undefinedvalue.java

UML设计测试工具

/*
 * USE - UML based specification environment
 * Copyright (C) 1999-2004 Mark Richters, University of Bremen
 *
 * This program 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 2 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
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/* $ProjectHeader: use 2-3-0-release.1 Mon, 12 Sep 2005 20:18:33 +0200 green $ */

package org.tzi.use.uml.ocl.value;

import org.tzi.use.uml.ocl.type.Type;

/**
 * The undefined value.
 *
 * @version     $ProjectVersion: 2-3-0-release.1 $
 * @author  Mark Richters
 */
public final class UndefinedValue extends Value implements Comparable {
    
    public UndefinedValue(Type type) {
        super(type);
    }

    public String toString() {
        return "Undefined";
    }

    public boolean equals(Object obj) {
        if (obj == this )
            return true;
        else if (obj instanceof UndefinedValue )
            return ((UndefinedValue) obj).type().equals(type());
        return false;
    }

    public int hashCode() {
        return type().hashCode();
    }

    public int compareTo(Object o) {
        if (o == this )
            return 0;
        // may compare to any value
        if (! (o instanceof Value) )
            throw new ClassCastException();
        if (o instanceof UndefinedValue )
            return 0;
        return -1;
    }
}