bprocessor-commit

[Michael L. <he...@us...>]

Update of /cvsroot/bprocessor/model/src/net/sourceforge/bprocessor/model
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv11616/src/net/sourceforge/bprocessor/model

Added Files:
	Constraint.java 
Log Message:
Added a constraint class

--- NEW FILE: Constraint.java ---
//---------------------------------------------------------------------------------
// $Id: Constraint.java,v 1.1 2006/01/10 10:45:21 henryml Exp $
//
// Copyright (c) 2005      The BProcessor Team (http://bprocessor.sourceforge.net) 
// Released under the Lesser GNU Public License v2.1
//---------------------------------------------------------------------------------

package net.sourceforge.bprocessor.model;

import java.util.Collection;
import java.util.LinkedList;

/**
 * The Constraint has a master and a slave, which are
 * geometric entities.
 * The constraint depends on the both the master and the slave,
 * but only the slave depends on the constraint. 
 * The constraint are not supposed to change the master. A change 
 * to the master will make the constraint change the slave. A
 * change to a slave will make the constraint update it's own internal
 * state.
 */
public abstract class Constraint implements Observer {
  /** The master */
  private Entity master;
  
  /** The slave */
  private Entity slave;
  
  /**
   * Constructor for Constraint.
   */
  public Constraint() {
    super();
  }
  
  /**
   * Constructor for Constraint
   * @param master The master
   * @param slave The slave
   */
  public Constraint(Entity master, Entity slave) {
    this();
    this.master = master;
    this.slave = slave;
  }
  
  /**
   * Set the master
   * @param master The master
   */
  public void setMaster(Entity master) {
    this.master = master;
  }
  
  /**
   * Return the master
   * @return The master
   */
  public Entity getMaster() {
    return master;
  }
  
  /**
   * Set the slave
   * @param slave The slave
   */
  public void setSlave(Entity slave) {
    this.slave = slave;
  }
  
  /**
   * Return the slave
   * @return The slave
   */
  public Entity getSlave() {
    return slave;
  }
  
  /**
   * Return true if this Constraint depends on the entity
   * @param entity The entity
   * @return True of this Constraints depends on the entity
   */
  public boolean depends(Entity entity) {
    return (entity == master) || (entity == slave);
  }
  
  /**
   * Return collection of entities depending on this Constraint
   * @return Collecton of depending entities
   */
  public Collection depending() {
    Collection entities = new LinkedList();
    entities.add(slave);
    return entities;
  }
}