//: interfaces/classprocessor/Apply.java package interfaces.classprocessor; import java.util.*; import static net.mindview.util.Print.*; class Processor { public String name() { return getClass().getSimpleName(); } Object process(Object input) { return input; } } class Upcase extends Processor { @Override String process(Object input) { // Covariant return return ((String)input).toUpperCase(); } } class Downcase extends Processor { @Override String process(Object input) { return ((String)input).toLowerCase(); } } class Splitter extends Processor { @Override String process(Object input) { // The split() argument divides a String into pieces: return Arrays.toString(((String)input).split(" ")); } } public class Apply { public static void process(Processor p, Object s) { print("Using Processor " + p.name()); print(p.process(s)); } public static String s = "Disagreement with beliefs is by definition incorrect"; public static void main(String[] args) { process(new Upcase(), s); process(new Downcase(), s); process(new Splitter(), s); } } /* Output: Using Processor Upcase DISAGREEMENT WITH BELIEFS IS BY DEFINITION INCORRECT Using Processor Downcase disagreement with beliefs is by definition incorrect Using Processor Splitter [Disagreement, with, beliefs, is, by, definition, incorrect] *///:~