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/ParameterizedCommand.java
}
			if (combination.isEmpty()) {
				combinations.add(new ParameterizedCommand(command, null));
			} else {
				final Parameterization[] parameterizations = (Parameterization[]) combination
						.toArray(new Parameterization[combination.size()]);
				combinations.add(new ParameterizedCommand(command,
						parameterizations));
			}
		}
		return combinations;
	}
	/**
	 * The base command which is being parameterized. This value is never
	 * <code>null</code>.
	 */
	private final Command command;
	/**
	 * The hash code for this object. This value is computed lazily, and marked
	 * as invalid when one of the values on which it is based changes.
	 */
	private transient int hashCode = HASH_CODE_NOT_COMPUTED;
	/**
	 * This is an array of parameterization defined for this command. This value
	 * may be <code>null</code> if the command has no parameters.
	 */
	private final Parameterization[] parameterizations;
	/**
	 * Constructs a new instance of <code>ParameterizedCommand</code> with
	 * specific values for zero or more of its parameters.