/*
 * Rapid Beans Framework: ThreadLocalProperties.java
 * 
 * Copyright (C) 2009 Martin Bluemel
 * 
 * Creation Date: 02/25/2006
 * 
 * This program is free software; you can redistribute it and/or modify it under the terms of the
 * GNU Lesser General Public License as published by the Free Software Foundation;
 * either version 3 of the License, or (at your option) any later version.
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Lesser General Public License for more details.
 * You should have received a copies of the GNU Lesser General Public License and the
 * GNU General Public License along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

package org.rapidbeans.core.common;

import java.util.Hashtable;

/**
 * thread local hack to fine tune program behavior.
 * 
 * @author Martin Bluemel
 */
public final class ThreadLocalProperties {

	/**
	 * Thread hack.
	 */
	private static ThreadLocal<Hashtable<String, Object>> props = new ThreadLocal<Hashtable<String, Object>>() {
		protected synchronized Hashtable<String, Object> initialValue() {
			return new Hashtable<String, Object>();
		}
	};

	/**
	 * set the property.
	 * 
	 * @param key
	 *            the property's key
	 * @param value
	 *            the property's value
	 * 
	 * @return if the property has been set successfully
	 */
	public static boolean set(final String key, final Object value) {
		boolean accepted = false;
		// once a property is set it can not be set
		if (props.get().get(key) == null) {
			props.get().put(key, value);
			accepted = true;
		}
		return accepted;
	}

	/**
	 * unset the thread local property.
	 * 
	 * @param key
	 *            the thread local property's key
	 */
	public static void unset(final String key) {
		props.get().remove(key);
	}

	/**
	 * get a thread local property value for a certain key.
	 * 
	 * @param key
	 *            the thread local property's key
	 * 
	 * @return the property value
	 */
	public static Object get(final String key) {
		return props.get().get(key);
	}

	/**
	 * prevent from being constructed.
	 */
	private ThreadLocalProperties() {
	}
}