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
* category id, then the category has become undefined.
	 */
	private static final int CHANGED_CATEGORY_DEFINED = 1;
	/**
     * The bit used to represent whether the given command has become defined.
     * If this bit is not set and there is no command id, then no command has
     * become defined nor undefined. If this bit is not set and there is a
     * command id, then the command has become undefined.
     */
	private static final int CHANGED_COMMAND_DEFINED = 1 << 1;
	/**
	 * The category identifier that was added or removed from the list of
	 * defined category identifiers. This value is <code>null</code> if the
	 * list of defined category identifiers did not change.
	 */
	private final String categoryId;
	/**
	 * A collection of bits representing whether certain values have changed. A
	 * bit is set (i.e., <code>1</code>) if the corresponding property has
	 * changed.
	 */
	private final int changedValues;
	/**
	 * The command identifier that was added or removed from the list of defined
	 * command identifiers. This value is <code>null</code> if the list of
	 * defined command identifiers did not change.
	 */
	private final String commandId;
	/**
	 * The command manager that has changed.