HashMapArrayList.java

/**
 * 
 */
package ecologylab.generic;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

/**
 * A HashMap with an ArrayList backing store, for speedy linear and hashed access.
 * 
 * @author andruid
 *
 */
public class HashMapArrayList<K, V> extends HashMap<K, V> implements Iterable<V>
{
	protected	final	ArrayList<V>	arrayList;
	
	/**
	 * 
	 */
	public HashMapArrayList()
	{
		arrayList	= new ArrayList<V>();
	}

	/**
	 * @param arg0
	 */
	public HashMapArrayList(int arg0)
	{
		super(arg0);
		arrayList	= new ArrayList<V>(arg0);
	}

	/**
	 * @param arg0
	 */
	public HashMapArrayList(Map arg0)
	{
		super(arg0);
		arrayList	= new ArrayList<V>(arg0.size());
	}

	/**
	 * @param arg0
	 * @param arg1
	 */
	public HashMapArrayList(int arg0, float arg1)
	{
		super(arg0, arg1);
		arrayList	= new ArrayList<V>(arg0);
	}

	@Override public V put(K key, V value)
	{
		V result	= super.put(key, value);
		if (result != null)	// the object that was overridden
			arrayList.remove(result);
		arrayList.add(value);
		
		return result;
	}
	
	@Override public void putAll(Map<? extends K, ? extends V> map)
	{
		for (K key : map.keySet())
			this.put(key, map.get(key));
	}
	
	public V get(int index)
	{
		return arrayList.get(index);
	}
	
	@Override
	public Iterator<V> iterator()
	{
		return arrayList.iterator();
	}
	
	@Override public V remove(Object key)
	{
		V result	= super.remove(key);
		if (result != null)
			arrayList.remove(result);
		return result;
	}
	
	@Override public void clear()
	{
		super.clear();
		arrayList.clear();
	}
	
	public void recycle()
	{
		super.clear();
		int last	= arrayList.size() - 1;
		for (int i=last; i>=0; i--)
		{
			V that	= arrayList.remove(i);
			// that.recycle() -- must enforce that implements Recyclable
		}
	}
	
	@Override public Collection<V> values()
	{
		return arrayList;
	}
}