//
// another example of the Java AWT, showing different ways to process
//      changes in TextField Objects.
// see class definition for details.
//
// observation suggests that on some systems, when "all" is chosen
//      this program may not be able to keep up with a fast-typing
//      user, leading to very strange behavior (jumbled-up text in
//      the TextField being edited).
//
import java.awt.* ;
import java.awt.event.* ;

//
// a MirrorLine object is a CloseableFrame containing two TextField 
//      objects whose contents are to be kept "in sync" (equivalent).  
//      if syncOnAll = true, the fields are resynchronized every time 
//      one of them changes; otherwise, the fields are resynchronized 
//      only when the user presses "return" in the field currently 
//      receiving keyboard input.
//
class MirrorLine extends CloseableFrame {

        MirrorLine(boolean syncOnAll) {

                super("MirrorLine") ;
                // use BorderLayout so TextField objects (at "north"
                //      and "south" positions) keep their original 
                //      height.
                setLayout(new BorderLayout()) ;

                String startString = "Hello!" ;
                int startWidth = 40 ;

                TextField t1 = new TextField(startString, startWidth) ;
                TextField t2 = new TextField(startString, startWidth) ;
                add(t1, "North") ;
                add(t2, "South") ;

                if (syncOnAll) {
                        // one adapter has source t1 and target t2
                        t1.addTextListener(new SyncAllAdapter(t2)) ;
                        // other adapter has source t2 and target t1
                        t2.addTextListener(new SyncAllAdapter(t1)) ;
                }
                else {
                        // one adapter has source t1 and target t2
                        t1.addActionListener(
                                new SyncReturnAdapter(t2)) ;
                        // other adapter has source t2 and target t1
                        t2.addActionListener(
                                new SyncReturnAdapter(t1)) ;
                }
                        
                pack() ;
                show() ;
        }

        //
        // ---- main ---------------------------------------------------
        //
        // command-line argument:  all/return
        //      "all" -> syncOnAll = true (see comments for class).
        //      "return" -> syncOnAll = false.
        //
        public static void main(String[] args) {

                if (args.length < 1) {
                        System.out.println("Argument is all/return") ;
                        System.exit(-1) ;
                }

                boolean syncOnAll = false ;
                if (args[0].equals("all")) {
                        syncOnAll = true ;
                }
                else if (!args[0].equals("return")) {
                        System.out.println("Argument is all/return") ;
                        System.exit(-1) ;
                }

                MirrorLine m = new MirrorLine(syncOnAll) ;
        }

        //
        // ---- inner classes ------------------------------------------
        //

        //
        // a SyncAllAdapter object resyncs its target and source
        //      TextField objects every time the source's text changes.
        //
        class SyncAllAdapter implements TextListener {
                TextField target ;
                SyncAllAdapter(TextField t) {
                        target = t ;
                }
                public void textValueChanged(TextEvent e) {
                        TextField src = (TextField) e.getSource() ;
                        if (!target.getText().equals(src.getText())) 
                                        target.setText(src.getText()) ;
                }
        }
        
        //
        // a SyncReturnAdapter object resyncs its target and source
        //      TextField objects every time the user presses "return" 
        //      in its source field.
        //
        class SyncReturnAdapter implements ActionListener {
                TextField target ;
                SyncReturnAdapter(TextField t) {
                        target = t ;
                }
                public void actionPerformed(ActionEvent e) {
                        TextField src = (TextField) e.getSource() ;
                        if (!target.getText().equals(src.getText())) 
                                target.setText(src.getText()) ;
                }
        }
}