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/ParameterizedCommand.java
* the included and not included cases are considered.
	 * </p>
	 * <p>
	 * If one of the parameters cannot be loaded due to a
	 * <code>ParameterValuesException</code>, then it is simply ignored.
	 * </p>
	 * 
	 * @param command
	 *            The command for which the parameter combinations should be
	 *            generated; must not be <code>null</code>.
	 * @return A collection of <code>ParameterizedCommand</code> instances
	 *         representing all of the possible combinations. This value is
	 *         never empty and it is never <code>null</code>.
	 * @throws NotDefinedException
	 *             If the command is not defined.
	 */
	public static final Collection generateCombinations(final Command command)
			throws NotDefinedException {
		final IParameter[] parameters = command.getParameters();
		if (parameters == null) {
			return Collections
					.singleton(new ParameterizedCommand(command, null));
		}
		final Collection expansion = expandParameters(0, parameters);
		final Collection combinations = new ArrayList(expansion.size());
		final Iterator expansionItr = expansion.iterator();
		while (expansionItr.hasNext()) {
			final List combination = (List) expansionItr.next();
			while (combination.remove(null)) {