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/CommandManager.java
final ExecutionEvent event) {
			if (executionListeners != null) {
				final Object[] listeners = executionListeners.getListeners();
				for (int i = 0; i < listeners.length; i++) {
					final Object object = listeners[i];
					if (object instanceof IExecutionListener) {
						final IExecutionListener listener = (IExecutionListener) object;
						listener.preExecute(commandId, event);
					}
				}
			}
		}
	}
	/**
	 * The identifier of the category in which all auto-generated commands will
	 * appear. This value must never be <code>null</code>.
	 */
	public static final String AUTOGENERATED_CATEGORY_ID = "org.eclipse.core.commands.categories.autogenerated"; 
	/**
	 * The escape character to use for serialization and deserialization of
	 * parameterized commands.
	 */
	static final char ESCAPE_CHAR = '%';
	/**
	 * The character that separates a parameter id from its value.
	 */
	static final char ID_VALUE_CHAR = '=';
	/**
	 * The character that indicates the end of a list of parameters.
	 */