package net.sf.morph.util;
   
   import java.util.HashMap;
   import java.util.Map;
   
   import net.sf.composite.util.ObjectUtils;
   
   /**
    * @author Matt Sgarlata
   * @since Jan 16, 2005
   */
  public class BidirectionalMap extends HashMap {
  	
  	private final Map reverseMap; 
  
  	public static BidirectionalMap getInstance(Map m) {
  		return m instanceof BidirectionalMap ? (BidirectionalMap) m : new BidirectionalMap(m);
  	}
  
  	public BidirectionalMap() {
  		super();
  		reverseMap = new HashMap();
  	}
  	public BidirectionalMap(int initialCapacity) {
  		super(initialCapacity);
  		reverseMap = new HashMap(initialCapacity);
  	}
  	public BidirectionalMap(int initialCapacity, float loadFactor) {
  		super(initialCapacity, loadFactor);
  		reverseMap = new HashMap(initialCapacity, loadFactor);
  	}
  	public BidirectionalMap(Map m) {
  		this(m.size());
  		putAll(m);
  	}
  	
  	/**
  	 * Retrieves the key that is registered for the given entry
  	 */
  	public Object getKey(Object entry) {
  		return reverseMap.get(entry);
  	}
  	
  	public void clear() {
  		super.clear();
  		reverseMap.clear();
  	}
  	public Object clone() {
  		HashMap clone = (HashMap) super.clone();
  		return new BidirectionalMap(clone);
  	}
  
  	public Object put(Object key, Object value) {
  		if (reverseMap.containsKey(value)) {
  			throw new IllegalArgumentException("The value '"
  				+ ObjectUtils.getObjectDescription(value)
  				+ "' has already been added to the map");
  		}
  		reverseMap.put(value, key);
  		return super.put(key, value);
  	}
  //	public void putAll(Map m) {
  //		super.putAll(m);
  //		if (m != null) {
  //			Iterator keys = m.keySet().iterator();
  //			while (keys != null && keys.hasNext()) {
  //				Object key = keys.next();
  //				Object value = m.get(key);
  //				if (reverseMap.containsKey(value)) {
  //					throw new IllegalArgumentException("Duplicate value "
  //						+ ObjectUtils.getObjectDescription(value)
  //						+ " found in map "
  //						+ ObjectUtils.getObjectDescription(m));
  //				}
  //				reverseMap.put(value, key);
  //			}
  //		}
  //	}
  	public Object remove(Object key) {
  		Object value = get(key);
  		reverseMap.remove(value);
  		return super.remove(key);
  	}
  	
  	public Map getReverseMap() {
  		return reverseMap;
  	}
  }