| /* |
| * Copyright (c) 1998, 2004, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code 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 |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package java.beans.beancontext; |
| |
| import java.beans.PropertyChangeEvent; |
| import java.beans.PropertyChangeListener; |
| import java.beans.PropertyChangeSupport; |
| |
| import java.beans.VetoableChangeListener; |
| import java.beans.VetoableChangeSupport; |
| |
| import java.beans.PropertyVetoException; |
| |
| import java.io.IOException; |
| import java.io.ObjectInputStream; |
| import java.io.ObjectOutputStream; |
| import java.io.Serializable; |
| |
| /** |
| * <p> |
| * This is a general support class to provide support for implementing the |
| * BeanContextChild protocol. |
| * |
| * This class may either be directly subclassed, or encapsulated and delegated |
| * to in order to implement this interface for a given component. |
| * </p> |
| * |
| * @author Laurence P. G. Cable |
| * @since 1.2 |
| * |
| * @see java.beans.beancontext.BeanContext |
| * @see java.beans.beancontext.BeanContextServices |
| * @see java.beans.beancontext.BeanContextChild |
| */ |
| |
| public class BeanContextChildSupport implements BeanContextChild, BeanContextServicesListener, Serializable { |
| |
| static final long serialVersionUID = 6328947014421475877L; |
| |
| /** |
| * construct a BeanContextChildSupport where this class has been |
| * subclassed in order to implement the JavaBean component itself. |
| */ |
| |
| public BeanContextChildSupport() { |
| super(); |
| |
| beanContextChildPeer = this; |
| |
| pcSupport = new PropertyChangeSupport(beanContextChildPeer); |
| vcSupport = new VetoableChangeSupport(beanContextChildPeer); |
| } |
| |
| /** |
| * construct a BeanContextChildSupport where the JavaBean component |
| * itself implements BeanContextChild, and encapsulates this, delegating |
| * that interface to this implementation |
| */ |
| |
| public BeanContextChildSupport(BeanContextChild bcc) { |
| super(); |
| |
| beanContextChildPeer = (bcc != null) ? bcc : this; |
| |
| pcSupport = new PropertyChangeSupport(beanContextChildPeer); |
| vcSupport = new VetoableChangeSupport(beanContextChildPeer); |
| } |
| |
| /** |
| * Sets the <code>BeanContext</code> for |
| * this <code>BeanContextChildSupport</code>. |
| * @param bc the new value to be assigned to the <code>BeanContext</code> |
| * property |
| * @throws <code>PropertyVetoException</code> if the change is rejected |
| */ |
| public synchronized void setBeanContext(BeanContext bc) throws PropertyVetoException { |
| if (bc == beanContext) return; |
| |
| BeanContext oldValue = beanContext; |
| BeanContext newValue = bc; |
| |
| if (!rejectedSetBCOnce) { |
| if (rejectedSetBCOnce = !validatePendingSetBeanContext(bc)) { |
| throw new PropertyVetoException( |
| "setBeanContext() change rejected:", |
| new PropertyChangeEvent(beanContextChildPeer, "beanContext", oldValue, newValue) |
| ); |
| } |
| |
| try { |
| fireVetoableChange("beanContext", |
| oldValue, |
| newValue |
| ); |
| } catch (PropertyVetoException pve) { |
| rejectedSetBCOnce = true; |
| |
| throw pve; // re-throw |
| } |
| } |
| |
| if (beanContext != null) releaseBeanContextResources(); |
| |
| beanContext = newValue; |
| rejectedSetBCOnce = false; |
| |
| firePropertyChange("beanContext", |
| oldValue, |
| newValue |
| ); |
| |
| if (beanContext != null) initializeBeanContextResources(); |
| } |
| |
| /** |
| * Gets the nesting <code>BeanContext</code> |
| * for this <code>BeanContextChildSupport</code>. |
| * @return the nesting <code>BeanContext</code> for |
| * this <code>BeanContextChildSupport</code>. |
| */ |
| public synchronized BeanContext getBeanContext() { return beanContext; } |
| |
| /** |
| * Add a PropertyChangeListener for a specific property. |
| * The same listener object may be added more than once. For each |
| * property, the listener will be invoked the number of times it was added |
| * for that property. |
| * If <code>name</code> or <code>pcl</code> is null, no exception is thrown |
| * and no action is taken. |
| * |
| * @param name The name of the property to listen on |
| * @param pcl The <code>PropertyChangeListener</code> to be added |
| */ |
| public void addPropertyChangeListener(String name, PropertyChangeListener pcl) { |
| pcSupport.addPropertyChangeListener(name, pcl); |
| } |
| |
| /** |
| * Remove a PropertyChangeListener for a specific property. |
| * If <code>pcl</code> was added more than once to the same event |
| * source for the specified property, it will be notified one less time |
| * after being removed. |
| * If <code>name</code> is null, no exception is thrown |
| * and no action is taken. |
| * If <code>pcl</code> is null, or was never added for the specified |
| * property, no exception is thrown and no action is taken. |
| * |
| * @param name The name of the property that was listened on |
| * @param pcl The PropertyChangeListener to be removed |
| */ |
| public void removePropertyChangeListener(String name, PropertyChangeListener pcl) { |
| pcSupport.removePropertyChangeListener(name, pcl); |
| } |
| |
| /** |
| * Add a VetoableChangeListener for a specific property. |
| * The same listener object may be added more than once. For each |
| * property, the listener will be invoked the number of times it was added |
| * for that property. |
| * If <code>name</code> or <code>vcl</code> is null, no exception is thrown |
| * and no action is taken. |
| * |
| * @param name The name of the property to listen on |
| * @param vcl The <code>VetoableChangeListener</code> to be added |
| */ |
| public void addVetoableChangeListener(String name, VetoableChangeListener vcl) { |
| vcSupport.addVetoableChangeListener(name, vcl); |
| } |
| |
| /** |
| * Removes a <code>VetoableChangeListener</code>. |
| * If <code>pcl</code> was added more than once to the same event |
| * source for the specified property, it will be notified one less time |
| * after being removed. |
| * If <code>name</code> is null, no exception is thrown |
| * and no action is taken. |
| * If <code>vcl</code> is null, or was never added for the specified |
| * property, no exception is thrown and no action is taken. |
| * |
| * @param name The name of the property that was listened on |
| * @param vcl The <code>VetoableChangeListener</code> to be removed |
| */ |
| public void removeVetoableChangeListener(String name, VetoableChangeListener vcl) { |
| vcSupport.removeVetoableChangeListener(name, vcl); |
| } |
| |
| /** |
| * A service provided by the nesting BeanContext has been revoked. |
| * |
| * Subclasses may override this method in order to implement their own |
| * behaviors. |
| * @param bcsre The <code>BeanContextServiceRevokedEvent</code> fired as a |
| * result of a service being revoked |
| */ |
| public void serviceRevoked(BeanContextServiceRevokedEvent bcsre) { } |
| |
| /** |
| * A new service is available from the nesting BeanContext. |
| * |
| * Subclasses may override this method in order to implement their own |
| * behaviors |
| * @param bcsae The BeanContextServiceAvailableEvent fired as a |
| * result of a service becoming available |
| * |
| */ |
| public void serviceAvailable(BeanContextServiceAvailableEvent bcsae) { } |
| |
| /** |
| * Gets the <tt>BeanContextChild</tt> associated with this |
| * <tt>BeanContextChildSupport</tt>. |
| * |
| * @return the <tt>BeanContextChild</tt> peer of this class |
| */ |
| public BeanContextChild getBeanContextChildPeer() { return beanContextChildPeer; } |
| |
| /** |
| * Reports whether or not this class is a delegate of another. |
| * |
| * @return true if this class is a delegate of another |
| */ |
| public boolean isDelegated() { return !this.equals(beanContextChildPeer); } |
| |
| /** |
| * Report a bound property update to any registered listeners. No event is |
| * fired if old and new are equal and non-null. |
| * @param name The programmatic name of the property that was changed |
| * @param oldValue The old value of the property |
| * @param newValue The new value of the property |
| */ |
| public void firePropertyChange(String name, Object oldValue, Object newValue) { |
| pcSupport.firePropertyChange(name, oldValue, newValue); |
| } |
| |
| /** |
| * Report a vetoable property update to any registered listeners. |
| * If anyone vetos the change, then fire a new event |
| * reverting everyone to the old value and then rethrow |
| * the PropertyVetoException. <P> |
| * |
| * No event is fired if old and new are equal and non-null. |
| * <P> |
| * @param name The programmatic name of the property that is about to |
| * change |
| * |
| * @param oldValue The old value of the property |
| * @param newValue - The new value of the property |
| * |
| * @throws PropertyVetoException if the recipient wishes the property |
| * change to be rolled back. |
| */ |
| public void fireVetoableChange(String name, Object oldValue, Object newValue) throws PropertyVetoException { |
| vcSupport.fireVetoableChange(name, oldValue, newValue); |
| } |
| |
| /** |
| * Called from setBeanContext to validate (or otherwise) the |
| * pending change in the nesting BeanContext property value. |
| * Returning false will cause setBeanContext to throw |
| * PropertyVetoException. |
| * @param newValue the new value that has been requested for |
| * the BeanContext property |
| * @return <code>true</code> if the change operation is to be vetoed |
| */ |
| public boolean validatePendingSetBeanContext(BeanContext newValue) { |
| return true; |
| } |
| |
| /** |
| * This method may be overridden by subclasses to provide their own |
| * release behaviors. When invoked any resources held by this instance |
| * obtained from its current BeanContext property should be released |
| * since the object is no longer nested within that BeanContext. |
| */ |
| |
| protected void releaseBeanContextResources() { |
| // do nothing |
| } |
| |
| /** |
| * This method may be overridden by subclasses to provide their own |
| * initialization behaviors. When invoked any resources requried by the |
| * BeanContextChild should be obtained from the current BeanContext. |
| */ |
| |
| protected void initializeBeanContextResources() { |
| // do nothing |
| } |
| |
| /** |
| * Write the persistence state of the object. |
| */ |
| |
| private void writeObject(ObjectOutputStream oos) throws IOException { |
| |
| /* |
| * dont serialize if we are delegated and the delegator isnt also |
| * serializable. |
| */ |
| |
| if (!equals(beanContextChildPeer) && !(beanContextChildPeer instanceof Serializable)) |
| throw new IOException("BeanContextChildSupport beanContextChildPeer not Serializable"); |
| |
| else |
| oos.defaultWriteObject(); |
| |
| } |
| |
| |
| /** |
| * Restore a persistent object, must wait for subsequent setBeanContext() |
| * to fully restore any resources obtained from the new nesting |
| * BeanContext |
| */ |
| |
| private void readObject(ObjectInputStream ois) throws IOException, ClassNotFoundException { |
| ois.defaultReadObject(); |
| } |
| |
| /* |
| * fields |
| */ |
| |
| /** |
| * The <code>BeanContext</code> in which |
| * this <code>BeanContextChild</code> is nested. |
| */ |
| public BeanContextChild beanContextChildPeer; |
| |
| /** |
| * The <tt>PropertyChangeSupport</tt> associated with this |
| * <tt>BeanContextChildSupport</tt>. |
| */ |
| protected PropertyChangeSupport pcSupport; |
| |
| /** |
| * The <tt>VetoableChangeSupport</tt> associated with this |
| * <tt>BeanContextChildSupport</tt>. |
| */ |
| protected VetoableChangeSupport vcSupport; |
| |
| protected transient BeanContext beanContext; |
| |
| /** |
| * A flag indicating that there has been |
| * at least one <code>PropertyChangeVetoException</code> |
| * thrown for the attempted setBeanContext operation. |
| */ |
| protected transient boolean rejectedSetBCOnce; |
| |
| } |
