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
* 
	 * @param command
	 *            The command that is parameterized; must not be
	 *            <code>null</code>.
	 * @param parameterizations
	 *            An array of parameterizations binding parameters to values for
	 *            the command. This value may be <code>null</code>. This
	 *            argument is not copied; if you need to make changes to it
	 *            after constructing this parameterized command, then make a
	 *            copy yourself.
	 */
	public ParameterizedCommand(final Command command,
			final Parameterization[] parameterizations) {
		if (command == null) {
			throw new NullPointerException(
					"A parameterized command cannot have a null command"); 
		}
		this.command = command;
		this.parameterizations = (parameterizations == null || parameterizations.length == 0) ? null
				: parameterizations;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see java.lang.Comparable#compareTo(java.lang.Object)
	 */
	public final int compareTo(final Object object) {
		final ParameterizedCommand command = (ParameterizedCommand) object;
		final boolean thisDefined = this.command.isDefined();
		final boolean otherDefined = command.command.isDefined();