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 );
}
}