Implementation of type facet and type decorator.

A Design Pattern for Type Extension With Facets and Decorators
by Chung-Yeung Pang
Listing 1. Implementation of type facet and type decorator.

package Type_Extension;
public class ExtensibleObject {
    public String objName = null;
    public java.util.Hashtable decorator = null;

    public ExtensibleObject() {}
    public void setName(String _name) {
        objName = _name;

public class TypeFacet {
    public ExtensibleObject me;
    public TypeFacet(ExtensibleObject exObj) {
       me = exObj;

public class TypeDecorator extends
  ExtensibleObject {
    public ExtensibleObject me;

    public TypeDecorator() {
    public void decorate(ExtensibleObject myObj) {
       me = myObj;
       if (myObj.decorator == null)
           myObj.decorator =
             new java.util.Hashtable();
              if (name == null)
                      name = this.getClass().getName();
       myObj.decorator.put(name, this);


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