com.exigen.ie.constrainer.impl.IntExpDivExp Maven / Gradle / Ivy

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package com.exigen.ie.constrainer.impl;

import com.exigen.ie.constrainer.EventOfInterest;
import com.exigen.ie.constrainer.Failure;
import com.exigen.ie.constrainer.IntExp;
import com.exigen.ie.constrainer.IntVar;
import com.exigen.ie.constrainer.Observer;
import com.exigen.ie.constrainer.Subject;

/**
 * Title: 
 * Description: 
 * Copyright: Copyright (c) 2002
 * Company: 
 * @author unascribed
 * @version 1.0
 */

public class IntExpDivExp extends IntExpImpl
{
  private IntExp _numerator, _denominator;
  private Observer _observer;
  private IntVar _quotient;

  public IntExpDivExp(IntExp numerator, IntExp denominator){
    super(numerator.constrainer());
    _numerator = numerator;
    _denominator = denominator;

    if(constrainer().showInternalNames())
    {
      _name = "("+_numerator.name()+"/"+_denominator.name()+")";
    }

    _observer = new IntExpDivExpObserver();
    _numerator.attachObserver(_observer);
    _denominator.attachObserver(_observer);

     int trace = 0;
    _quotient = constrainer ().addIntVarTraceInternal (
      calc_min(), calc_max() , "div", IntVar.DOMAIN_PLAIN, trace
    );

  }

  private int calc_min(){
    int min1 = _numerator.min();
    int max1 = _numerator.max();
    int min2 = _denominator.min();
    int max2 = _denominator.max();
    if (max2>0 && min2<0)
      return -Math.max(Math.abs(min1), Math.abs(min2));
    return Math.min(Math.min(min1/min2, min1/max2), Math.min(max1/min2, max1/max2));
  }

  private int calc_max(){
    int min1 = _numerator.min();
    int max1 = _numerator.max();
    int min2 = _denominator.min();
    int max2 = _denominator.max();
    if (max2>0 && min2<0)
      return Math.max(Math.abs(min1), Math.abs(min2));
    return Math.max(Math.max(min1/min2, min1/max2), Math.max(max1/min2, max1/max2));
  }

  public int min(){
    return _quotient.min();
  }

  public int max(){
    return _quotient.max();
  }

  public void setMin(int min) throws Failure{
    if (min <= min())
      return;

    _quotient.setMin(min);

    int dmin = _denominator.min();
    int dmax = _denominator.max();
    int remainder = Math.max(Math.abs(dmin), Math.abs(dmax)) - 1;

    int nmin = IntCalc.productMin(min, max(), dmin, dmax);
    _numerator.setMin(nmin-remainder);

    int nmax = IntCalc.productMax(min, max(), dmin, dmax);
    _numerator.setMax(nmax+remainder);
  }

  public void setMax(int max) throws Failure{
    if (max >= max())
      return;

    _quotient.setMax(max);

    int dmin = _denominator.min();
    int dmax = _denominator.max();
    int remainder = Math.max(Math.abs(dmin), Math.abs(dmax)) - 1;

    int nmin = IntCalc.productMin(max, min(), dmin, dmax);
    _numerator.setMin(nmin-remainder);

    int nmax = IntCalc.productMax(max, min(), dmin, dmax);
    _numerator.setMax(nmax+remainder);
  }

  public void name(String name)
  {
    super.name(name);
    _quotient.name(name);
  }

  public void attachObserver(Observer observer)
  {
    super.attachObserver(observer);
    _quotient.attachObserver(observer);
  }

  public void reattachObserver(Observer observer)
  {
    super.reattachObserver(observer);
    _quotient.reattachObserver(observer);
  }

  public void detachObserver(Observer observer)
  {
    super.detachObserver(observer);
    _quotient.detachObserver(observer);
  }

  public void setValue(int val) throws Failure {
    setMin(val);
    setMax(val);
  }

  class IntExpDivExpObserver extends Observer
  {

    public void update(Subject subject, EventOfInterest event)
    throws Failure
    {
      if ((_denominator.min() == 0) || (_denominator.max() == 0))
        _denominator.removeValue(0);
      _quotient.setMin(calc_min());
      _quotient.setMax(calc_max());
    }

    public String toString()
    {
      return "IntExpMulExpObserver: " + _numerator + " x " + _denominator;
    }

    public Object master()
    {
      return IntExpDivExp.this;
    }

    public int subscriberMask()
    {
      return MIN | MAX | VALUE;
    }

  } //~ IntExpMulExpObserver



}