(count)
	 *	</p>
	 */

	protected Map<String, Integer> wordCounts	=
		new TreeMap<String, Integer>();

	/** The text parsed into a string array of words.
	 *
	 *	Package scope for the benefit of NGramExtractor.
	 */

	String[] words	= null;

	/** String array of unique words. */

	protected String[] uniqueWords	= null;

	/**	Create word count extractor.
	 */

	public WordCountExtractor()
	{
	}

	/**	Extract word counts from a string array of words.
	 *
	 *	@param	words		The string array with the words.
	 */

	public void countWords
	(
		String[] words
	)
	{
		this.words	= (String[])words.clone();

		computeWordCounts();
	}

	/**	Extract word counts from an arraylist of words.
	 *
	 *	@param	wordList	The list with the words.
	 */

	public void countWords
	(
		List<String> wordList
	)
	{
								//	Get the list of words into
								//	a string array.

		int nWords	= wordList.size();

		words		= new String[ nWords ];

		for ( int i = 0 ; i < nWords ; i++ )
		{
			words[ i ]	= wordList.get( i );
		}

		computeWordCounts();
	}

	/**	Compute word counts from a string array of words.
	 */

	protected void computeWordCounts()
	{
								//	Get the count of occurrence
								//	for each word.

		for ( int i = 0 ; i < words.length ; i++ )
		{
			String word	= words[ i ];

			if ( wordCounts.containsKey( word ) )
			{
				int freq	= wordCounts.get( word ).intValue();
				freq++;
				wordCounts.put( word , new Integer( freq ) );
			}
			else
			{
				wordCounts.put( word , new Integer( 1 ) );
			}
		}
		                        //	Create array of unique words.

		int nUniqueWords			= wordCounts.size();

		uniqueWords					= new String[ nUniqueWords ];

		Set<String> keyset			= wordCounts.keySet();
		Iterator<String> iterator	= keyset.iterator();

		for ( int i = 0 ; i < nUniqueWords ; i++ )
		{
			uniqueWords[ i ]	= iterator.next();
		}
	}

	/**	Return tokenized text words as a string array.
	 *
	 *	@return		The string array of words.
	 */

	public String[] getWords()
	{
		return words;
	}

	/**	Return the total number of words.
	 *
	 *	@return		The number of words.
	 */

	public int getNumberOfWords()
	{
		return words.length;
	}

	/**	Return unique words as a string array.
	 *
	 *	@return		The string array of unique words.
	 */

	public String[] getUniqueWords()
	{
		return uniqueWords;
	}

	/**	Return the number of unique words.
	 *
	 *	@return		The number of unique words.
	 */

	public int getNumberOfUniqueWords()
	{
		return uniqueWords.length;
	}

	/**	Return count for a specific word.
	 *
	 *	@param	word	The word whose count is desired.
	 *
	 *	@return			The count of the word in the text.
	 */

	public int getWordCount( String word )
	{
		int result	= 0;

		if ( wordCounts.containsKey( word ) )
		{
			Integer count	= wordCounts.get( word );
			result			= count.intValue();
		}

		return result;
	}

	/**	Return word count map.
	 *
	 *	@return		Word count map.
	 */

	public Map getWordCounts()
	{
		return wordCounts;
	}

	/**	Reset counter.
	 */

	public void reset()
	{
		wordCounts.clear();

		words		= null;
		uniqueWords	= null;
	}
}

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   Northwestern University
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