// [email protected]
// Decorator design pattern in Java
// 2026-05-07
// tested on Win with javac 21.0.2

import java.util.*;

// interface was added second to have an abstraction
// an not to overload the Word class
interface Gettable {
    public String get();

}
// this was the first class to add,
// we wanted to have a word which we decided
// to be able to modify late
class Word implements Gettable {
    private String word;
    public Word(String word){
        this.word = word;
    }
    public String get(){
        return word;
    }
}

// third, now we can add the class to implement
// the Decorator pattern, i.e. WordDecorator acts
// like a Proxy and also satisfies the Gettable interface
// (note both the composition and the inheritence).
// We make this class abstract because it is designed
// to be inherited by the derived classes (decorators) below
abstract class WordDecorator implements Gettable {
    protected Gettable gettable;
    public WordDecorator(Gettable gettable){
        this.gettable = gettable;
    }
    abstract public String get();
}
// we add exclamation mark in the end regardless of the word
class ExclDecorator extends WordDecorator {
    public ExclDecorator(Gettable gettable){
        super(gettable);
    }
    public String get(){
        return gettable.get() + "!";
    }
}
// we add quotes around the word regardless of the word
class QuoteDecorator extends WordDecorator {
    public QuoteDecorator(Gettable gettable){
        super(gettable);
    }
    public String get(){
        return  "\"" + gettable.get() + "\"";
    }
}

public class Main {
    // sample delegates to simplify the call to
    // System.out.print and System.out.println
    public static void print(String text){
        System.out.print(text);
    }
    public static void println(String text){
        System.out.println(text);
    }
    public static void main(String[] args){
        // and here is the testing scenario:
        // simple word first, nothing unusual
        Gettable w = new Word("Hello");
        println(w.get());
        // we decorate the word
        Gettable d1 = new ExclDecorator(w);
        println(d1.get());
        // we also decorate the word, but differently
        Gettable d2 = new QuoteDecorator(w);
        println(d2.get());
        // and now the power of the Decorator:
        // we can stack the decorators on top of each other
        // which allows to dynamically change the functionality.
        // Each Decorator adds their own thing and builds
        // on the layer below.
        Gettable d3 = new QuoteDecorator(d1);
        println(d3.get());
    }
}