com.exigen.ie.constrainer.impl.IntBoolExpAnd 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.IntBoolExp;
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 expression: (IntBoolExp1 AND IntBoolExp2).
 */
final class IntBoolExpAnd extends IntBoolExpForSubject
{

  private IntBoolExp _exp1, _exp2;

  class ObserverBoolExpAnd extends Observer
  {
    IntBoolExp _exp2;

    public ObserverBoolExpAnd(IntBoolExp exp2)
    {
      _exp2 = exp2;
    }

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

    public void update(Subject subject, EventOfInterest interest)
    throws Failure
    {
      // exp1 is false
      if(interest.isMaxEvent())
      {
        // (exp1 && exp2) is false
        setDomainMax(0);
      }
      // exp1 is true -> (exp1 && exp2) == exp2
      else
      {
        setDomainMin(_exp2.min());
        setDomainMax(_exp2.max());
        _exp2.setMin(_min);
        _exp2.setMax(_max);
      }
    }

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

  }

  public IntBoolExpAnd(IntBoolExp exp1, IntBoolExp exp2)
  {
    super(exp1.constrainer());
    _exp1 = exp1;
    _exp2 = exp2;

    if(constrainer().showInternalNames())
    {
      _name = "("+exp1.name()+"&&"+exp2.name()+")";
    }
    setDomainMinMaxSafe();

    _exp1.attachObserver(new ObserverBoolExpAnd(_exp2));
    _exp2.attachObserver(new ObserverBoolExpAnd(_exp1));
  }

  protected boolean isSubjectTrue()
  {
    return _exp1.isTrue() && _exp2.isTrue();
  }

  protected boolean isSubjectFalse()
  {
    return _exp1.isFalse() || _exp2.isFalse();
  }

  protected void setSubjectTrue() throws Failure
  {
    _exp1.setTrue();
    _exp2.setTrue();
  }

  protected void setSubjectFalse() throws Failure
  {
    if(_exp1.isTrue())
      _exp2.setFalse();
    if(_exp2.isTrue())
      _exp1.setFalse();
  }

} // ~IntBoolExpAnd