Bug 121709 [Commands] parameters: Add types
I'm going to attach a patch that adds support for typed command parameters. This addresses several issues: - parameter values are strings, but handlers may want to work on objects - multiple handlers of a command should have a consistent way of converting string parameter values to objects - tooling to construct parameterized commands that starts with object parameter values needs a way of producing string parameter values that will work when the command is executed - there should be a way to classify commands by their object parameter types so, given an object, a set of commands that may work with it can be suggested To address these issues, the patch allows parameter types to be declared in the extension-point XML. The example below defines a command for negating integers and a parameter type that works with it. <extension point="org.eclipse.ui.commands"> <command id="org.example.commands.negateInteger" defaultHandler="org.example.commands.NegateIntegerHandler" name="Negate an Integer"> <commandParameter id="param" name="the param" optional="false" typeId="org.example.commands.Integer"/> </command> <commandParameterType id="org.example.commands.Integer" converter="org.example.commands.IntegerConverter" type="java.lang.Integer"/> </extension> In addition to extending the schema for org.eclipse.ui.commands, code has been added to a number of plugins (primarily org.eclipse.core.commands) to support the notion of typed parameters.
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/Command.java
executionListeners = new ListenerList(ListenerList.IDENTITY);
		}
		executionListeners.add(executionListener);
	}
	/**
	 * <p>
	 * Adds a state to this command. This will add this state to the active
	 * handler, if the active handler is an instance of {@link IObjectWithState}.
	 * </p>
	 * 
	 * @param id
	 *            The identifier of the state to add; must not be
	 *            <code>null</code>.
	 * @param state
	 *            The state to add; must not be <code>null</code>.
	 */
	public void addState(final String id, final IState state) {
		super.addState(id, state);
		if (handler instanceof IObjectWithState) {
			((IObjectWithState) handler).addState(id, state);
		}
	}
	/**
	 * Compares this command with another command by comparing each of its
	 * non-transient attributes.
	 * 
	 * @param object
	 *            The object with which to compare; must be an instance of
	 *            <code>Command</code>.
	 * @return A negative integer, zero or a postivie integer, if the object is