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
return rawText;
		return buffer.toString();
	}
	/**
	 * Generates every possible combination of parameter values for the given
	 * parameters. Parameters values that cannot be initialized are just
	 * ignored. Optional parameters are considered.
	 * 
	 * @param startIndex
	 *            The index in the <code>parameters</code> that we should
	 *            process. This must be a valid index.
	 * @param parameters
	 *            The parameters in to process; must not be <code>null</code>.
	 * @return A collection (<code>Collection</code>) of combinations (<code>List</code>
	 *         of <code>Parameterization</code>).
	 * 
	 */
	private static final Collection expandParameters(final int startIndex,
			final IParameter[] parameters) {
		final boolean noMoreParameters = (startIndex + 1 >= parameters.length);
		final IParameter parameter = parameters[startIndex];
		IParameterValues values = null;
		try {
			values = parameter.getValues();
		} catch (final ParameterValuesException e) {
			if (noMoreParameters) {
				return Collections.EMPTY_LIST;
			}
			return expandParameters(startIndex, parameters);
		}