code: /*
   * Copyright (C) 2007 by
   * 
   * 	Xuan-Hieu Phan
   *	hieuxuan@ecei.tohoku.ac.jp or pxhieu@gmail.com
   * 	Graduate School of Information Sciences
   * 	Tohoku University
   * 
   *  Cam-Tu Nguyen
   *  ncamtu@gmail.com
   *  College of Technology
   *  Vietnam National University, Hanoi
   *
   * JGibbsLDA is a free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published
   * by the Free Software Foundation; either version 2 of the License,
   * or (at your option) any later version.
   *
   * JGibbsLDA is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with JGibbsLDA; if not, write to the Free Software Foundation,
   * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
   */
  package jgibbslda;
  
  import java.io.BufferedReader;
  import java.io.BufferedWriter;
  import java.io.FileInputStream;
  import java.io.FileOutputStream;
  import java.io.InputStreamReader;
  import java.io.OutputStreamWriter;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.Map;
  import java.util.StringTokenizer;
  
  public class Dictionary {
  	public Map<String,Integer> word2id;
  	public Map<Integer, String> id2word;
  		
  	//--------------------------------------------------
  	// constructors
  	//--------------------------------------------------
  	
  	public Dictionary(){
  		word2id = new HashMap<String, Integer>();
  		id2word = new HashMap<Integer, String>();
  	}
  	
  	//---------------------------------------------------
  	// get/set methods
  	//---------------------------------------------------
  	
  	public String getWord(int id){
  		return id2word.get(id);
  	}
  	
  	public Integer getID (String word){
  		return word2id.get(word);
  	}
  	
  	//----------------------------------------------------
  	// checking methods
  	//----------------------------------------------------
  	/**
  	 * check if this dictionary contains a specified word
  	 */
  	public boolean contains(String word){
  		return word2id.containsKey(word);
  	}
  	
  	public boolean contains(int id){
  		return id2word.containsKey(id);
  	}
  	//---------------------------------------------------
  	// manupulating methods
  	//---------------------------------------------------
  	/**
  	 * add a word into this dictionary
  	 * return the corresponding id
  	 */
  	public int addWord(String word){
  		if (!contains(word)){
  			int id = word2id.size();
  			
  			word2id.put(word, id);
  			id2word.put(id,word);
  			
  			return id;
  		}
  		else return getID(word);		
  	}
  	
  	//---------------------------------------------------
  	// I/O methods
  	//---------------------------------------------------
  	/**
  	 * read dictionary from file
  	 */
  	public boolean readWordMap(String wordMapFile){		
  		try{
  			BufferedReader reader = new BufferedReader(new InputStreamReader(
  					new FileInputStream(wordMapFile), "UTF-8"));
  			String line;
  			
  			//read the number of words
  			line = reader.readLine();			
  			int nwords = Integer.parseInt(line);
  			
  			//read map
  			for (int i = 0; i < nwords; ++i){
  				line = reader.readLine();
  				StringTokenizer tknr = new StringTokenizer(line, " \t\n\r");
  				
  				if (tknr.countTokens() != 2) continue;
  				
  				String word = tknr.nextToken();
  				String id = tknr.nextToken();
  				int intID = Integer.parseInt(id);
  				
  				id2word.put(intID, word);
  				word2id.put(word, intID);
  			}
  			
  			reader.close();
  			return true;
  		}
  		catch (Exception e){
  			System.out.println("Error while reading dictionary:" + e.getMessage());
  			e.printStackTrace();
  			return false;
  		}		
  	}
  	
  	public boolean writeWordMap(String wordMapFile){
  		try{
  			BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(
  					new FileOutputStream(wordMapFile), "UTF-8"));
  			
  			//write number of words
  			writer.write(word2id.size() + "\n");
  			
  			//write word to id
  			Iterator<String> it = word2id.keySet().iterator();
  			while (it.hasNext()){
  				String key = it.next();
  				Integer value = word2id.get(key);
  				
  				writer.write(key + " " + value + "\n");
  			}
  			
  			writer.close();
  			return true;
  		}
  		catch (Exception e){
  			System.out.println("Error while writing word map " + e.getMessage());
  			e.printStackTrace();
  			return false;
  		}
  		
  		
  	}
  }
  