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
}
	/**
	 * Returns the parameters for this command. This call triggers provides a
	 * copy of the array, so excessive calls to this method should be avoided.
	 * 
	 * @return The parameters for this command. This value might be
	 *         <code>null</code>, if the command has no parameters.
	 * @throws NotDefinedException
	 *             If the handle is not currently defined.
	 */
	public final IParameter[] getParameters() throws NotDefinedException {
		if (!isDefined()) {
			throw new NotDefinedException(
					"Cannot get the parameters from an undefined command"); 
		}
		if ((parameters == null) || (parameters.length == 0)) {
			return null;
		}
		final IParameter[] returnValue = new IParameter[parameters.length];
		System.arraycopy(parameters, 0, returnValue, 0, parameters.length);
		return returnValue;
	}
	/**
	 * Returns the {@link ParameterType} for the parameter with the provided id
	 * or <code>null</code> if this command does not have a parameter type
	 * with the id.
	 * 
	 * @param parameterId
	 *            The id of the parameter to retrieve the {@link ParameterType}
	 *            of.