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java.beans.beancontext

Interface BeanContextChild

Known Subinterfaces:
BeanContext, BeanContextServices
Known Implementing Classes:
BeanContextChildSupport, BeanContextServicesSupport, BeanContextSupport
public interface BeanContextChild
Beans implement this to get information about the execution environment and its services and to be placed in the hierarchy.

The difference between a BeanContext and a BeanContextChild, mainly, is that a BeanContext may be a parent.

BeanContextChild instances will be serialized at some point in their life, but you need to make sure your bean context does not contain a serializable reference (directly or indirectly) to the parent BeanContext, to any of the other BeanContexts in the tree, or to any resources obtained via the BeanContextServices interface. One way to do this is to mark any fields that contain such references as transient. Another way is to use a custom serializer.

If you do not do this, when the BeanContext is serialized, all the other BeanContexts and other unnecessary things will be serialized along with it.

Before dying, a BeanContextChild should call getBeanContext().remove(this) to detach from the hierarchy and exit cleanly.

Since:
JDK1.2
See Also:
BeanContext

Method Summary

void
addPropertyChangeListener(String prop, PropertyChangeListener listener)
Add a listener that will be notified when a specific property changes.
void
addVetoableChangeListener(String prop, VetoableChangeListener listener)
Add a listener that will be notified when a specific property change is requested (a PropertyVetoException may be thrown) as well as after the change is successfully made.
BeanContext
getBeanContext()
Get the parent BeanContext.
void
removePropertyChangeListener(String prop, PropertyChangeListener listener)
Remove a listener to a certain property.
void
removeVetoableChangeListener(String prop, VetoableChangeListener listener)
Remove a listener to a certain property.
void
setBeanContext(BeanContext parent)
Set the parent BeanContext.

Method Details

addPropertyChangeListener

public void addPropertyChangeListener(String prop,
                                      PropertyChangeListener listener)
Add a listener that will be notified when a specific property changes.
Parameters:
prop - the name of the property to listen on
listener - the listener to listen on the property.

addVetoableChangeListener

public void addVetoableChangeListener(String prop,
                                      VetoableChangeListener listener)
Add a listener that will be notified when a specific property change is requested (a PropertyVetoException may be thrown) as well as after the change is successfully made.
Parameters:
prop - the name of the property to listen on
listener - the listener to listen on the property.

getBeanContext

public BeanContext getBeanContext()
Get the parent BeanContext.
Returns:
the parent BeanContext.

removePropertyChangeListener

public void removePropertyChangeListener(String prop,
                                         PropertyChangeListener listener)
Remove a listener to a certain property.
Parameters:
prop - the name of the property being listened on
listener - the listener listening on the property.

removeVetoableChangeListener

public void removeVetoableChangeListener(String prop,
                                         VetoableChangeListener listener)
Remove a listener to a certain property.
Parameters:
prop - the name of the property being listened on
listener - the listener listening on the property.

setBeanContext

public void setBeanContext(BeanContext parent)
            throws PropertyVetoException
Set the parent BeanContext.

This method is called from BeanContext.add() and should not be called directly.

When this Object is being added to a new BeanContext or moved from an old one, a non-null value will be passed in.

When this Object is being removed from the current BeanContext, setBeanContext() will receive the parameter null.

When being removed from the current BeanContext, it is the BeanContextChild's responsibility to release all services it has obtained.

This change should generate PropertyChangeEvent and VetoableChangeEvents with the property name "beanContext". If the change is vetoed, it must re-throw the exception and not change anything. In this way, the parent BeanContextChild, who has registered himself with you, will have a chance to remove this child from its collection.

If the Bean does not wish to change the parent or be removed from one, it may throw the PropertyVetoException. If you veto a setBeanContext(null) call, then you should try your hardest to remedy whatever problem is keeping you from being removed from the BeanContext so that you can not veto it the next time. Otherwise, nasty pathological recursion stuff could occur in certain situations.

If you do veto the change, you must first back out any changes you made prior to the veto. Best not to make any such changes prior to the veto in the first place.

This method is called from BeanContext.add() and should not be called directly.

Parameters:
parent - the new parent for the BeanContextChild, or null to signify removal from a tree.
Throws:
PropertyVetoException - if the BeanContextChild implementor does not wish to have its parent changed.
java.beans.beancontext.BeanContextChild Copyright (C) 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.

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