doFactory.com

Question

How would I print the contents of the ArrayList in Java?Marked(***********) using System; using System.Collections; // "Component" abstract class DrawingElement { // Fields protected string name; // Constructors public DrawingElement( string name ) { this.name = name; } // Methods abstract public void Add( DrawingElement d ); abstract public void Remove( DrawingElement d ); abstract public void Display( int indent ); } // "Leaf" class PrimitiveElement : DrawingElement { // Constructors public PrimitiveElement( string name ) : base( name ) {} // Methods public override void Add( DrawingElement c ) { Console.WriteLine("Cannot Add"); } public override void Remove( DrawingElement c ) { Console.WriteLine("Cannot Remove"); } public override void Display( int indent ) { Console.WriteLine( new String( '-', indent ) + " draw a {0}", name ); } } // "Composite" class CompositeElement : DrawingElement { // Fields private ArrayList elements = new ArrayList(); // Constructors public CompositeElement( string name ) : base( name ) {} // Methods public override void Add( DrawingElement d ) { elements.Add( d ); } public override void Remove( DrawingElement d ) { elements.Remove( d ); } public override void Display( int indent ) (*************************) { Console.WriteLine( new String( '-', indent ) + (********************) "+ " + name ); // Display each child element on this node foreach( DrawingElement c in elements ) (*********************) c.Display( indent + 2 ); (********************) } } ///

/// CompositeApp test ///

public class CompositeApp { public static void Main( string[] args ) { // Create a tree structure CompositeElement root = new CompositeElement( "Picture" ); root.Add( new PrimitiveElement( "Red Line" )); root.Add( new PrimitiveElement( "Blue Circle" )); root.Add( new PrimitiveElement( "Green Box" )); CompositeElement comp = new CompositeElement( "Two Circles" ); comp.Add( new PrimitiveElement( "Black Circle" ) ); comp.Add( new PrimitiveElement( "White Circle" ) ); root.Add( comp ); // Add and remove a PrimitiveElement PrimitiveElement l = new PrimitiveElement( "Yellow Line" ); root.Add( l ); root.Remove( l ); // Recursively display nodes root.Display( 1 ); } }