OnJava8-Examples/interfaces/interfaceprocessor/StringProcessor.java

// interfaces/interfaceprocessor/StringProcessor.java
// <20>2016 MindView LLC: see Copyright.txt
package interfaces.interfaceprocessor;
import java.util.*;

public abstract class StringProcessor implements Processor{
  @Override
  public String name() {
    return getClass().getSimpleName();
  }
  @Override
  public abstract String process(Object input);
  public static String s =
    "If she weighs the same as a duck, she's made of wood";
  public static void main(String[] args) {
    Apply.process(new Upcase(), s);
    Apply.process(new Downcase(), s);
    Apply.process(new Splitter(), s);
  }
}

class Upcase extends StringProcessor {
  @Override
  public String process(Object input) { // Covariant return
    return ((String)input).toUpperCase();
  }
}

class Downcase extends StringProcessor {
  @Override
  public String process(Object input) {
    return ((String)input).toLowerCase();
  }
}

class Splitter extends StringProcessor {
  @Override
  public String process(Object input) {
    return Arrays.toString(((String)input).split(" "));
  }
}
/* Output:
Using Processor Upcase
IF SHE WEIGHS THE SAME AS A DUCK, SHE'S MADE OF WOOD
Using Processor Downcase
if she weighs the same as a duck, she's made of wood
Using Processor Splitter
[If, she, weighs, the, same, as, a, duck,, she's, made, of,
wood]
*/