Graphical User Interfaces - Java - page 574

text = new new JTextArea ( 40 , 40 );

cp . add ( text , BorderLayout . CENTER );
ok = new new JButton ( "Close" );

cp . add ( ok , BorderLayout . SOUTH );
ok . addActionListener ( new new ActionListener () {

public public void void actionPerformed ( ActionEvent evt ) {

dispose ();

}

});
pack ();

}

/** Display the stackTrace from the given Throwable in this Dialog. */
void void showStackTrace ( Throwable exc ) {

CharArrayWriter buff = new new CharArrayWriter ();

PrintWriter pw = new new PrintWriter ( buff );

exc . printStackTrace ( pw );
pw . close ();
text . setText ( buff . toString ());
setVisible ( true true );

}

}

See the program ErrorUtilTest in the darwinsys/src/test/java directory for an example of
running this program directly, and see ErrorUtilCatchTest in the same directory for an ex-
ample of using it with uncaught exceptions from the GUI thread as described.

Getting Program Output into a Window

Problem

You want to capture an input/output stream and display it in a text field.

Solution

The easy way is to subclass OutputStream or Writer as appropriate, and override just the
methods needed to get characters copied into the JTextArea . You may also want to redirect
System.out and System.err to the stream; see Discussion .