tikhomirov@195: /*
tikhomirov@195:  * Copyright (c) 2011 TMate Software Ltd
tikhomirov@195:  *  
tikhomirov@195:  * This program is free software; you can redistribute it and/or modify
tikhomirov@195:  * it under the terms of the GNU General Public License as published by
tikhomirov@195:  * the Free Software Foundation; version 2 of the License.
tikhomirov@195:  *
tikhomirov@195:  * This program is distributed in the hope that it will be useful,
tikhomirov@195:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
tikhomirov@195:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
tikhomirov@195:  * GNU General Public License for more details.
tikhomirov@195:  *
tikhomirov@195:  * For information on how to redistribute this software under
tikhomirov@195:  * the terms of a license other than GNU General Public License
tikhomirov@195:  * contact TMate Software at support@hg4j.com
tikhomirov@195:  */
tikhomirov@195: package org.tmatesoft.hg.internal;
tikhomirov@195: 
tikhomirov@195: import java.util.HashMap;
tikhomirov@195: 
tikhomirov@195: /**
tikhomirov@195:  * Instance pooling.
tikhomirov@195:  * 
tikhomirov@195:  * @author Artem Tikhomirov
tikhomirov@195:  * @author TMate Software Ltd.
tikhomirov@195:  */
tikhomirov@195: public class Pool<T> {
tikhomirov@195: 	private final HashMap<T,T> unify = new HashMap<T, T>();
tikhomirov@195: 	
tikhomirov@195: 	public T unify(T t) {
tikhomirov@195: 		T rv = unify.get(t);
tikhomirov@195: 		if (rv == null) {
tikhomirov@195: 			// first time we see a new value
tikhomirov@195: 			unify.put(t, t);
tikhomirov@195: 			rv = t;
tikhomirov@195: 		}
tikhomirov@195: 		return rv;
tikhomirov@195: 	}
tikhomirov@195: }