paintedobjects.java

一个基于swing的网络白板

package mywb;

import java.io.*;
import java.util.*;

public class PaintedObjects implements Serializable, Cloneable {
  protected Vector paintedObjVector = new Vector ();
  protected Vector objIds = new Vector ();

  public synchronized Object add(Object element) {
    Object id = new Integer(System.identityHashCode(element));
    addElementWithID(id, element);
    return id;
 }

  public synchronized void addElementWithID(Object id, Object element) {
    objIds.addElement (id);
    paintedObjVector.addElement (element);
  }

  public synchronized Object replaceObject(Object oldID, Object element){
    int idx = objIds.indexOf (oldID);
    if (idx >= 0) {
      objIds.removeElementAt (idx);
      paintedObjVector.removeElementAt (idx);
      return add(element);
    } else {
      return null;
    }
  }

  public synchronized boolean replaceOjbWithID(Object oldID, Object id, Object element) {
    int index = objIds.indexOf (oldID);
    if (index >= 0){
      objIds.removeElementAt(index);
      paintedObjVector.removeElementAt(index);
      objIds.addElement(id);
      paintedObjVector.addElement(element);
      return true;
    } else {
      return false;
    }
  }

  public synchronized Object getObjectId (Object element) {
    int idx = paintedObjVector.indexOf (element);
    return (idx >= 0) ? objIds.elementAt (idx) : null;
  }

  public synchronized Enumeration elements() {
    return ((Vector) paintedObjVector.clone ()).elements ();
  }

  public synchronized Object clone () {
    try {
      return super.clone ();
    } catch (CloneNotSupportedException ex) {
      return null;
    }
  }
 public synchronized int size(){
   return paintedObjVector.size();
 }
}