sketcher2/src/com/jotuntech/sketcher/common/TwoWayHashMap.java

package com.jotuntech.sketcher.common;

import java.util.Collection;
import java.util.IdentityHashMap;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;

import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

/**
 * This map is for storing values with keys. A value can be located
 * with a key and vice versa. This class will assume that no mutations to the keys
 * are made. Values may implement Copyable to get included in copy() operations
 * performed on the map.
 *
 * @author Thor Harald Johansen
 *
 * @param <V> Type of values this map will store
 */
public class TwoWayHashMap<K, V> implements Map<K, V>, Copyable<TwoWayHashMap<K, V>> {
	private Map<K, V> keyMap;
	private Map<V, K> valueMap;
	private List<ChangeListener> changeListeners;
	private Integer autoKey;

	/** Create new integer map */
	public TwoWayHashMap() {
		keyMap = new LinkedHashMap<K, V>();
		valueMap = new IdentityHashMap<V, K>();
		changeListeners = new LinkedList<ChangeListener>();
		autoKey = new Integer(1);
	}

	@SuppressWarnings("unchecked")
	public TwoWayHashMap(TwoWayHashMap<K, V> map) {
		keyMap = new LinkedHashMap<K, V>();
		valueMap = new IdentityHashMap<V, K>();
		changeListeners = new LinkedList<ChangeListener>();
		autoKey = map.autoKey;

		for(Map.Entry<K, V> e : map.keyMap.entrySet()) {
			if(e.getValue() instanceof Copyable<?>) {
				put(e.getKey(), ((Copyable<V>)e.getValue()).copy());
			} else {
				put(e.getKey(), e.getValue());
			}
		}
	}

	/** Insert value into map under specified key */
	public V put(K key, V value) {
		/** Put key into key map, store old value */
		V oldValue = keyMap.put(key, value);

		/** Remove old value from value map */
		valueMap.remove(oldValue);

		/** Put value into value map */
		valueMap.put(value, key);

		/** Notify change listener method */
		change();

		/** Return old value */
		return oldValue;
	}

	/** Insert value into map and auto-assign key
	 *
	 * @return Auto-assigned key
	 */
	@SuppressWarnings("unchecked")
	public K put(V value) {
		/** Put value into map */
		put((K) autoKey, value);

		/** Increment auto key and return previous one */
		return (K) autoKey++;
	}

	/** Remove entry for specified key from map
	 *
	 * @return Entry that was removed, or null if no such entry.
	 */
	public V remove(Object key) {
		/** Remove key from key map, store old value */
		V oldValue = keyMap.remove(key);

		/** Remove old value from value map */
		valueMap.remove(oldValue);

		/** Notify change listener method */
		change();

		/** Return old value */
		return oldValue;
	}

	/** Remove entry for specified value from map
	 *
	 * @return Key of entry that was removed, or null if no such entry.
	 */
	public K removeByValue(V value) {
		/** Remove old value from value map, store old key */
		K oldKey = valueMap.remove(value);

		/** Remove old key from key map */
		keyMap.remove(oldKey);

		/** Notify change listener method */
		change();

		/** Return old key */
		return oldKey;
	}

	/** Get value for specified key */
	public V get(Object key) {
		return keyMap.get(key);
	}

	/** Get key for specified value */
	public K getKeyForValue(V value) {
		return valueMap.get(value);
	}

	/** Get entry set from map */
	public Set<Map.Entry<K, V>> entrySet() {
		return keyMap.entrySet();
	}

	/** Get set of keys from map */
	public Set<K> keySet() {
		return keyMap.keySet();
	}

	/** Get collection of values from map */
	public Collection<V> values() {
		return keyMap.values();
	}

	public void addChangeListener(ChangeListener l) {
		changeListeners.add(l);
	}

	/** Notify listeners of change to map */
	public void change() {
		for(ChangeListener l : changeListeners) {
			l.stateChanged(new ChangeEvent(this));
		}
	}

	public TwoWayHashMap<K, V> copy() {
		return new TwoWayHashMap<K, V>(this);
	}

	public void clear() {
		keyMap.clear();
		valueMap.clear();
		change();
	}

	public void setNextKey(Integer nextKey) {
		this.autoKey = nextKey;
	}

	public Integer getNextKey() {
		return autoKey;
	}

	public boolean containsKey(Object key) {
		return keyMap.containsKey(key);
	}

	public boolean containsValue(Object value) {
		return valueMap.containsKey(value);
	}

	public boolean isEmpty() {
		return keyMap.isEmpty();
	}

	public void putAll(Map<? extends K, ? extends V> m) {
		throw new UnsupportedOperationException();
	}

	public int size() {
		return keyMap.size();
	}
}