Bug 267021 [DataBinding] NotUsedLocally errors in org.eclipse.core.databinding
bundles/org.eclipse.core.databinding.property/src/org/eclipse/core/databinding/property/set/DelegatingSetProperty.java
* @return the property to delegate to for the specified source object.
	 */
	protected final ISetProperty getDelegate(Object source) {
		if (source == null)
			return nullProperty;
		ISetProperty delegate = doGetDelegate(source);
		if (delegate == null)
			delegate = nullProperty;
		return delegate;
	}
	/**
	 * Returns the property to delegate to for the specified source object.
	 * Implementers must ensure that repeated calls to this method with the same
	 * source object returns the same delegate instance.
	 * 
	 * @param source
	 *            the property source
	 * @return the property to delegate to for the specified source object.
	 */
	protected abstract ISetProperty doGetDelegate(Object source);
	public Object getElementType() {
		return elementType;
	}
	public IObservableSet observe(Object source) {
		return getDelegate(source).observe(source);
	}
	public IObservableSet observe(Realm realm, Object source) {
		return getDelegate(source).observe(realm, source);
	}
	private class NullSetProperty extends SimpleSetProperty {