How to decide if an object was completely encoded using XMLEncoder

Question

Hi, 'completely encoded' means that the object reconstructed from XMLDecoder is equal to the original object. Here is an example class which is not 'completely encoded' (because one of its properties is of type java.awt.geom.Point2D):
public static class SomeBean {
  private Dimension size;
  private Point2D location;
  public Dimension getSize() {
    return size;
  public void setSize(Dimension size) {
    this.size = size;
  public Point2D getLocation() {
    return location;
  public void setLocation(Point2D point) {
    this.location = point;
  public String toString() {
    return getClass().getName() + "[location=" + location +
      ",size=" + size + "]";
here is the corresponding XML representation:
<?xml version="1.0" encoding="UTF-8"?>
<java version="1.5.0_12" class="java.beans.XMLDecoder">
  <object class="XML_Persistence$SomeBean">
    <void property="location">
      <object class="java.awt.geom.Point2D$Float"/>
    </void>
    <void property="size">
      <object class="java.awt.Dimension">
        <int>42</int>
        <int>42</int>
      </object>
    </void>
  </object>
</java>
By printing out the two objects, you can see that they are not equal:
Serializing: XML_Persistence$SomeBean[location=Point2D.Float[42.0, 42.0],size=java.awt.Dimension[width=42,height=42]]
Deserialzed: XML_Persistence$SomeBean[location=Point2D.Float[0.0, 0.0],size=java.awt.Dimension[width=42,height=42]]
It isn't problematic for my app if an object cannot be 'completely encoded', i'm just looking for a reliable way to know.
Thanks, Hans

Answer 1

ejp wrote:
This is very odd. The XMLEncoder already does a trial decode to make sure it has serialized the object.
Doesn't a line like this one
<object class="java.awt.geom.Point2D$Float"/>
indicate that an object (as part of an object graph) was encoded without any additional information?Exactly. But the XMLEncoder assumes wevertying is a Java bean, with getters and setters. Any object without set methods isn't going to be serialized correctly. You need to add your own PersistenceDelegate for any such classes you find.Thanks, ejp - knowing that an object cannot be reconstructed by encoding/decoding it would be sufficient. Currently my strategy is:
a) Encode the object to memory, using XMLEncoder.
b) If no exceptions were thrown, parse the resulting XML for lines of the form "<object ... />". If any such line is found, the object is no candidate for XML-serialization.
c) If the object (or a super-class) overrides Object.equals, the XML is decoded and the resulting object is compared to the original one.