Bug 127861 [DataBinding] Mark API provisional
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/databinding/updatables/WritableSet.java
Assert.isTrue(!isDisposed());
		
		data.clear();
	}
	/**
	 * Adds the given element to the set. Has no effect if the set already contains the element.
	 * 
	 * @param toAdd element to add
	 */
	public void add(Object toAdd) {
		addAll(Collections.singleton(toAdd));
	}
	
	/**
	 * Removes the given element from the set. Has no effect if the set does not contain the
	 * element
	 * 
	 * @param toRemove element to remove
	 */
	public void remove(Object toRemove) {
		removeAll(Collections.singleton(toRemove));
	}
	
	/**
	 * Adds the given elements to the reciever. Elements already contained in the reciever are ignored.
	 * 
	 * @param toAdd elements to add
	 */
	public void addAll(Collection toAdd) {
		Assert.isTrue(!isDisposed());