// Purpose.?Chain of Responsibility and Command demo
//
// Chain of Responsibility -
// 1. Base class maintains a "next" pointer
// 2. Each "node" object evaluates each request
// 3. Node object may pass on a request to the
//  ?next node
// 4. Client "launches and leaves" each request
//
// Command -
// 5. Base class specifies an "execute" method
// 6. Derived classes call a method on an object

import java.awt.*;

public class CommandChainDemo {

interface Command {
    ? public void execute( Component c ); //// 5 \\\\
}
static class Back implements Command {
    ?private Color color;
    ?public Back( Color c ) { color = c; }
    ?public void execute( Component c ) { c.setBackground( color ); }?// 6 \\
}
static class Fore implements Command {
    ?private Color color;
    ?public Fore( Color c ) { color = c; }
    ?public void execute( Component c ) { c.setForeground( color ); }
}

static class ChainNode extends Button {
?/span>private ChainNode next; //// 1 \\\\

    ?public ChainNode( String name, ChainNode nx ) {
super( name );
setFont( new Font( "SansSerif", Font.BOLD, 30 ) );
next = nx;
    ? }
    ?public void process( Command cmd ) {
cmd.execute( this ); //// 2 \\\\
if (next != null) next.process( cmd ); //// 3 \\\\
}? }

public static ChainNode createChain( Frame f ) {
    ? ChainNode last = new ChainNode( "third",?null );
    ?ChainNode middle = new ChainNode( "second", last );
    ? ChainNode first?= new ChainNode( "first",?middle );
    ?f.add( first );?f.add( middle );?f.add( last );
    ? return first;
}

public static void main( String[] args ) {
    ?Frame f = new Frame( "ChainCommandDemo" );
    ? f.setLayout( new FlowLayout() );
    ?ChainNode root = createChain( f );
    ?f.pack();
    ?f.setVisible( true );

    ?Command[] cmds = { new Back( Color.cyan ), new Fore( Color.blue),
new Back( Color.yellow ), new Fore( Color.red) };
    ?for (int i=0; i < cmds.length; i++) {
Read.aString();
root.process( cmds[i] ); //// 4 \\\\
}?}? }