tikhomirov@195: /*
tikhomirov@431:  * Copyright (c) 2011-2012 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@431: import org.tmatesoft.hg.util.Convertor;
tikhomirov@431: 
tikhomirov@195: /**
tikhomirov@195:  * Instance pooling.
tikhomirov@195:  * 
tikhomirov@195:  * @author Artem Tikhomirov
tikhomirov@195:  * @author TMate Software Ltd.
tikhomirov@195:  */
tikhomirov@431: public class Pool<T> implements Convertor<T> {
tikhomirov@262: 	private final HashMap<T,T> unify;
tikhomirov@262: 	
tikhomirov@262: 	public Pool() {
tikhomirov@262: 		unify = new HashMap<T, T>();
tikhomirov@262: 	}
tikhomirov@262: 	
tikhomirov@262: 	public Pool(int sizeHint) {
tikhomirov@262: 		if (sizeHint <= 0) {
tikhomirov@262: 			unify = new HashMap<T, T>();
tikhomirov@262: 		} else {
tikhomirov@262: 			unify = new HashMap<T, T>(sizeHint * 4 / 3, 0.75f);
tikhomirov@262: 		}
tikhomirov@262: 	}
tikhomirov@431: 
tikhomirov@431: 	public T mangle(T t) {
tikhomirov@431: 		return unify(t);
tikhomirov@431: 	}
tikhomirov@431: 
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@196: 	
tikhomirov@262: 	public boolean contains(T t) {
tikhomirov@262: 		return unify.containsKey(t);
tikhomirov@262: 	}
tikhomirov@262: 	
tikhomirov@262: 	public void record(T t) {
tikhomirov@262: 		unify.put(t, t);
tikhomirov@262: 	}
tikhomirov@262: 	
tikhomirov@262: 	public void clear() {
tikhomirov@262: 		unify.clear();
tikhomirov@262: 	}
tikhomirov@262: 
tikhomirov@262: 	public int size() {
tikhomirov@262: 		return unify.size();
tikhomirov@262: 	}
tikhomirov@262: 
tikhomirov@196: 	@Override
tikhomirov@196: 	public String toString() {
tikhomirov@196: 		StringBuilder sb = new StringBuilder();
tikhomirov@196: 		sb.append(Pool.class.getSimpleName());
tikhomirov@196: 		sb.append('<');
tikhomirov@264: 		if (!unify.isEmpty()) {
tikhomirov@264: 			sb.append(unify.keySet().iterator().next().getClass().getName());
tikhomirov@264: 		}
tikhomirov@196: 		sb.append('>');
tikhomirov@196: 		sb.append(':');
tikhomirov@196: 		sb.append(unify.size());
tikhomirov@196: 		return sb.toString();
tikhomirov@196: 	}
tikhomirov@195: }