74 lines
3.2 KiB
Java
74 lines
3.2 KiB
Java
/* VetoableChangeListener.java -- listen for a change which can be vetoed
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Copyright (C) 1998, 2000, 2002 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.beans;
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import java.util.EventListener;
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/**
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* VetoableChangeListener allows a class to monitor proposed changes to
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* properties of a Bean and, if desired, prevent them from occurring. A
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* vetoableChange() event will be fired <em>after</em> the property change has
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* been requested, but before it is permanent. If any listener rejects the
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* change by throwing the PropertyChangeException, a new vetoableChange()
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* event will be fired to all listeners who received a vetoableChange() event
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* in the first place, informing them to revert back to the old value. Thus,
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* the listener that threw the exception the first time should be prepared
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* to rethrow it the second time. The value, of course, never actually changed.
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*
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* <p><strong>Note:</strong> This class may not be reliably used to determine
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* whether a property has actually changed. Use the PropertyChangeListener
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* interface for that instead.
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*
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* @author John Keiser
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* @see java.beans.PropertyChangeListener
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* @see java.beans.VetoableChangeSupport
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* @since 1.1
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* @status updated to 1.4
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*/
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public interface VetoableChangeListener extends EventListener
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{
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/**
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* Fired before a Bean's property changes.
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*
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* @param e the change (containing the old and new values)
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* @throws PropertyVetoException if the change is vetoed by the listener
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*/
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void vetoableChange(PropertyChangeEvent e) throws PropertyVetoException;
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} // interface VetoableChangeListener
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