Bug 126414 [Commands] handlers: Provide help context ids
For commands and handlers to replace actions, they need to be capable of providing help context identifiers. For an example, see OpenResourceHandler in org.eclipse.ui.ide. This help context id will need to be definable through XML and through code.
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/Command.java
if (executionListeners.isEmpty()) {
				executionListeners = null;
			}
		}
	}
	/**
	 * <p>
	 * Removes a state from this command. This will remove the state from the
	 * active handler, if the active handler is an instance of
	 * {@link IObjectWithState}.
	 * </p>
	 * 
	 * @param stateId
	 *            The identifier of the state to remove; must not be
	 *            <code>null</code>.
	 */
	public void removeState(final String stateId) {
		if (handler instanceof IObjectWithState) {
			((IObjectWithState) handler).removeState(stateId);
		}
		super.removeState(stateId);
	}
	/**
	 * Changes the handler for this command. This will remove all the state from
	 * the currently active handler (if any), and add it to <code>handler</code>.
	 * If debugging is turned on, then this will also print information about
	 * the change to <code>System.out</code>.
	 * 
	 * @param handler
	 *            The new handler; may be <code>null</code> if none.