/*

 * 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.Beans;

import java.beans.AppletInitializer;

import java.beans.DesignMode;

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.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 Beans.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);