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
listener.preExecute(getId(), event);
			}
		}
	}
	/**
	 * Returns the category for this command.
	 * 
	 * @return The category for this command; never <code>null</code>.
	 * @throws NotDefinedException
	 *             If the handle is not currently defined.
	 */
	public final Category getCategory() throws NotDefinedException {
		if (!isDefined()) {
			throw new NotDefinedException(
					"Cannot get the category from an undefined command"); 
		}
		return category;
	}
	/**
	 * 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(