/*

  * Copyright 1997-2004 Sun Microsystems, Inc.  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.  Sun designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

  * CA 95054 USA or visit www.sun.com if you need additional information or

  * have any questions.

  */

 package java.beans.beancontext;

 import java.awt.Component;

 import java.awt.Container;

 import java.beans.BeanFactory;

 import java.beans.PropertyChangeEvent;

 import java.beans.PropertyChangeListener;

 import java.beans.VetoableChangeListener;

 import java.beans.PropertyVetoException;

 import java.beans.Visibility;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.ObjectInputStream;

 import java.io.ObjectOutputStream;

 import java.io.Serializable;

 import java.net.URL;

 import java.util.ArrayList;

 import java.util.Collection;

 import java.util.HashMap;

 import java.util.Iterator;

 import java.util.Locale;

 import java.util.Map;

 /**

  * This helper class provides a utility implementation of the

  * java.beans.beancontext.BeanContext interface.

  * </p>

  * <p>

  * Since this class directly implements the BeanContext interface, the class

  * can, and is intended to be used either by subclassing this implementation,

  * or via ad-hoc delegation of an instance of this class from another.

  * </p>

  *

  * @author Laurence P. G. Cable

  * @since 1.2

  */

 public class      BeanContextSupport extends BeanContextChildSupport

        implements BeanContext,

                   Serializable,

                   PropertyChangeListener,

                   VetoableChangeListener {

     // Fix for bug 4282900 to pass JCK regression test

     static final long serialVersionUID = -4879613978649577204L;

     /**

      *

      * Construct a BeanContextSupport instance

      *

      *

      * @param peer      The peer <tt>BeanContext</tt> we are

      *                  supplying an implementation for,

      *                  or <tt>null</tt>

      *                  if this object is its own peer

      * @param lcle      The current Locale for this BeanContext. If

      *                  <tt>lcle</tt> is <tt>null</tt>, the default locale

      *                  is assigned to the <tt>BeanContext</tt> instance.

      * @param dTime     The initial state,

      *                  <tt>true</tt> if in design mode,

      *                  <tt>false</tt> if runtime.

      * @param visible   The initial visibility.

      * @see java.util.Locale#getDefault()

      * @see java.util.Locale#setDefault(java.util.Locale)

      */

     public BeanContextSupport(BeanContext peer, Locale lcle, boolean dTime, boolean visible) {

         super(peer);

         locale          = lcle != null ? lcle : Locale.getDefault();

         designTime      = dTime;

         okToUseGui      = visible;

         initialize();

     }

     /**

      * Create an instance using the specified Locale and design mode.

      *

      * @param peer      The peer <tt>BeanContext</tt> we

      *                  are supplying an implementation for,

      *                  or <tt>null</tt> if this object is its own peer

      * @param lcle      The current Locale for this <tt>BeanContext</tt>. If

      *                  <tt>lcle</tt> is <tt>null</tt>, the default locale

      *                  is assigned to the <tt>BeanContext</tt> instance.

      * @param dtime     The initial state, <tt>true</tt>

      *                  if in design mode,

      *                  <tt>false</tt> if runtime.

      * @see java.util.Locale#getDefault()

      * @see java.util.Locale#setDefault(java.util.Locale)

      */

     public BeanContextSupport(BeanContext peer, Locale lcle, boolean dtime) {

         this (peer, lcle, dtime, true);

     }

     /**

      * Create an instance using the specified locale

      *

      * @param peer      The peer BeanContext we are

      *                  supplying an implementation for,

      *                  or <tt>null</tt> if this object

      *                  is its own peer

      * @param lcle      The current Locale for this

      *                  <tt>BeanContext</tt>. If

      *                  <tt>lcle</tt> is <tt>null</tt>,

      *                  the default locale

      *                  is assigned to the <tt>BeanContext</tt>

      *                  instance.

      * @see java.util.Locale#getDefault()

      * @see java.util.Locale#setDefault(java.util.Locale)

      */

     public BeanContextSupport(BeanContext peer, Locale lcle) {

         this (peer, lcle, false, true);

     }

     /**

      * Create an instance using with a default locale

      *

      * @param peer      The peer <tt>BeanContext</tt> we are

      *                  supplying an implementation for,

      *                  or <tt>null</tt> if this object

      *                  is its own peer

      */

     public BeanContextSupport(BeanContext peer) {

         this (peer, null, false, true);

     }

     /**

      * Create an instance that is not a delegate of another object

      */

     public BeanContextSupport() {

         this (null, null, false, true);

     }

     /**

      * Gets the instance of <tt>BeanContext</tt> that

      * this object is providing the implementation for.

      * @return the BeanContext instance

      */

     public BeanContext getBeanContextPeer() { return (BeanContext)getBeanContextChildPeer(); }

     /**

      * <p>

      * The instantiateChild method is a convenience hook

      * in BeanContext to simplify

      * the task of instantiating a Bean, nested,

      * into a <tt>BeanContext</tt>.

      * </p>

      * <p>

      * The semantics of the beanName parameter are defined by java.beans.Beans.instantate.

      * </p>

      *

      * @param beanName the name of the Bean to instantiate within this BeanContext

      * @throws IOException if there is an I/O error when the bean is being deserialized

      * @throws ClassNotFoundException if the class

      * identified by the beanName parameter is not found

      * @return the new object

      */

     public Object instantiateChild(String beanName)

            throws IOException, ClassNotFoundException {

         BeanContext bc = getBeanContextPeer();

         return BeanFactory.instantiate(bc.getClass().getClassLoader(), beanName, bc);

     }

     /**

      * Gets the number of children currently nested in

      * this BeanContext.

      *

      * @return number of children

      */

     public int size() {

         synchronized(children) {

             return children.size();

         }

     }

     /**

      * Reports whether or not this

      * <tt>BeanContext</tt> is empty.

      * A <tt>BeanContext</tt> is considered

      * empty when it contains zero

      * nested children.

      * @return if there are not children

      */

     public boolean isEmpty() {

         synchronized(children) {

             return children.isEmpty();

         }

     }

     /**

      * Determines whether or not the specified object

      * is currently a child of this <tt>BeanContext</tt>.

      * @param o the Object in question

      * @return if this object is a child

      */

     public boolean contains(Object o) {

         synchronized(children) {

             return children.containsKey(o);

         }

     }

     /**

      * Determines whether or not the specified object

      * is currently a child of this <tt>BeanContext</tt>.

      * @param o the Object in question

      * @return if this object is a child

      */

     public boolean containsKey(Object o) {

         synchronized(children) {

             return children.containsKey(o);

         }

     }

     /**

      * Gets all JavaBean or <tt>BeanContext</tt> instances

      * currently nested in this <tt>BeanContext</tt>.

      * @return an <tt>Iterator</tt> of the nested children

      */

     public Iterator iterator() {

         synchronized(children) {

             return new BCSIterator(children.keySet().iterator());

         }

     }

     /**

      * Gets all JavaBean or <tt>BeanContext</tt>

      * instances currently nested in this BeanContext.

      */

     public Object[] toArray() {

         synchronized(children) {

             return children.keySet().toArray();

         }

     }

     /**

      * Gets an array containing all children of

      * this <tt>BeanContext</tt> that match

      * the types contained in arry.

      * @param arry The array of object

      * types that are of interest.

      * @return an array of children

      */

     public Object[] toArray(Object[] arry) {

         synchronized(children) {

             return children.keySet().toArray(arry);

         }

     }

     /************************************************************************/

     /**

      * protected final subclass that encapsulates an iterator but implements

      * a noop remove() method.

      */

     protected static final class BCSIterator implements Iterator {

         BCSIterator(Iterator i) { super(); src = i; }

         public boolean hasNext() { return src.hasNext(); }

         public Object  next()    { return src.next();    }

         public void    remove()  { /* do nothing */      }

         private Iterator src;

     }

     /************************************************************************/

     /*

      * protected nested class containing per child information, an instance

      * of which is associated with each child in the "children" hashtable.

      * subclasses can extend this class to include their own per-child state.

      *

      * Note that this 'value' is serialized with the corresponding child 'key'

      * when the BeanContextSupport is serialized.

      */

     protected class BCSChild implements Serializable {

     private static final long serialVersionUID = -5815286101609939109L;

         BCSChild(Object bcc, Object peer) {

             super();

             child     = bcc;

             proxyPeer = peer;

         }

         Object  getChild()                  { return child; }

         void    setRemovePending(boolean v) { removePending = v; }

         boolean isRemovePending()           { return removePending; }

         boolean isProxyPeer()               { return proxyPeer != null; }

         Object  getProxyPeer()              { return proxyPeer; }

         /*

          * fields

          */

         private           Object   child;

         private           Object   proxyPeer;

         private transient boolean  removePending;

     }

     /**

      * <p>

      * Subclasses can override this method to insert their own subclass

      * of Child without having to override add() or the other Collection

      * methods that add children to the set.

      * </p>

      *

      * @param targetChild the child to create the Child on behalf of

      * @param peer        the peer if the tragetChild and the peer are related by an implementation of BeanContextProxy

      */

     protected BCSChild createBCSChild(Object targetChild, Object peer) {

         return new BCSChild(targetChild, peer);

     }

     /************************************************************************/

     /**

      * Adds/nests a child within this <tt>BeanContext</tt>.

      * <p>

      * Invoked as a side effect of java.beans.Beans.instantiate().

      * If the child object is not valid for adding then this method

      * throws an IllegalStateException.

      * </p>

      *

      *

      * @param targetChild The child objects to nest

      * within this <tt>BeanContext</tt>

      * @return true if the child was added successfully.

      * @see #validatePendingAdd

      */

     public boolean add(Object targetChild) {

         if (targetChild == null) throw new IllegalArgumentException();

         // The specification requires that we do nothing if the child

         // is already nested herein.

         if (children.containsKey(targetChild)) return false; // test before locking

         synchronized(BeanContext.globalHierarchyLock) {

             if (children.containsKey(targetChild)) return false; // check again

             if (!validatePendingAdd(targetChild)) {

                 throw new IllegalStateException();

             }

             // The specification requires that we invoke setBeanContext() on the

             // newly added child if it implements the java.beans.beancontext.BeanContextChild interface

             BeanContextChild cbcc  = getChildBeanContextChild(targetChild);

             BeanContextChild  bccp = null;

             synchronized(targetChild) {

                 if (targetChild instanceof BeanContextProxy) {

                     bccp = ((BeanContextProxy)targetChild).getBeanContextProxy();

                     if (bccp == null) throw new NullPointerException("BeanContextPeer.getBeanContextProxy()");

                 }

                 BCSChild bcsc  = createBCSChild(targetChild, bccp);

                 BCSChild pbcsc = null;

                 synchronized (children) {

                     children.put(targetChild, bcsc);

                     if (bccp != null) children.put(bccp, pbcsc = createBCSChild(bccp, targetChild));

                 }

                 if (cbcc != null) synchronized(cbcc) {

                     try {

                         cbcc.setBeanContext(getBeanContextPeer());

                     } catch (PropertyVetoException pve) {

                         synchronized (children) {

                             children.remove(targetChild);

                             if (bccp != null) children.remove(bccp);

                         }

                         throw new IllegalStateException();

                     }

                     cbcc.addPropertyChangeListener("beanContext", childPCL);

                     cbcc.addVetoableChangeListener("beanContext", childVCL);

                 }

                 Visibility v = getChildVisibility(targetChild);

                 if (v != null) {

                     if (okToUseGui)

                         v.okToUseGui();

                     else

                         v.dontUseGui();

                 }

                 if (getChildSerializable(targetChild) != null) serializable++;

                 childJustAddedHook(targetChild, bcsc);

                 if (bccp != null) {

                     v = getChildVisibility(bccp);

                     if (v != null) {

                         if (okToUseGui)

                             v.okToUseGui();

                         else

                             v.dontUseGui();

                     }

                     if (getChildSerializable(bccp) != null) serializable++;

                     childJustAddedHook(bccp, pbcsc);

                 }

             }

             // The specification requires that we fire a notification of the change

             fireChildrenAdded(new BeanContextMembershipEvent(getBeanContextPeer(), bccp == null ? new Object[] { targetChild } : new Object[] { targetChild, bccp } ));

         }

         return true;

     }

     /**

      * Removes a child from this BeanContext.  If the child object is not

      * for adding then this method throws an IllegalStateException.

      * @param targetChild The child objects to remove

      * @see #validatePendingRemove

      */

     public boolean remove(Object targetChild) {

         return remove(targetChild, true);

     }

     /**

      * internal remove used when removal caused by

      * unexpected <tt>setBeanContext</tt> or

      * by <tt>remove()</tt> invocation.

      * @param targetChild the JavaBean, BeanContext, or Object to be removed

      * @param callChildSetBC used to indicate that

      * the child should be notified that it is no

      * longer nested in this <tt>BeanContext</tt>.

      */

     protected boolean remove(Object targetChild, boolean callChildSetBC) {

         if (targetChild == null) throw new IllegalArgumentException();

         synchronized(BeanContext.globalHierarchyLock) {

             if (!containsKey(targetChild)) return false;

             if (!validatePendingRemove(targetChild)) {

                 throw new IllegalStateException();

             }

             BCSChild bcsc  = (BCSChild)children.get(targetChild);

             BCSChild pbcsc = null;

             Object   peer  = null;

             // we are required to notify the child that it is no longer nested here if

             // it implements java.beans.beancontext.BeanContextChild

             synchronized(targetChild) {

                 if (callChildSetBC) {

                     BeanContextChild cbcc = getChildBeanContextChild(targetChild);

                     if (cbcc != null) synchronized(cbcc) {

                         cbcc.removePropertyChangeListener("beanContext", childPCL);

                         cbcc.removeVetoableChangeListener("beanContext", childVCL);

                         try {

                             cbcc.setBeanContext(null);

                         } catch (PropertyVetoException pve1) {

                             cbcc.addPropertyChangeListener("beanContext", childPCL);

                             cbcc.addVetoableChangeListener("beanContext", childVCL);

                             throw new IllegalStateException();

                         }

                     }

                 }

                 synchronized (children) {

                     children.remove(targetChild);

                     if (bcsc.isProxyPeer()) {

                         pbcsc = (BCSChild)children.get(peer = bcsc.getProxyPeer());

                         children.remove(peer);

                     }

                 }

                 if (getChildSerializable(targetChild) != null) serializable--;

                 childJustRemovedHook(targetChild, bcsc);

                 if (peer != null) {

                     if (getChildSerializable(peer) != null) serializable--;

                     childJustRemovedHook(peer, pbcsc);

                 }

             }

             fireChildrenRemoved(new BeanContextMembershipEvent(getBeanContextPeer(), peer == null ? new Object[] { targetChild } : new Object[] { targetChild, peer } ));

         }

         return true;

     }

     /**

      * Tests to see if all objects in the

      * specified <tt>Collection</tt> are children of

      * this <tt>BeanContext</tt>.

      * @param c the specified <tt>Collection</tt>

      *

      * @return <tt>true</tt> if all objects

      * in the collection are children of

      * this <tt>BeanContext</tt>, false if not.

      */

     public boolean containsAll(Collection c) {

         synchronized(children) {

             Iterator i = c.iterator();

             while (i.hasNext())

                 if(!contains(i.next()))

                     return false;

             return true;

         }

     }

     /**

      * add Collection to set of Children (Unsupported)

      * implementations must synchronized on the hierarchy lock and "children" protected field

      * @throws UnsupportedOperationException

      */

     public boolean addAll(Collection c) {

         throw new UnsupportedOperationException();

     }

     /**

      * remove all specified children (Unsupported)

      * implementations must synchronized on the hierarchy lock and "children" protected field

      * @throws UnsupportedOperationException

      */

     public boolean removeAll(Collection c) {

         throw new UnsupportedOperationException();

     }

     /**

      * retain only specified children (Unsupported)

      * implementations must synchronized on the hierarchy lock and "children" protected field

      * @throws UnsupportedOperationException

      */

     public boolean retainAll(Collection c) {

         throw new UnsupportedOperationException();

     }

     /**

      * clear the children (Unsupported)

      * implementations must synchronized on the hierarchy lock and "children" protected field

      * @throws UnsupportedOperationException

      */

     public void clear() {

         throw new UnsupportedOperationException();

     }

     /**

      * Adds a BeanContextMembershipListener

      *

      * @param  bcml the BeanContextMembershipListener to add

      * @throws NullPointerException

      */

     public void addBeanContextMembershipListener(BeanContextMembershipListener bcml) {

         if (bcml == null) throw new NullPointerException("listener");

         synchronized(bcmListeners) {

             if (bcmListeners.contains(bcml))

                 return;

             else

                 bcmListeners.add(bcml);

         }

     }

     /**

      * Removes a BeanContextMembershipListener

      *

      * @param  bcml the BeanContextMembershipListener to remove

      * @throws NullPointerException

      */

     public void removeBeanContextMembershipListener(BeanContextMembershipListener bcml) {

         if (bcml == null) throw new NullPointerException("listener");

         synchronized(bcmListeners) {

             if (!bcmListeners.contains(bcml))

                 return;

             else

                 bcmListeners.remove(bcml);

         }

     }

     /**

      * @param name the name of the resource requested.

      * @param bcc  the child object making the request.

      *

      * @return  the requested resource as an InputStream

      * @throws  NullPointerException

      */

     public InputStream getResourceAsStream(String name, BeanContextChild bcc) {

         if (name == null) throw new NullPointerException("name");

         if (bcc  == null) throw new NullPointerException("bcc");

         if (containsKey(bcc)) {

             ClassLoader cl = bcc.getClass().getClassLoader();

             return cl != null ? cl.getResourceAsStream(name)

                               : ClassLoader.getSystemResourceAsStream(name);

         } else throw new IllegalArgumentException("Not a valid child");

     }

     /**

      * @param name the name of the resource requested.

      * @param bcc  the child object making the request.

      *

      * @return the requested resource as an InputStream

      */

     public URL getResource(String name, BeanContextChild bcc) {

         if (name == null) throw new NullPointerException("name");

         if (bcc  == null) throw new NullPointerException("bcc");

         if (containsKey(bcc)) {

             ClassLoader cl = bcc.getClass().getClassLoader();

             return cl != null ? cl.getResource(name)

                               : ClassLoader.getSystemResource(name);

         } else throw new IllegalArgumentException("Not a valid child");

     }

     /**

      * Sets the new design time value for this <tt>BeanContext</tt>.

      * @param dTime the new designTime value

      */

     public synchronized void setDesignTime(boolean dTime) {

         if (designTime != dTime) {

             designTime = dTime;

             firePropertyChange("designMode", Boolean.valueOf(!dTime), Boolean.valueOf(dTime));

         }

     }

     /**

      * Reports whether or not this object is in

      * currently in design time mode.

      * @return <tt>true</tt> if in design time mode,

      * <tt>false</tt> if not

      */

     public synchronized boolean isDesignTime() { return designTime; }

     /**

      * Sets the locale of this BeanContext.

      * @param newLocale the new locale. This method call will have

      *        no effect if newLocale is <CODE>null</CODE>.

      * @throws PropertyVetoException if the new value is rejected

      */

     public synchronized void setLocale(Locale newLocale) throws PropertyVetoException {

         if ((locale != null && !locale.equals(newLocale)) && newLocale != null) {

             Locale old = locale;

             fireVetoableChange("locale", old, newLocale); // throws

             locale = newLocale;

             firePropertyChange("locale", old, newLocale);

         }

     }

     /**

      * Gets the locale for this <tt>BeanContext</tt>.

      *

      * @return the current Locale of the <tt>BeanContext</tt>

      */

     public synchronized Locale getLocale() { return locale; }

     /**

      * <p>

      * This method is typically called from the environment in order to determine

      * if the implementor "needs" a GUI.

      * </p>

      * <p>

      * The algorithm used herein tests the BeanContextPeer, and its current children

      * to determine if they are either Containers, Components, or if they implement

      * Visibility and return needsGui() == true.

      * </p>

      * @return <tt>true</tt> if the implementor needs a GUI

      */

     public synchronized boolean needsGui() {

         BeanContext bc = getBeanContextPeer();

         if (bc != this) {

             if (bc instanceof Visibility) return ((Visibility)bc).needsGui();

             if (bc instanceof Container || bc instanceof Component)

                 return true;

         }

         synchronized(children) {

             for (Iterator i = children.keySet().iterator(); i.hasNext();) {

                 Object c = i.next();

                 try {

                         return ((Visibility)c).needsGui();

                     } catch (ClassCastException cce) {

                         // do nothing ...

                     }

                     if (c instanceof Container || c instanceof Component)

                         return true;

             }

         }

         return false;

     }

     /**

      * notify this instance that it may no longer render a GUI.

      */

     public synchronized void dontUseGui() {

         if (okToUseGui) {

             okToUseGui = false;

             // lets also tell the Children that can that they may not use their GUI's

             synchronized(children) {

                 for (Iterator i = children.keySet().iterator(); i.hasNext();) {

                     Visibility v = getChildVisibility(i.next());

                     if (v != null) v.dontUseGui();

                }

             }

         }

     }

     /**

      * Notify this instance that it may now render a GUI

      */

     public synchronized void okToUseGui() {

         if (!okToUseGui) {

             okToUseGui = true;

             // lets also tell the Children that can that they may use their GUI's

             synchronized(children) {

                 for (Iterator i = children.keySet().iterator(); i.hasNext();) {

                     Visibility v = getChildVisibility(i.next());

                     if (v != null) v.okToUseGui();

                 }

             }

         }

     }

     /**

      * Used to determine if the <tt>BeanContext</tt>

      * child is avoiding using its GUI.

      * @return is this instance avoiding using its GUI?

      * @see Visibility

      */

     public boolean avoidingGui() {

         return !okToUseGui && needsGui();

     }

     /**

      * Is this <tt>BeanContext</tt> in the

      * process of being serialized?

      * @return if this <tt>BeanContext</tt> is

      * currently being serialized

      */

     public boolean isSerializing() { return serializing; }

     /**

      * Returns an iterator of all children

      * of this <tt>BeanContext</tt>.

      * @return an iterator for all the current BCSChild values

      */

     protected Iterator bcsChildren() { synchronized(children) { return children.values().iterator();  } }

     /**

      * called by writeObject after defaultWriteObject() but prior to

      * serialization of currently serializable children.

      *

      * This method may be overridden by subclasses to perform custom

      * serialization of their state prior to this superclass serializing

      * the children.

      *

      * This method should not however be used by subclasses to replace their

      * own implementation (if any) of writeObject().

      */

     protected void bcsPreSerializationHook(ObjectOutputStream oos) throws IOException {

     }

     /**

      * called by readObject after defaultReadObject() but prior to

      * deserialization of any children.

      *

      * This method may be overridden by subclasses to perform custom

      * deserialization of their state prior to this superclass deserializing

      * the children.

      *

      * This method should not however be used by subclasses to replace their

      * own implementation (if any) of readObject().

      */

     protected void bcsPreDeserializationHook(ObjectInputStream ois) throws IOException, ClassNotFoundException {

     }

     /**

      * Called by readObject with the newly deserialized child and BCSChild.

      * @param child the newly deserialized child

      * @param bcsc the newly deserialized BCSChild

      */

     protected void childDeserializedHook(Object child, BCSChild bcsc) {

         synchronized(children) {

             children.put(child, bcsc);

         }

     }

     /**

      * Used by writeObject to serialize a Collection.

      * @param oos the <tt>ObjectOutputStream</tt>

      * to use during serialization

      * @param coll the <tt>Collection</tt> to serialize

      * @throws IOException if serialization failed

      */

     protected final void serialize(ObjectOutputStream oos, Collection coll) throws IOException {

         int      count   = 0;

         Object[] objects = coll.toArray();

         for (int i = 0; i < objects.length; i++) {

             if (objects[i] instanceof Serializable)

                 count++;

             else

                 objects[i] = null;

         }

         oos.writeInt(count); // number of subsequent objects

         for (int i = 0; count > 0; i++) {

             Object o = objects[i];

             if (o != null) {

                 oos.writeObject(o);

                 count--;

             }

         }

     }

     /**

      * used by readObject to deserialize a collection.

      * @param ois the ObjectInputStream to use

      * @param coll the Collection

      */

     protected final void deserialize(ObjectInputStream ois, Collection coll) throws IOException, ClassNotFoundException {

         int count = 0;

         count = ois.readInt();

         while (count-- > 0) {

             coll.add(ois.readObject());

         }

     }

     /**

      * Used to serialize all children of

      * this <tt>BeanContext</tt>.

      * @param oos the <tt>ObjectOutputStream</tt>

      * to use during serialization

      * @throws IOException if serialization failed

      */

     public final void writeChildren(ObjectOutputStream oos) throws IOException {

         if (serializable <= 0) return;

         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;

 }