Bug 89031 [Undo/Redo] IWorkbench#getOperationSupport() marked experimental
IWorkbench#getOperationSupport() marked experimental
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/DefaultOperationHistory.java
/**
	 * the list of {@link IOperationHistoryListener}s
	 */
	protected List listeners = new ArrayList();
	/**
	 * the list of operations available for redo, LIFO
	 */
	private List redoList = new ArrayList();
	/**
	 * the list of operations available for undo, LIFO
	 */
	private List undoList = new ArrayList();
	
	/**
	 * An operation that is "absorbing" all other operations while
	 * it is open.  When this is not null, other operations added or
	 * executed are added to this composite. 
	 * 
	 */
	private ICompositeOperation openComposite = null;
	
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.commands.operations.IOperationHistory#add(org.eclipse.core.commands.operations.IUndoableOperation)
	 */
	public void add(IUndoableOperation operation) {
		Assert.isNotNull(operation);
		
		/*