//
// another example of the Java AWT, showing use of List class.
// see class definition and main method for details.
//
import java.awt.* ;
import java.awt.event.* ;

//
// a ListExample object is a CloseableFrame containing a List and a
//      Label.  depending on the arguments to the constructor, 
//      multiple selections may or may not be allowed.  when the
//      user makes a selections, the current selections are displayed
//      in the Label.
// here, *Listeners are implemented using anonymous classes.  compare
//      with ListExample.
//
class ListExampleAlt extends CloseableFrame {

        List l ;
        Label display ;

        ListExampleAlt(boolean multi, String[] items) {

                super("ListExampleAlt") ;
                setLayout(new BorderLayout()) ;

                // make list with input items.  second argument
                //      specifies how many items to display --
                //      set to items.length/2 initially to show
                //      automatic scrollbar.
                l = new List(items.length / 2, multi) ;
                for (int i = 0 ; i < items.length ; i++) 
                        l.add(items[i]) ;
                display = new Label("nothing selected") ;

                // action to be performed when user clicks on an item 
                //      (select/deselect).
                l.addItemListener(new ItemListener() {
                        public void itemStateChanged(ItemEvent e) {
                                setDisplay("ItemEvent") ;
                        }
                } ) ;

                // action to be performed when user double-clicks on 
                //      an item.
                l.addActionListener(new ActionListener() {
                        public void actionPerformed(ActionEvent e) {
                                setDisplay("ActionEvent") ;
                        }
                } ) ;

                add(l, "Center") ;
                add(display, "South") ;

                pack() ;
                show() ;
        }

        // displays current selection(s) in Label.
        // should probably be declared private, but calling a
        //      private method from an anonymous inner class (as above)
        //      apparently triggers a compiler bug, causing the 
        //      compiler to hang!).
        void setDisplay(String event) {
                String itemsSel[] = l.getSelectedItems() ;
                String s ;
                if (itemsSel.length == 0) {
                        s = "nothing selected" ;
                }
                else {
                        StringBuffer sb = new StringBuffer("selected") ;
                        for (int i = 0 ; i < itemsSel.length ; i++) 
                                sb.append(" " + itemsSel[i]) ;
                        s = sb.toString() ;
                }
                display.setText(event + ":  " + s) ;
        }

        //
        // ---- main ---------------------------------------------------
        //
        // command-line arguments are y/n (multiple selections allowed),
        //      elements of List.
        //
        public static void main(String[] args) {

                if (args.length < 2) {
                        System.out.println("Arguments are y/n, " +
                                "list items") ;
                        System.exit(-1) ;
                }

                boolean multi = args[0].equals("y") ;

                String[] s = new String[args.length-1] ;
                for (int i = 0 ; i < s.length ; i++) 
                        s[i] = args[i+1] ;

                ListExampleAlt l = new ListExampleAlt(multi, s) ;
        }
}