package org.sipdroid.net.tools;

import java.util.ArrayList;

public abstract class ObjectPool<E> {  

	private ArrayList<Object> locked, unlocked;

	ObjectPool(int size){

		locked = new ArrayList<Object>(size);         

		unlocked = new ArrayList<Object>(size);

	}

	public int getPoolSize() {

		return locked.size() + unlocked.size();

	}

	abstract Object create();

	abstract boolean validate( Object o );

	synchronized Object checkOut(){     

		if(unlocked.size() > 0){

			Object cur = unlocked.get(0);

			unlocked.remove(cur);

			locked.add(cur);           

			return(cur);

		}      

		// no objects available, create a new one

		Object o = create();

		locked.add(o);

		return(o);

	}

	synchronized void checkIn( Object o ) {

		locked.remove( o );

		unlocked.add(o);

	}

}