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
for (int i = 0; i < parameterizations.length; i++) {
			if (i > 0) {
				
				buffer.append(CommandManager.PARAMETER_SEPARATOR_CHAR);
			}
			final Parameterization parameterization = parameterizations[i];
			final String parameterId = parameterization.getParameter().getId();
			final String escapedParameterId = escape(parameterId);
			buffer.append(escapedParameterId);
			final String parameterValue = parameterization.getValue();
			if (parameterValue != null) {
				final String escapedParameterValue = escape(parameterValue);
				buffer.append(CommandManager.ID_VALUE_CHAR);
				buffer.append(escapedParameterValue);
			}
		}
		buffer.append(CommandManager.PARAMETER_END_CHAR);
		return buffer.toString();
	}
	public final String toString() {
		final StringBuffer buffer = new StringBuffer();
		buffer.append("ParameterizedCommand("); 
		buffer.append(command);
		buffer.append(',');
		buffer.append(parameterizations);
		buffer.append(')');
		return buffer.toString();
	}
}