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
commandIdEscaped = serializedParameterizedCommand;
			serializedParameters = null;
		} else {
			commandIdEscaped = serializedParameterizedCommand.substring(0,
					lparenPosition);
			if (serializedParameterizedCommand
					.charAt(serializedParameterizedCommand.length() - 1) != PARAMETER_END_CHAR) {
				throw new SerializationException(
						"Parentheses must be balanced in serialized ParameterizedCommand"); 
			}
			serializedParameters = serializedParameterizedCommand.substring(
					lparenPosition + 1, 
					serializedParameterizedCommand.length() - 1); 
			
		}
		final String commandId = unescape(commandIdEscaped);
		final Command command = getCommand(commandId);
		final IParameter[] parameters = command.getParameters();
		final Parameterization[] parameterizations = getParameterizations(
				serializedParameters, parameters);
		return new ParameterizedCommand(command, parameterizations);
	}
	/**
	 * Notifies all of the listeners to this manager that the set of defined
	 * command identifiers has changed.
	 * 
	 * @param event
	 *            The event to send to all of the listeners; must not be
	 *            <code>null</code>.
	 */