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/CommandManagerEvent.java
* Returns whether the category identifier became defined. Otherwise, the
	 * category identifier became undefined.
	 * 
	 * @return <code>true</code> if the category identifier became defined;
	 *         <code>false</code> if the category identifier became undefined.
	 */
	public final boolean isCategoryDefined() {
		return (((changedValues & CHANGED_CATEGORY_DEFINED) != 0) && (categoryId != null));
	}
	/**
	 * Returns whether the list of defined command identifiers has changed.
	 * 
	 * @return <code>true</code> if the list of command identifiers has
	 *         changed; <code>false</code> otherwise.
	 */
	public final boolean isCommandChanged() {
		return (commandId != null);
	}
	/**
	 * Returns whether the command identifier became defined. Otherwise, the
	 * command identifier became undefined.
	 * 
	 * @return <code>true</code> if the command identifier became defined;
	 *         <code>false</code> if the command identifier became undefined.
	 */
	public final boolean isCommandDefined() {
		return (((changedValues & CHANGED_COMMAND_DEFINED) != 0) && (commandId != null));
	}
}