Xtend Control Flow

#10 Xtend Control Flow

Aug 20, 2012 | 12 minutes | Beginners, Xtend
Xtend comes with two new cool control flow features: dispatch and switch. Here I show how to use them to improve the coding.
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Xtend Documentation:
- Dispatch: http://www.eclipse.org/xtend/documentation.html#polymorphicDispatch
- Switch: http://www.eclipse.org/xtend/documentation.html#switchExpression

Dispatch implementation:

xtend 
class PrettyPrinterXtend1 {
        public static val DecimalFormat INT_FORMAT = new DecimalFormat("00");

        def public static dispatch String prettyPrint(Integer intValue) {
                return "Integer: " + INT_FORMAT.format(intValue);
        }

        def public static dispatch String prettyPrint(Rectangle it) {
                if (width ==  height) {
                        return "Square with side=" + width;
                }
                        
                "Rect with width=" + width + " and height=" + height;
        }
                
        def public static dispatch String prettyPrint(Void object) {
                "<null>"
        }

        def public static dispatch String prettyPrint(Object object) {
                "Object: " + object;
        }
        
}

Switch implementation:

xtend 
class PrettyPrinterXtend2 {
        public static val DecimalFormat INT_FORMAT = new DecimalFormat("00");

        def public static String prettyPrint(Object object) {
                switch (object) {
                        Integer:
                                "Integer: " + INT_FORMAT.format(object)
                                
                        Rectangle case object.width == object.height:
                                "Square with side=" + object.width

                        Rectangle:
                                "Rect with width=" + object.width + " and height=" + object.height
                        
                        case null:
                                "<null>"
                        
                        default:
                                "Object: " + object
                }
        }        
}