VoidValue.java

/*******************************************************************************
 *
 *	Copyright (C) 2008 Fujitsu Services Ltd.
 *
 *	Author: Nick Battle
 *
 *	This file is part of VDMJ.
 *
 *	VDMJ is free software: you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License as published by
 *	the Free Software Foundation, either version 3 of the License, or
 *	(at your option) any later version.
 *
 *	VDMJ 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 General Public License for more details.
 *
 *	You should have received a copy of the GNU General Public License
 *	along with VDMJ.  If not, see <http://www.gnu.org/licenses/>.
 *
 ******************************************************************************/

package org.overture.interpreter.values;

import java.util.Set;

import org.overture.ast.analysis.AnalysisException;
import org.overture.ast.types.AVoidType;
import org.overture.ast.types.PType;
import org.overture.interpreter.runtime.Context;

public class VoidValue extends Value
{
	private static final long serialVersionUID = 1L;

	@Override
	public String toString()
	{
		return "()";
	}

	@Override
	public boolean equals(Object other)
	{
		if (other instanceof Value)
		{
			Value val = ((Value) other).deref();
			return val instanceof VoidValue;
		}

		return false;
	}

	@Override
	public boolean isVoid()
	{
		return true;
	}

	@Override
	public int hashCode()
	{
		return 0;
	}

	@Override
	public String kind()
	{
		return toString();
	}

	@Override
	protected Value convertValueTo(PType to, Context ctxt, Set<PType> done)
			throws AnalysisException
	{
		if (ctxt.assistantFactory.createPTypeAssistant().isType(to, AVoidType.class))
		{
			return new VoidValue();
		} else
		{
			return super.convertValueTo(to, ctxt, done);
		}
	}

	@Override
	public Object clone()
	{
		return new VoidValue();
	}
}