Text based java application

Question

The main idea is to try to create an application that will look like a standard Linux-type terminal. Now I am limited to Java, and this is what I want.

• Main window (independent JFrame) with top menu (well, I know how to do this)
• The entire area under the menu bar is for the “console”, with which users can interact by entering commands (I have no idea about this).

Is there any simple enough way to do such a thing. This should be a word processing application and should work independently of the system and autonomously. All working logic must be derived from user input.

Any ideas?

Answer 1

The "console" can be implemented using JTextPane . Whenever the window has focus, you can write any click on the text field and analyze it, execute each time you press 'Enter' (use KeyListener and implement keyTyped ).

Answer 2

I think you need two text components, a text area and a text field.

If the user enters text in the text box below and calls Enter , the text moves to the text area where it is no longer being edited. Processing is then performed, as a result, the result (or multiples) is printed into the text area, and the next line can be entered.

The top area may have a JScrollPane . One way or another, buffering must be handled.

Here is a simple, complete, and executable example:

 import javax.swing.*; import java.awt.*; import java.awt.event.*; import java.util.*; import javax.swing.plaf.ActionMapUIResource; /** CmdPrompt @author Stefan Wagner @date Mi 25. Apr 17:27:19 CEST 2012 (c) GPLv3 */ public class CmdPrompt extends JFrame { private static final String progname = "CmdPrompt 0.1"; private JTextField input; private JTextArea history; public CmdPrompt () { super (progname); JPanel mainpanel = new JPanel (); mainpanel.setLayout (new BorderLayout ()); this.getContentPane ().add (mainpanel); input = new JTextField (80); history = new JTextArea (); mainpanel.add (history, BorderLayout.CENTER); mainpanel.add (input, BorderLayout.SOUTH); ActionMap actionMap = new ActionMapUIResource (); actionMap.put ("enter", new AbstractAction () { @Override public void actionPerformed (ActionEvent e) { String cmd = input.getText (); String sofar = history.getText (); history.setText (sofar + "\n> " + cmd + "\n" + processCmd (cmd)); input.setText (""); } }); InputMap keyMap = new ComponentInputMap (input); keyMap.put (KeyStroke.getKeyStroke (KeyEvent.VK_ENTER, 0), "enter"); SwingUtilities.replaceUIActionMap (input, actionMap); SwingUtilities.replaceUIInputMap (input, JComponent.WHEN_IN_FOCUSED_WINDOW, keyMap); setSize (400, 400); setLocation (100, 100); setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE); setVisible (true); } private void center () { Toolkit tk = Toolkit.getDefaultToolkit (); Dimension screen = tk.getScreenSize (); Dimension d = getSize (); setLocation ((screen.width - d.width) / 2, (screen.height - d.height) / 2); } public static String processCmd (String cmd) { String arr [] = cmd.split (" "); if ("rev".equals (arr [0])) { return reverse (cmd.substring (4)); } else if ("upp".equals (arr [0])) { return (cmd.substring (4)).toUpperCase (); } else if ("low".equals (arr [0])) { return (cmd.substring (4)).toLowerCase (); } else if ("help".equals (arr [0])) { return ("rev, upp, low, help"); } return "unknown command"; } public static String reverse (String cmd) { return (cmd.length () < 2) ? cmd : reverse (cmd.substring (1)) + cmd.charAt (0); } public static void main (final String args []) { Runnable runner = new Runnable () { public void run () { new CmdPrompt (); } }; EventQueue.invokeLater (runner); } }