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/CommandManager.java
category.addCategoryListener(this);
		}
		return category;
	}
	/**
	 * Gets the command with the given identifier. If no such command currently
	 * exists, then the command will be created (but will be undefined).
	 * 
	 * @param commandId
	 *            The identifier to find; must not be <code>null</code> and
	 *            must not be zero-length.
	 * @return The command with the given identifier; this value will never be
	 *         <code>null</code>, but it might be undefined.
	 * @see Command
	 */
	public final Command getCommand(final String commandId) {
		checkId(commandId);
		Command command = (Command) handleObjectsById.get(commandId);
		if (command == null) {
			command = new Command(commandId);
			handleObjectsById.put(commandId, command);
			command.addCommandListener(this);
			if (executionListener != null) {
				command.addExecutionListener(executionListener);
			}
		}
		return command;
	}
	/**
	 * Returns the those categories that are defined.