package com.exigen.ie.constrainer.impl;
import com.exigen.ie.constrainer.Constraint;
import com.exigen.ie.constrainer.ConstraintImpl;
import com.exigen.ie.constrainer.EventOfInterest;
import com.exigen.ie.constrainer.ExpressionFactory;
import com.exigen.ie.constrainer.Failure;
import com.exigen.ie.constrainer.Goal;
import com.exigen.ie.constrainer.IntBoolExp;
import com.exigen.ie.constrainer.IntExp;
import com.exigen.ie.constrainer.Observer;
import com.exigen.ie.constrainer.Subject;
///////////////////////////////////////////////////////////////////////////////
/*
* Copyright Exigen Group 1998, 1999, 2000
* 320 Amboy Ave., Metuchen, NJ, 08840, USA, www.exigengroup.com
*
* The copyright to the computer program(s) herein
* is the property of Exigen Group, USA. All rights reserved.
* The program(s) may be used and/or copied only with
* the written permission of Exigen Group
* or in accordance with the terms and conditions
* stipulated in the agreement/contract under which
* the program(s) have been supplied.
*/
///////////////////////////////////////////////////////////////////////////////
/**
* An implementation of the constraint: <code>IntExp == value</code>.
*/
public final class ConstraintExpEqualsValue extends ConstraintImpl
{
// PRIVATE MEMBERS
private IntExp _exp;
private int _value;
private Constraint _opposite;
public ConstraintExpEqualsValue(IntExp exp, int value)
{
super(exp.constrainer());
if(constrainer().showInternalNames())
{
_name = "("+exp.name()+"=="+value+")";
}
_exp = exp;
_value = value;
}
public Goal execute() throws Failure
{
class ObserverEqualValue extends Observer
{
public void update(Subject exp, EventOfInterest interest) throws Failure
{
//Debug.on();Debug.print("ObserverEqualValue: "+interest);Debug.off();
IntEvent event = (IntEvent)interest;
if ( (event.isValueEvent() && event.min() != _value) ||
(event.isMaxEvent() && event.max() < _value) ||
(event.isMinEvent() && event.min() > _value))
{
exp.constrainer().fail("from ObserverEqualValue");
}
_exp.setValue(_value);
}
public int subscriberMask()
{
return EventOfInterest.VALUE | EventOfInterest.MIN | EventOfInterest.MAX;
}
public String toString()
{
return "ObserverEqualValue";
}
public Object master()
{
return ConstraintExpEqualsValue.this;
}
} //~ ObserverEqualValue
_exp.setValue(_value); // may fail
_exp.attachObserver(new ObserverEqualValue());
return null;
}
public Constraint opposite()
{
if (_opposite == null)
_opposite = new ConstraintExpNotValue(_exp,_value);
return _opposite;
}
public boolean isLinear(){
return _exp.isLinear();
}
public IntBoolExp toIntBoolExp(){
ExpressionFactory factory = constrainer().expressionFactory();
Class clazz = IntBoolExpEqValue.class;
Object[] args = new Object[]{_exp, new Integer(_value)};
Class[] types = new Class[]{IntExp.class, int.class};
return (IntBoolExpEqValue) factory.getExpression(clazz, args, types);
}
public String toString()
{
return _exp+"="+_value;
}
} //~ ConstraintExpEqualsValue