/** A constant InequalityTerm.

 Copyright (c) 1997-2005 The Regents of the University of California.
 All rights reserved.
 Permission is hereby granted, without written agreement and without
 license or royalty fees, to use, copy, modify, and distribute this
 software and its documentation for any purpose, provided that the above
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 IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
 FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
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 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
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 PT_COPYRIGHT_VERSION_2
 COPYRIGHTENDKEY

 */
package ptolemy.graph.test;

import ptolemy.graph.GraphActionException;
import ptolemy.graph.InequalityTerm;

//////////////////////////////////////////////////////////////////////////
//// TestConstant

/**
 A constant InequalityTerm.
 This class is for testing inequality related classes.
 The value of this InequalityTerm is a String set in the constructor.
 This term has name, which is used for printing test result.

 @author Yuhong Xiong
 @version $Id$
 @since Ptolemy II 0.2
 @Pt.ProposedRating Red (cxh)
 @Pt.AcceptedRating Red (cxh)
 */
public class TestConstant implements InequalityTerm {
    /** Construct a constant InequalityTerm with a String value.
     *  @param value A String
     */
    public TestConstant(String value) {
        _value = value;
    }

    ///////////////////////////////////////////////////////////////////
    ////                         public methods                    ////

    /** Do nothing.
     */
    public void fixValue() {
    }

    /** Return the string value.
     *  @return A String
     */
    public Object getAssociatedObject() {
        return _value;
    }

    /** Return the information of this term. The information is a
     *  String of the form: <name>(constant)_<value>
     *  @return A String
     */
    public String getInfo() {
        return _name + "(constant)_" + getValue();
    }

    /** Return the constant String value of this term.
     *  @return a String
     */
    public Object getValue() {
        return _value;
    }

    /** Return an array of size zero.
     *  @return an array of InequalityTerms
     */
    public InequalityTerm[] getVariables() {
        return new InequalityTerm[0];
    }

    /** Return false.
     *  @return false
     */
    public boolean isSettable() {
        return false;
    }

    /** Throw an Exception.
     *  @exception GraphActionException Always thrown since this term is a
     *   constant.
     */
    public void initialize(Object e) throws GraphActionException {
        throw new GraphActionException("TestConstant.initialize: This term "
                + "is a constant.");
    }

    /** Check whether the current value of this term is acceptable,
     *  and return true if it is.  In this class, a value is always
     *  acceptable.
     *  @return True.
     */
    public boolean isValueAcceptable() {
        return true;
    }

    /** Set the name of this constant. If the specified String is null,
     *  Set the name to an empty String.
     *  @param A String
     */
    public void setName(String name) {
        if (name != null) {
            _name = name;
        } else {
            _name = "";
        }
    }

    /** Throw an Exception.
     *  @param e an Object. Ignored by this method.
     *  @exception GraphActionException always thrown.
     */
    public void setValue(Object e) throws GraphActionException {
        throw new GraphActionException("TestConstant.setValue: This term "
                + "is a constant.");
    }

    /** Override the base class to describe the constant.
     *  @return A string describing the constant
     */
    public String toString() {
        return getClass().getName() + getInfo();
    }

    /** Do nothing.
     */
    public void unfixValue() {
    }

    ///////////////////////////////////////////////////////////////////
    ////                         private methods                   ////
    private String _name = "";

    private String _value = null;
}