libjava/java/beans/Visibility.java

/* java.beans.Visibility
   Copyright (C) 1998, 1999 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
 
GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA.

As a special exception, if you link this library with other files to
produce an executable, this library does not by itself cause the
resulting executable to be covered by the GNU General Public License.
This exception does not however invalidate any other reasons why the
executable file might be covered by the GNU General Public License. */


package java.beans;

/**
 * Visibility is an interface a Bean may implement so that the environment
 * can tell the Bean whether there is a GUI or not, and so that the Bean
 * can tell the environment whether it needs one or can run without one.
 * <P>
 *
 * Sun decided not to use standard Introspection patterns so that these
 * methods did not get included when the Introspector made its sweep on
 * the class.
 *
 * @author John Keiser
 * @since JDK1.1
 * @version 1.1.0, 29 Jul 1998
 */

public interface Visibility {
	/**
	 * Tells whether the Bean can run without a GUI or not.
	 * @return false if Bean can run without a GUI, else true.
	 */
	public abstract boolean needsGui();

	/**
	 * Tells whether Bean is trying not to use the GUI.
	 * If needsGui() is true, this method should always return false.
	 * @return true if definitely not using GUI, otherwise false.
	 */
	public abstract boolean avoidingGui();

	/**
	 * Tells the Bean not to use GUI methods.
	 * If needsGUI() is false, then after this method is called,
	 * avoidingGui() should return true.
	 */
	public abstract void dontUseGui();

	/**
	 * Tells the Bean it may use the GUI.
	 * The Bean is not required to use the GUI in this case, it is
	 * merely being <EM>permitted</EM> to use it.  If needsGui() is
	 * false, avoidingGui() may return true or false after this method
	 * is called.
	 */
	public abstract void okToUseGui();
}