constrainthelper.java

Java 3D Desktop Environment旨在使用Java 3D来创建一个3D桌面环境。功能包括：分布式的应用程序

package org.j3de.ui.constraint;

import java.util.Enumeration;
import java.util.Vector;

import org.j3de.exception.ExceptionHandler;    
import org.j3de.ui.LayoutConstraint;
import org.j3de.ui.Skin;
import org.j3de.ui.Skinable;
import org.j3de.ui.SkinException;

public class ConstraintHelper implements HasConstraints, Skinable {
  private Vector constraintListeners;
  private Vector constraints;
  private Vector constraintData;
  private Skin   skin;

  public ConstraintHelper() {
    constraintListeners = new Vector();
    constraints         = new Vector();
    constraintData      = new Vector();
  }

  public void setSkin(Skin skin) { 
    this.skin = skin;
    
    // LayoutConstraints are Skin dependend ... remove all old Constraints 
    while (constraints.size() > 0)
      removeConstraint((LayoutConstraint)constraints.get(0));

    // Add LayoutzConstraints from new Skin
    ConstraintData data;
    for (int i=0; i<constraintData.size(); i++) {
      data = (ConstraintData)constraintData.get(i);
      try {
        addConstraint(skin.getLayoutConstraint(data.constraintClass, data.param));
      } catch (SkinException e) {
        ExceptionHandler.handleException(e);
      }
    }
  }

  public Enumeration getConstraints() {
    return constraints.elements();
  }

  public void addConstraintListener(ConstraintListener listener) {
    constraintListeners.add(listener);
  }

  public void removeConstraintListener(ConstraintListener listener) {
    constraintListeners.remove(listener);  
  }

  public void addConstraint(Class constraintClass, ConstraintParam param) {
    constraintData.add(new ConstraintData(constraintClass, param));
    try {
      LayoutConstraint constraint = skin.getLayoutConstraint(constraintClass, param);
      addConstraint(constraint);
    } catch (SkinException e) {
      ExceptionHandler.handleException(e);
    }
  }

  private void addConstraint(LayoutConstraint constraint) {
    constraints.add(constraint);
    for (int i=0; i<constraintListeners.size(); i++)
      ((ConstraintListener)constraintListeners.get(i)).addConstraint(constraint);
  }

  private void removeConstraint(LayoutConstraint constraint) {
    constraints.remove(constraint);
    for (int i=0; i<constraintListeners.size(); i++)
      ((ConstraintListener)constraintListeners.get(i)).removeConstraint(constraint);
  }

  private class ConstraintData {
    public ConstraintParam param;
    public Class           constraintClass;
    
    public ConstraintData(Class constraintClass, ConstraintParam param) {
      this.constraintClass = constraintClass;
      this.param = param;
    }
  }
}