// Decorator
//   Increment "wraps" Dubble "wraps" Increment "wraps" Core

interface LCD {
  static final StringBuffer indent = new StringBuffer();
  void processNumber( int in );
}

class Core implements LCD {
  public void processNumber( int in ) {
    System.out.println( indent.toString() + "Core ------ " + in );
} }

abstract class Decorator implements LCD {
  private LCD inner;
  public Decorator( LCD in ) { inner = in; }
  public void processNumber( int in ) {
    indent.append( "  " );
    inner.processNumber( in );
    indent.setLength( indent.length() - 2 );
} }

class Increment extends Decorator {
  public Increment( LCD inner ) { super( inner ); }
  public void processNumber( int in ) {
    System.out.println( indent.toString() + "Increment - " + in );
    super.processNumber( in + 1 );
    System.out.println( indent.toString() + "Increment - " + in );
} }

class Dubble extends Decorator {
  public Dubble( LCD inner ) { super( inner ); }
  public void processNumber( int in ) {
    System.out.println( indent.toString() + "Dubble ---- " + in );
    super.processNumber( in * 2 );
    System.out.println( indent.toString() + "Dubble ---- " + in );
} }

public class DecoratorDemo {
  public static void main( String[] args ) {
    LCD layers = new Increment( new Dubble( new Increment(
                                new Dubble( new Core() ))));
    for (int i=5; i < 7; i++)
      layers.processNumber( i );
} }

/************
Increment - 5
  Dubble ---- 6
    Increment - 12
      Dubble ---- 13
        Core ------ 26
      Dubble ---- 13
    Increment - 12
  Dubble ---- 6
Increment - 5
Increment - 6
  Dubble ---- 7
    Increment - 14
      Dubble ---- 15
        Core ------ 30
      Dubble ---- 15
    Increment - 14
  Dubble ---- 7
Increment - 6
************/