/*
 * FindBugs - Find bugs in Java programs
 * Copyright (C) 2004-2006 University of Maryland
 * 
 * This library 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 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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 copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package edu.umd.cs.findbugs;
import java.util.Map;

import edu.umd.cs.findbugs.classfile.Global;

public class AnalysisLocal<T> {
	protected T initialValue() {
		return null;
	}

	@SuppressWarnings("unchecked")
    protected Map <AnalysisLocal<T>, T> getMap() {
		Map<?,?> m = Global.getAnalysisCache().getAnalysisLocals();
		return (Map<AnalysisLocal<T>, T>) m;
	}

	public T get() {
		Map<AnalysisLocal<T>, T> m = getMap();

		if (m.containsKey(this)) {
			return m.get(this);
		}

		synchronized(m) {
			if (m.containsKey(this)) {
				return m.get(this);
			}
			T result = initialValue();
			m.put(this,result);
			return result;
		}
	}
	public  void set(T value) {
		Map<AnalysisLocal<T>, T> m = getMap();
		m.put(this, value);
	}
	public  void  remove() {
		Map<AnalysisLocal<T>, T> m = getMap();
		m.remove(this);
	}
}
