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/ExecutionEvent.java
private final Object trigger;
	/**
	 * Constructs a new instance of <code>ExecutionEvent</code> with no
	 * parameters, no trigger and no application context. This is just a
	 * convenience method.
	 * 
	 * @since 3.2
	 */
	public ExecutionEvent() {
		this(Collections.EMPTY_MAP, null, null);
	}
	/**
	 * Constructs a new instance of <code>ExecutionEvent</code>.
	 * 
	 * @param parameters
	 *            The parameters to qualify the execution; must not be
	 *            <code>null</code>. This must be a map of parameter ids (<code>String</code>)
	 *            to parameter values (<code>String</code>).
	 * @param trigger
	 *            The object that triggered the execution; may be
	 *            <code>null</code>.
	 * @param applicationContext
	 *            The state of the application at the time the execution was
	 *            triggered; may be <code>null</code>.
	 */
	public ExecutionEvent(final Map parameters, final Object trigger,
			final Object applicationContext) {
		if (parameters == null) {
			throw new NullPointerException(
					"An execution event must have a non-null map of parameters");