beancontextsupport.java

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	boolean prev = serializing;

	serializing = true;

	int count = 0;

	synchronized(children) {
	    Iterator i = children.entrySet().iterator();

	    while (i.hasNext() && count < serializable) {
	        Map.Entry entry = (Map.Entry)i.next();

	        if (entry.getKey() instanceof Serializable) {
	      	    try {
		        oos.writeObject(entry.getKey());   // child
		        oos.writeObject(entry.getValue()); // BCSChild
		    } catch (IOException ioe) {
		        serializing = prev;
		        throw ioe;
		    }
		    count++;
	        }
	    }
	}
	
        serializing = prev;

	if (count != serializable) {
	    throw new IOException("wrote different number of children than expected");
	}

    }

    /**
     * Serialize the BeanContextSupport, if this instance has a distinct 
     * peer (that is this object is acting as a delegate for another) then
     * the children of this instance are not serialized here due to a 
     * 'chicken and egg' problem that occurs on deserialization of the 
     * children at the same time as this instance. 
     *
     * Therefore in situations where there is a distinct peer to this instance
     * it should always call writeObject() followed by writeChildren() and
     * readObject() followed by readChildren().
     *
     * @param oos the ObjectOutputStream
     */

    private synchronized void writeObject(ObjectOutputStream oos) throws IOException, ClassNotFoundException {
	serializing = true;

	synchronized (BeanContext.globalHierarchyLock) {
	    try {
	        oos.defaultWriteObject(); // serialize the BeanContextSupport object

	        bcsPreSerializationHook(oos);

	        if (serializable > 0 && this.equals(getBeanContextPeer()))
	            writeChildren(oos);

	        serialize(oos, (Collection)bcmListeners);
	    } finally {
	        serializing = false;
	    }
 	}
    }

    /**
     * When an instance of this class is used as a delegate for the
     * implementation of the BeanContext protocols (and its subprotocols)
     * there exists a 'chicken and egg' problem during deserialization 
     */

    public final void readChildren(ObjectInputStream ois) throws IOException, ClassNotFoundException {
	int count = serializable; 

	while (count-- > 0) {
	    Object                      child = null;
	    BeanContextSupport.BCSChild bscc  = null;
	  
	    try {
	        child = ois.readObject();
	        bscc  = (BeanContextSupport.BCSChild)ois.readObject();
	    } catch (IOException ioe) {
		continue;
	    } catch (ClassNotFoundException cnfe) {
		continue;
	    }


	    synchronized(child) {
		BeanContextChild bcc = null;

		try {
		    bcc = (BeanContextChild)child;
		} catch (ClassCastException cce) {
		    // do nothing;
		}

		if (bcc != null) {
		    try {
			bcc.setBeanContext(getBeanContextPeer());

	               bcc.addPropertyChangeListener("beanContext", childPCL);
	               bcc.addVetoableChangeListener("beanContext", childVCL);
	
		    } catch (PropertyVetoException pve) {
			continue;
		    }
		}

		childDeserializedHook(child, bscc);
	    }
	}
    }

    /**
     * deserialize contents ... if this instance has a distinct peer the
     * children are *not* serialized here, the peer's readObject() must call
     * readChildren() after deserializing this instance.
     */

    private synchronized void readObject(ObjectInputStream ois) throws IOException, ClassNotFoundException {

	synchronized(BeanContext.globalHierarchyLock) {
	    ois.defaultReadObject();

	    initialize();

	    bcsPreDeserializationHook(ois);

	    if (serializable > 0 && this.equals(getBeanContextPeer()))
	        readChildren(ois);

	    deserialize(ois, bcmListeners = new ArrayList(1));
	}
    }

    /**
     * subclasses may envelope to monitor veto child property changes.
     */

    public void vetoableChange(PropertyChangeEvent pce) throws PropertyVetoException {
	String propertyName = pce.getPropertyName();
	Object source	    = pce.getSource();

	synchronized(children) {
	    if ("beanContext".equals(propertyName) &&
	        containsKey(source)	               &&
	        !getBeanContextPeer().equals(pce.getNewValue())
	    ) {
	        if (!validatePendingRemove(source)) {
		    throw new PropertyVetoException("current BeanContext vetoes setBeanContext()", pce);
	        } else ((BCSChild)children.get(source)).setRemovePending(true);
	    }
	}
    }

    /**
     * subclasses may envelope to monitor child property changes.
     */

    public void propertyChange(PropertyChangeEvent pce) {
	String propertyName = pce.getPropertyName();
	Object source	    = pce.getSource();

	synchronized(children) {
	    if ("beanContext".equals(propertyName) &&
	        containsKey(source)		       &&
	        ((BCSChild)children.get(source)).isRemovePending()) {
	        BeanContext bc = getBeanContextPeer();

	        if (bc.equals(pce.getOldValue()) && !bc.equals(pce.getNewValue())) {
	            remove(source, false);
	        } else {
		    ((BCSChild)children.get(source)).setRemovePending(false);
	        }
	    }
        }
    }

    /**
     * <p>
     * Subclasses of this class may override, or envelope, this method to
     * add validation behavior for the BeanContext to examine child objects
     * immediately prior to their being added to the BeanContext. 
     * </p>
     *
     * @return true iff the child may be added to this BeanContext, otherwise false.
     */

    protected boolean validatePendingAdd(Object targetChild) {
	return true;
    }

    /**
     * <p>
     * Subclasses of this class may override, or envelope, this method to
     * add validation behavior for the BeanContext to examine child objects
     * immediately prior to their being removed from the BeanContext. 
     * </p>
     *
     * @return true iff the child may be removed from this BeanContext, otherwise false.
     */

    protected boolean validatePendingRemove(Object targetChild) {
	return true;
    }

    /**
     * subclasses may override this method to simply extend add() semantics
     * after the child has been added and before the event notification has
     * occurred. The method is called with the child synchronized.
     */

    protected void childJustAddedHook(Object child, BCSChild bcsc) {
    }

    /**
     * subclasses may override this method to simply extend remove() semantics
     * after the child has been removed and before the event notification has
     * occurred. The method is called with the child synchronized.
     */

    protected void childJustRemovedHook(Object child, BCSChild bcsc) {
    }

    /**
     * Gets the Component (if any) associated with the specified child.
     * @param child the specified child
     * @return the Component (if any) associated with the specified child.
     */
    protected static final Visibility getChildVisibility(Object child) {
	try {
	    return (Visibility)child;
	} catch (ClassCastException cce) {
	    return null;
	}
    }
 
    /**
     * Gets the Serializable (if any) associated with the specified Child
     * @param child the specified child
     * @return the Serializable (if any) associated with the specified Child
     */
    protected static final Serializable getChildSerializable(Object child) {
        try {
	    return (Serializable)child;
	} catch (ClassCastException cce) {
	    return null;
	}
    }

    /**
     * Gets the PropertyChangeListener 
     * (if any) of the specified child
     * @param child the specified child
     * @return the PropertyChangeListener (if any) of the specified child
     */
    protected static final PropertyChangeListener getChildPropertyChangeListener(Object child) {
	try {
	    return (PropertyChangeListener)child;
	} catch (ClassCastException cce) {
	    return null;
	}
    }

    /**
     * Gets the VetoableChangeListener 
     * (if any) of the specified child
     * @param child the specified child
     * @return the VetoableChangeListener (if any) of the specified child
     */
    protected static final VetoableChangeListener getChildVetoableChangeListener(Object child) {
	try {
	    return (VetoableChangeListener)child;
	} catch (ClassCastException cce) {
	    return null;
	}
    }

    /**
     * Gets the BeanContextMembershipListener 
     * (if any) of the specified child
     * @param child the specified child
     * @return the BeanContextMembershipListener (if any) of the specified child
     */
    protected static final BeanContextMembershipListener getChildBeanContextMembershipListener(Object child) {
	try {
	    return (BeanContextMembershipListener)child;
	} catch (ClassCastException cce) {
	    return null;
	}
    }

    /**
     * Gets the BeanContextChild (if any) of the specified child
     * @param child the specified child
     * @return  the BeanContextChild (if any) of the specified child
     * @throws  IllegalArgumentException if child implements both BeanContextChild and BeanContextProxy
     */
    protected static final BeanContextChild getChildBeanContextChild(Object child) {
        try {
	    BeanContextChild bcc = (BeanContextChild)child;

	    if (child instanceof BeanContextChild && child instanceof BeanContextProxy) 
		throw new IllegalArgumentException("child cannot implement both BeanContextChild and BeanContextProxy");
	    else
		return bcc;
	} catch (ClassCastException cce) {
	    try {
		return ((BeanContextProxy)child).getBeanContextProxy();
	    } catch (ClassCastException cce1) {
	        return null;
	    }
	}
    }

    /**
     * Fire a BeanContextshipEvent on the BeanContextMembershipListener interface
     */

    protected final void fireChildrenAdded(BeanContextMembershipEvent bcme) {
	Object[] copy;
							  
	synchronized(bcmListeners) { copy = bcmListeners.toArray(); }

	for (int i = 0; i < copy.length; i++)
	    ((BeanContextMembershipListener)copy[i]).childrenAdded(bcme);
    }

    /**
     * Fire a BeanContextshipEvent on the BeanContextMembershipListener interface
     */

    protected final void fireChildrenRemoved(BeanContextMembershipEvent bcme) {
	Object[] copy;
							  
	synchronized(bcmListeners) { copy = bcmListeners.toArray(); }

	for (int i = 0; i < copy.length; i++)
	    ((BeanContextMembershipListener)copy[i]).childrenRemoved(bcme);
    }

    /**
     * protected method called from constructor and readObject to initialize
     * transient state of BeanContextSupport instance.
     *
     * This class uses this method to instantiate inner class listeners used
     * to monitor PropertyChange and VetoableChange events on children.
     *
     * subclasses may envelope this method to add their own initialization
     * behavior
     */

    protected synchronized void initialize() {
	children     = new HashMap(serializable + 1);
	bcmListeners = new ArrayList(1);

	childPCL = new PropertyChangeListener() {

	    /*
	     * this adaptor is used by the BeanContextSupport class to forward
	     * property changes from a child to the BeanContext, avoiding 
	     * accidential serialization of the BeanContext by a badly 
	     * behaved Serializable child.
	     */

	    public void propertyChange(PropertyChangeEvent pce) {
	        BeanContextSupport.this.propertyChange(pce);
	    }
	};

	childVCL = new VetoableChangeListener() {

	    /*
	     * this adaptor is used by the BeanContextSupport class to forward
	     * vetoable changes from a child to the BeanContext, avoiding 
	     * accidential serialization of the BeanContext by a badly 
	     * behaved Serializable child.
	     */

	    public void vetoableChange(PropertyChangeEvent pce) throws PropertyVetoException {
	        BeanContextSupport.this.vetoableChange(pce);
             }
        };
    }

    /**
     * Gets a copy of the this BeanContext's children.
     * @return a copy of the current nested children
     */
    protected final Object[] copyChildren() {
	synchronized(children) { return children.keySet().toArray(); }
    }

    /**
     * Tests to see if two class objects, 
     * or their names are equal.
     * @param first the first object
     * @param second the second object
     * @return true if equal, false if not
     */
    protected static final boolean classEquals(Class first, Class second) {
	return first.equals(second) || first.getName().equals(second.getName());
    }


    /*
     * fields
     */


    /**
     * all accesses to the <code> protected HashMap children </code> field
     * shall be synchronized on that object.
     */
    protected transient HashMap		children;

    private   	        int 		serializable  = 0; // children serializable

    /**
     * all accesses to the <code> protected ArrayList bcmListeners </code> field
     * shall be synchronized on that object.
     */
    protected transient ArrayList	bcmListeners;

    // 

    /**
     * The current locale of this BeanContext.
     */
    protected 		Locale		locale;

    /**
     * A <tt>boolean</tt> indicating if this 
     * instance may now render a GUI.
     */
    protected 		boolean		okToUseGui;


    /**
     * A <tt>boolean</tt> indicating whether or not 
     * this object is currently in design time mode.
     */
    protected 		boolean		designTime;

    /*
     * transient 
     */

    private transient PropertyChangeListener childPCL;

    private transient VetoableChangeListener childVCL;

    private transient boolean		     serializing;
}