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jeremybenn |
/* java.beans.beancontext.BeanContextChild
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Copyright (C) 1999 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., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 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.beancontext;
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import java.beans.PropertyChangeListener;
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import java.beans.PropertyVetoException;
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import java.beans.VetoableChangeListener;
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/**
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* Beans implement this to get information about the execution environment and
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* its services and to be placed in the hierarchy.
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* <P>
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*
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* The difference between a <code>BeanContext</code> and a
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* <code>BeanContextChild</code>, mainly, is that a
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* <code>BeanContext</code> may be a parent.
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* <P>
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*
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* <code>BeanContextChild</code> instances will be serialized at some
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* point in their life, but you need to make sure your bean context does
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* not contain a serializable reference (directly or indirectly) to the
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* parent <code>BeanContext</code>, to any of the other
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* <code>BeanContext</code>s in the tree, or to any resources obtained
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* via the <code>BeanContextServices</code> interface. One way to do this
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* is to mark any fields that contain such references as
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* <code>transient</code>. Another way is to use a custom serializer.
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* <P>
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*
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* If you do not do this, when the <code>BeanContext</code> is serialized,
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* all the other <code>BeanContext</code>s and other unnecessary things
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* will be serialized along with it.
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* <P>
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*
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* Before dying, a <code>BeanContextChild</code> should call
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* <code>getBeanContext().remove(this)</code> to detach from the
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* hierarchy and exit cleanly.
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*
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* @author John Keiser
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* @since JDK1.2
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* @see java.beans.beancontext.BeanContext
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*/
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public interface BeanContextChild {
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/**
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* Set the parent <code>BeanContext</code>.
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* <P>
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*
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* This method is called from <code>BeanContext.add()</code> and
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* should not be called directly.
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* <P>
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*
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* When this Object is being added to a new BeanContext or moved
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* from an old one, a non-null value will be passed in.
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* <P>
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*
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* When this Object is being removed from the current
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* <code>BeanContext</code>, <code>setBeanContext()</code> will
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* receive the parameter <code>null</code>.
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* <P>
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*
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* When being removed from the current <code>BeanContext</code>,
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* it is the <code>BeanContextChild</code>'s responsibility to
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* release all services it has obtained.
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* <P>
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*
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* This change should generate <code>PropertyChangeEvent</code>
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* and <code>VetoableChangeEvent</code>s with the property name
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* "beanContext". If the change is vetoed, it must re-throw the
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* exception and not change anything. In this way, the parent
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* <code>BeanContextChild</code>, who has registered himself with
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* you, will have a chance to remove this child from its
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* collection.
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* <P>
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*
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* If the Bean does not wish to change the parent or be removed
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* from one, it may throw the <code>PropertyVetoException</code>.
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* If you veto a <code>setBeanContext(null)</code> call, then you
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* should try your hardest to remedy whatever problem is keeping
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* you from being removed from the <code>BeanContext</code> so
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* that you can <em>not</em> veto it the next time.
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* Otherwise, nasty pathological recursion stuff could occur in
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* certain situations.
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* <P>
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*
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* If you do veto the change, you must first back out any changes
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* you made prior to the veto. Best not to make any such changes
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* prior to the veto in the first place.
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* <P>
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*
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* This method is called from <code>BeanContext.add()</code> and
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* should not be called directly.
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*
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* @param parent the new parent for the <code>BeanContextChild</code>,
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* or <code>null</code> to signify removal from a tree.
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* @exception PropertyVetoException if the
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* <code>BeanContextChild</code> implementor does not
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* wish to have its parent changed.
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*/
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void setBeanContext(BeanContext parent)
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throws PropertyVetoException;
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/**
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* Get the parent <code>BeanContext</code>.
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* @return the parent <code>BeanContext</code>.
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*/
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BeanContext getBeanContext();
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/**
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* Add a listener that will be notified when a specific property changes.
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* @param prop the name of the property to listen on
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* @param listener the listener to listen on the property.
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*/
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void addPropertyChangeListener(String prop, PropertyChangeListener listener);
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/**
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* Remove a listener to a certain property.
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* @param prop the name of the property being listened on
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* @param listener the listener listening on the property.
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*/
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void removePropertyChangeListener(String prop, PropertyChangeListener listener);
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/**
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* Add a listener that will be notified when a specific property
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* change is requested (a PropertyVetoException may be thrown) as
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* well as after the change is successfully made.
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*
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* @param prop the name of the property to listen on
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* @param listener the listener to listen on the property.
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*/
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void addVetoableChangeListener(String prop, VetoableChangeListener listener);
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/**
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* Remove a listener to a certain property.
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* @param prop the name of the property being listened on
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* @param listener the listener listening on the property.
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*/
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void removeVetoableChangeListener(String prop, VetoableChangeListener listener);
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}
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