/**
 * 
 */
package vroom.common.utilities;

import java.util.HashMap;
import java.util.Map;

/**
 * <code>BiHashMap</code> is a simple implementation of a two-dimension {@linkplain HashMap hash map}
 * <p>
 * Creation date: 5 juil. 2010 - 20:13:24
 * 
 * @author Victor Pillac, <a href="http://uniandes.edu.co">Universidad de Los Andes</a>-<a
 *         href="http://copa.uniandes.edu.co">Copa</a> <a href="http://www.emn.fr">Ecole des Mines de Nantes</a>-<a
 *         href="http://www.irccyn.ec-nantes.fr/irccyn/d/en/equipes/Slp">SLP</a>
 * @version 1.0
 */
public class BiHashMap<K1, K2, V> {

    private final Map<K1, Map<K2, V>> mMap;

    public BiHashMap() {
        mMap = new HashMap<K1, Map<K2, V>>();
    }

    /**
     * Associates the specified value with the specified keys in this map (optional operation). If the map previously
     * contained a mapping for the key, the old value is replaced by the specified value.
     * 
     * @param key1
     *            the first key
     * @param key2
     *            the second key
     * @param value
     *            the value to be set
     * @return the value previously associated with (key1,key2), or <code>null</code> if none
     * @see Map#put(Object, Object)
     */
    public V put(K1 key1, K2 key2, V value) {
        Map<K2, V> map;
        if (mMap.containsKey(key1)) {
            map = mMap.get(key1);
        } else {
            map = new HashMap<K2, V>();
            mMap.put(key1, map);
        }

        return map.put(key2, value);
    }

    /**
     * Returns the value to which the specified key is mapped, or <code>null</code> if this map contains no mapping for
     * the key.
     * 
     * @param key1
     *            the first key whose associated value is to be returned
     * @param key2
     *            the second key whose associated value is to be returned
     * @return the value to which the specified key is mapped, or <code>null</code> if this map contains no mapping for
     *         the key
     * @see Map#get(Object)
     */
    public V get(K1 key1, K2 key2) {
        if (mMap.containsKey(key1)) {
            return mMap.get(key1).get(key2);
        } else {
            return null;
        }
    }

    /**
     * Returns <code>true</code> if this map contains a mapping for the specified key
     * 
     * @param key1
     *            the first key whose presence in this map is to be tested
     * @param key2
     *            the second key whose presence in this map is to be tested
     * @return Returns true if this map contains a mapping for the specified key
     * @see Map#containsKey(Object)
     */
    public boolean containsKeys(K1 key1, K2 key2) {
        return mMap.containsKey(key1) && mMap.get(key1).containsKey(key2);
    }

    public void clear() {
        mMap.clear();
    }

}