/*
 * @(#)Container.java	1.181 00/04/06
 *
 * Copyright 1995-2000 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * This software is the proprietary information of Sun Microsystems, Inc.  
 * Use is subject to license terms.
 * 
 */
package java.awt;

import java.io.PrintStream;
import java.io.PrintWriter;
import java.awt.peer.ContainerPeer;
import java.awt.peer.ComponentPeer;
import java.awt.event.ComponentEvent;
import java.awt.event.ContainerEvent;
import java.awt.event.FocusEvent;
import java.awt.event.HierarchyEvent;
import java.awt.event.InputEvent;
import java.awt.event.KeyEvent;
import java.awt.event.MouseEvent;
import java.awt.event.ContainerListener;
import java.util.EventListener;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.IOException;
import java.awt.event.AWTEventListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowListener;
import java.awt.event.WindowEvent;
import java.util.Stack;
import java.util.Vector;
import javax.accessibility.*;
import javax.swing.JRootPane;

import sun.awt.DebugHelper;
import sun.awt.GlobalCursorManager;

/**
 * A generic Abstract Window Toolkit(AWT) container object is a component 
 * that can contain other AWT components.
 * <p>
 * Components added to a container are tracked in a list.  The order
 * of the list will define the components' front-to-back stacking order 
 * within the container.  If no index is specified when adding a
 * component to a container, it will be added to the end of the list
 * (and hence to the bottom of the stacking order).
 * @version 	1.181, 04/06/00
 * @author 	Arthur van Hoff
 * @author 	Sami Shaio
 * @see       java.awt.Container#add(java.awt.Component, int)
 * @see       java.awt.Container#getComponent(int)
 * @see       java.awt.LayoutManager
 * @since     JDK1.0
 */
public class Container extends Component {

    /**
     * The number of components in this container.
     * This value can be null.
     * @serial
     * @see getComponent()
     * @see getComponents()
     * @see getComponentCount()
     */
    int ncomponents;

    /** 
     * The components in this container.
     * @serial
     * @see add()
     * @see getComponents()
     */
    Component component[] = new Component[4];

    /** 
     * Layout manager for this container.
     * @serial
     * @see doLayout()
     * @see setLayout()
     * @see getLayout()
     */
    LayoutManager layoutMgr;

    /**
     * Event router for lightweight components.  If this container
     * is native, this dispatcher takes care of forwarding and 
     * retargeting the events to lightweight components contained
     * (if any).
	 * @serial
     */
    private LightweightDispatcher dispatcher;

    /*
     * Internal, cached size information.
     * @serial
     * @see getMaximumSize()
     * @see getPreferredSize()
     */
    private Dimension maxSize;

    // keeps track of the threads that are printing this component
    private transient Vector printingThreads = new Vector();
    // True if there is at least one thread that's printing this component
    private transient boolean printing = false;

    transient ContainerListener containerListener;

    /* HierarchyListener and HierarchyBoundsListener support */
    transient int listeningChildren;
    transient int listeningBoundsChildren;

    /*
     * JDK 1.1 serialVersionUID 
     */
     private static final long serialVersionUID = 4613797578919906343L;

    private static final DebugHelper dbg = DebugHelper.create(Container.class);

    static {
        /* ensure that the necessary native libraries are loaded */
	Toolkit.loadLibraries();
	initIDs();
    }

    /**
     * Initialize JNI field and method IDs for fields that may be
       called from C.
     */
    private static native void initIDs();

    /**
     * Constructs a new Container. Containers can be extended directly, 
     * but are lightweight in this case and must be contained by a parent
     * somewhere higher up in the component tree that is native.
     * (such as Frame for example).
     */
    public Container() {
    }

    /** 
     * Gets the number of components in this panel.
     * @return    the number of components in this panel.
     * @see       java.awt.Container#getComponent
     * @since     JDK1.1
     */
    public int getComponentCount() {
	return countComponents();
    }

    /** 
     * @deprecated As of JDK version 1.1,
     * replaced by getComponentCount().
     */
    public int countComponents() {
	return ncomponents;
    }

    /** 
     * Gets the nth component in this container.
     * @param      n   the index of the component to get.
     * @return     the n<sup>th</sup> component in this container.
     * @exception  ArrayIndexOutOfBoundsException  
     *                 if the n<sup>th</sup> value does not exist.     
     */
    public Component getComponent(int n) {
	synchronized (getTreeLock()) {
	    if ((n < 0) || (n >= ncomponents)) {
		throw new ArrayIndexOutOfBoundsException("No such child: " + n);
	    }
	    return component[n];
	}
    }

    /**
     * Gets all the components in this container.
     * @return    an array of all the components in this container.     
     */
    public Component[] getComponents() {
	return getComponents_NoClientCode();
    }
    // NOTE: This method may be called by privileged threads.
    //       This functionality is implemented in a package-private method 
    //       to insure that it cannot be overridden by client subclasses. 
    //       DO NOT INVOKE CLIENT CODE ON THIS THREAD!
    final Component[] getComponents_NoClientCode() {
	synchronized (getTreeLock()) {
	    Component list[] = new Component[ncomponents];
	    System.arraycopy(component, 0, list, 0, ncomponents);
	    return list;
	}
    } // getComponents_NoClientCode()

    /**
     * Determines the insets of this container, which indicate the size 
     * of the container's border. 
     * <p>
     * A <code>Frame</code> object, for example, has a top inset that 
     * corresponds to the height of the frame's title bar. 
     * @return    the insets of this container.
     * @see       java.awt.Insets
     * @see       java.awt.LayoutManager
     * @since     JDK1.1
     */
    public Insets getInsets() {
    	return insets();
    }

    /**
     * @deprecated As of JDK version 1.1,
     * replaced by <code>getInsets()</code>.
     */
    public Insets insets() {
	if (this.peer != null && this.peer instanceof ContainerPeer) {
	    ContainerPeer peer = (ContainerPeer)this.peer;
	    return (Insets)peer.insets().clone();
	}
	return new Insets(0, 0, 0, 0);
    }

    /** 
     * Adds the specified component to the end of this container. 
     * @param     comp   the component to be added.
     * @return    the component argument.     
     */
    public Component add(Component comp) {
        addImpl(comp, null, -1);
	return comp;
    }

    /**
     * Adds the specified component to this container.
     * It is strongly advised to use the 1.1 method, add(Component, Object),
     * in place of this method.
     */
    public Component add(String name, Component comp) {
	addImpl(comp, name, -1);
	return comp;
    }

    /** 
     * Adds the specified component to this container at the given 
     * position. 
     * @param     comp   the component to be added.
     * @param     index    the position at which to insert the component, 
     *                   or <code>-1</code> to insert the component at the end.
     * @return    the component <code>comp</code>
     * @see	  #remove
     */
    public Component add(Component comp, int index) {
	addImpl(comp, null, index);
	return comp;
    }

    /**
     * Adds the specified component to the end of this container.
     * Also notifies the layout manager to add the component to 
     * this container's layout using the specified constraints object.
     * @param     comp the component to be added
     * @param     constraints an object expressing 
     *                  layout contraints for this component
     * @see       java.awt.LayoutManager
     * @since     JDK1.1
     */
    public void add(Component comp, Object constraints) {
	addImpl(comp, constraints, -1);
    }

    /**
     * Adds the specified component to this container with the specified
     * constraints at the specified index.  Also notifies the layout 
     * manager to add the component to the this container's layout using 
     * the specified constraints object.
     * @param comp the component to be added
     * @param constraints an object expressing layout contraints for this
     * @param index the position in the container's list at which to insert
     * the component. -1 means insert at the end.
     * component
     * @see #remove
     * @see LayoutManager
     */
    public void add(Component comp, Object constraints, int index) {
       addImpl(comp, constraints, index);
    }

    /**
     * Adds the specified component to this container at the specified
     * index. This method also notifies the layout manager to add 
     * the component to this container's layout using the specified 
     * constraints object.
     * <p>
     * This is the method to override if a program needs to track 
     * every add request to a container. An overriding method should 
     * usually include a call to the superclass's version of the method:
     * <p>
     * <blockquote>
     * <code>super.addImpl(comp, constraints, index)</code>
     * </blockquote>
     * <p>
     * @param     comp       the component to be added.
     * @param     constraints an object expressing layout contraints 
     *                 for this component.
     * @param     index the position in the container's list at which to
     *                 insert the component, where <code>-1</code> 
     *                 means insert at the end.
     * @see       java.awt.Container#add(java.awt.Component)       
     * @see       java.awt.Container#add(java.awt.Component, int)       
     * @see       java.awt.Container#add(java.awt.Component, java.lang.Object)       
     * @see       java.awt.LayoutManager
     * @since     JDK1.1
     */
    protected void addImpl(Component comp, Object constraints, int index) {
	synchronized (getTreeLock()) {
	    /* Check for correct arguments:  index in bounds,
	     * comp cannot be one of this container's parents,
	     * and comp cannot be a window.
	     * comp and container must be on the same GraphicsDevice.
	     * if comp is container, all sub-components must be on
	     * same GraphicsDevice.
	     */
	    GraphicsConfiguration thisGC = this.getGraphicsConfiguration();

	    if (index > ncomponents || (index < 0 && index != -1)) {
		throw new IllegalArgumentException(
			  "illegal component position");
	    }
        if (comp instanceof Container) {
            for (Container cn = this; cn != null; cn=cn.parent) {
                if (cn == comp) {
                throw new IllegalArgumentException(
                      "adding container's parent to itself");
                }
            }
            if (comp instanceof Window) {
                throw new IllegalArgumentException(
                       "adding a window to a container");
            }
        }
        if (thisGC != null) {
            comp.checkGD(thisGC.getDevice().getIDstring());
        }

	    /* Reparent the component and tidy up the tree's state. */
	    if (comp.parent != null) {
		comp.parent.remove(comp);
	    }

	    /* Add component to list; allocate new array if necessary. */
	    if (ncomponents == component.length) {
		Component newcomponents[] = new Component[ncomponents * 2];
		System.arraycopy(component, 0, newcomponents, 0, ncomponents);
		component = newcomponents;
	    }
	    if (index == -1 || index == ncomponents) {
		component[ncomponents++] = comp;
	    } else {
		System.arraycopy(component, index, component,
				 index + 1, ncomponents - index);
		component[index] = comp;
		ncomponents++;
	    }
	    comp.parent = this;

	    adjustListeningChildren(AWTEvent.HIERARCHY_EVENT_MASK, 
	        comp.numListening(AWTEvent.HIERARCHY_EVENT_MASK));
	    adjustListeningChildren(AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK,
		comp.numListening(AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK));

	    if (valid) {
		invalidate();
	    }
	    if (peer != null) {
		comp.addNotify();
	    }
	    
	    /* Notify the layout manager of the added component. */
	    if (layoutMgr != null) {
		if (layoutMgr instanceof LayoutManager2) {
		    ((LayoutManager2)layoutMgr).addLayoutComponent(comp, constraints);
		} else if (constraints instanceof String) {
		    layoutMgr.addLayoutComponent((String)constraints, comp);
		}
	    }
            if (containerListener != null || 
                (eventMask & AWTEvent.CONTAINER_EVENT_MASK) != 0) {
                ContainerEvent e = new ContainerEvent(this, 
                                     ContainerEvent.COMPONENT_ADDED,
                                     comp);
                dispatchEvent(e);
            }

	    comp.createHierarchyEvents(HierarchyEvent.HIERARCHY_CHANGED, comp,
				       this, HierarchyEvent.PARENT_CHANGED);
	    if (peer != null && layoutMgr == null && isVisible()) {
	        GlobalCursorManager.updateCursorImmediately();
	    }
	}
    }

    /**
     * Checks that all Components that this Container contains are on
     * the same GraphicsDevice as this Container.  If not, throws an
     * IllegalArgumentException.
     */
    void checkGD(String stringID) {
		Component tempComp;
		for (int i = 0; i < component.length; i++) {
			tempComp= component[i];
			if (tempComp != null) {
				tempComp.checkGD(stringID);
			}	
		}
    }

    /** 
     * Removes the component, specified by <code>index</code>, 
     * from this container. 
     * @param     index   the index of the component to be removed.
     * @see #add
     * @since JDK1.1
     */
    public void remove(int index) {
	synchronized (getTreeLock()) {
    	    Component comp = component[index];
	    if (peer != null) {
		comp.removeNotify();
	    }
	    if (layoutMgr != null) {
		layoutMgr.removeLayoutComponent(comp);
	    }

	    adjustListeningChildren(AWTEvent.HIERARCHY_EVENT_MASK, 
	        -comp.numListening(AWTEvent.HIERARCHY_EVENT_MASK));
	    adjustListeningChildren(AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK,
		-comp.numListening(AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK));

	    comp.parent = null;
	    System.arraycopy(component, index + 1,
			     component, index,
			     ncomponents - index - 1);
	    component[--ncomponents] = null;

	    if (valid) {
		invalidate();
	    }
            if (containerListener != null ||
                (eventMask & AWTEvent.CONTAINER_EVENT_MASK) != 0) {
                ContainerEvent e = new ContainerEvent(this, 
                                     ContainerEvent.COMPONENT_REMOVED,
                                     comp);
                dispatchEvent(e);
            }

	    comp.createHierarchyEvents(HierarchyEvent.HIERARCHY_CHANGED, comp,
				       this, HierarchyEvent.PARENT_CHANGED);
	    if (peer != null && layoutMgr == null && isVisible()) {
	        GlobalCursorManager.updateCursorImmediately();
	    }
	}
    }

    /** 
     * Removes the specified component from this container.
     * @param comp the component to be removed
     * @see #add
     */
    public void remove(Component comp) {
	synchronized (getTreeLock()) {
	    if (comp.parent == this)  {
    		/* Search backwards, expect that more recent additions
		 * are more likely to be removed.
    	    	 */
		Component component[] = this.component;
		for (int i = ncomponents; --i >= 0; ) {
		    if (component[i] == comp) {
    	    	    	remove(i);
		    }
		}
	    }
	}
    }

    /** 
     * Removes all the components from this container.
     * @see #add
     * @see #remove
     */
    public void removeAll() {
	synchronized (getTreeLock()) {
	    adjustListeningChildren(AWTEvent.HIERARCHY_EVENT_MASK,
                                    -listeningChildren);
	    adjustListeningChildren(AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK,
		                    -listeningBoundsChildren);

	    while (ncomponents > 0) {
		Component comp = component[--ncomponents];
		component[ncomponents] = null;

		if (peer != null) {
		    comp.removeNotify();
		}
		if (layoutMgr != null) {
		    layoutMgr.removeLayoutComponent(comp);
		}
		comp.parent = null;
                if (containerListener != null ||
                   (eventMask & AWTEvent.CONTAINER_EVENT_MASK) != 0) {
                    ContainerEvent e = new ContainerEvent(this, 
                                     ContainerEvent.COMPONENT_REMOVED,
                                     comp);
                    dispatchEvent(e);
                }

		comp.createHierarchyEvents(HierarchyEvent.HIERARCHY_CHANGED,
					   comp, this,
					   HierarchyEvent.PARENT_CHANGED);
	    }
	    if (peer != null && layoutMgr == null && isVisible()) {
	        GlobalCursorManager.updateCursorImmediately();
	    }
	    if (valid) {
		invalidate();
	    }
	}
    }

    // Should only be called while holding tree lock
    int numListening(long mask) {
        int superListening = super.numListening(mask);

        if (mask == AWTEvent.HIERARCHY_EVENT_MASK) {
	    if (dbg.on) {
	        // Verify listeningChildren is correct
	        int sum = 0;
		for (int i = 0; i < ncomponents; i++) {
		    sum += component[i].numListening(mask);
		}
		dbg.assert(listeningChildren == sum);
	    }
	    return listeningChildren + superListening;
	} else if (mask == AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK) {
	    if (dbg.on) {
	        // Verify listeningBoundsChildren is correct
	        int sum = 0;
		for (int i = 0; i < ncomponents; i++) {
		    sum += component[i].numListening(mask);
		}
		dbg.assert(listeningBoundsChildren == sum);
	    }
	    return listeningBoundsChildren + superListening;
	} else {
	    if (dbg.on) {
	        dbg.assert(false);
	    }
	    return superListening;
	}
    }

    // Should only be called while holding tree lock
    void adjustListeningChildren(long mask, int num) {
        if (dbg.on) {
	    dbg.assert(mask == AWTEvent.HIERARCHY_EVENT_MASK ||
		       mask == AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK ||
		       mask == (AWTEvent.HIERARCHY_EVENT_MASK |
				AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK));
	}

        if (num == 0)
	    return;

	if ((mask & AWTEvent.HIERARCHY_EVENT_MASK) != 0) {
	    listeningChildren += num;
	}
	if ((mask & AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK) != 0) {
	    listeningBoundsChildren += num;
	}

	if (parent != null) {
	    parent.adjustListeningChildren(mask, num);
	}
    }

    // Should only be called while holding tree lock
    int createHierarchyEvents(int id, Component changed,
			      Container changedParent, long changeFlags) {
        int listeners = 0;
	switch (id) {
	  case HierarchyEvent.HIERARCHY_CHANGED:
	    listeners = listeningChildren;
	    break;
	  case HierarchyEvent.ANCESTOR_MOVED:
	  case HierarchyEvent.ANCESTOR_RESIZED:
	    if (dbg.on) {
	        dbg.assert(changeFlags == 0);
	    }
	    listeners = listeningBoundsChildren;
	    break;
	  default:
	    if (dbg.on) {
	        dbg.assert(false);
	    }
	    break;
	}

        for (int count = listeners, i = 0; count > 0; i++) {
	    count -= component[i].createHierarchyEvents(id, changed,
							changedParent,
							changeFlags);
	}
	return listeners + 
	    super.createHierarchyEvents(id, changed, changedParent,
					changeFlags);
    }

    void createChildHierarchyEvents(int id, long changeFlags) {
        synchronized (getTreeLock()) {
	    int listeners = 0;
	    switch (id) {
	      case HierarchyEvent.HIERARCHY_CHANGED:
		listeners = listeningChildren;
	        break;
	      case HierarchyEvent.ANCESTOR_MOVED:
	      case HierarchyEvent.ANCESTOR_RESIZED:
		if (dbg.on) {
		    dbg.assert(changeFlags == 0);
		}
		listeners = listeningBoundsChildren;
	        break;
	      default:
		if (dbg.on) {
		    dbg.assert(false);
		}
	        break;
	    }
	  
	    for (int count = listeners, i = 0; count > 0; i++) {
	        count -= component[i].createHierarchyEvents(id, this, parent,
							    changeFlags);
	    }
	}
    }        

    /** 
     * Gets the layout manager for this container.  
     * @see #doLayout
     * @see #setLayout
     */
    public LayoutManager getLayout() {
	return layoutMgr;
    }

    /** 
     * Sets the layout manager for this container.
     * @param mgr the specified layout manager
     * @see #doLayout
     * @see #getLayout
     */
    public void setLayout(LayoutManager mgr) {
	layoutMgr = mgr;
	if (valid) {
	    invalidate();
	}
    }

    /** 
     * Causes this container to lay out its components.  Most programs 
     * should not call this method directly, but should invoke 
     * the <code>validate</code> method instead.
     * @see java.awt.LayoutManager#layoutContainer
     * @see #setLayout
     * @see #validate
     * @since JDK1.1
     */
    public void doLayout() {
	layout();
    }

    /** 
     * @deprecated As of JDK version 1.1,
     * replaced by <code>doLayout()</code>.
     */
    public void layout() {
	LayoutManager layoutMgr = this.layoutMgr;
	if (layoutMgr != null) {
	    layoutMgr.layoutContainer(this);
	}
    }

    /** 
     * Invalidates the container.  The container and all parents
     * above it are marked as needing to be laid out.  This method can
     * be called often, so it needs to execute quickly.
     * @see #validate
     * @see #layout
     * @see LayoutManager
     */
    public void invalidate() {
	if (layoutMgr instanceof LayoutManager2) {
	    LayoutManager2 lm = (LayoutManager2) layoutMgr;
	    lm.invalidateLayout(this);
	}
	super.invalidate();
    }

    /** 
     * Validates this container and all of its subcomponents.
     * <p>
     * AWT uses <code>validate</code> to cause a container to lay out   
     * its subcomponents again after the components it contains
     * have been added to or modified.
     * @see #validate
     * @see Component#invalidate
     */
    public void validate() {
        /* Avoid grabbing lock unless really necessary. */
	if (!valid) {
	    boolean updateCur = false;
	    synchronized (getTreeLock()) {
		if (!valid && peer != null) {
		    ContainerPeer p = null;
		    if (peer instanceof ContainerPeer) {
			p = (ContainerPeer) peer;
		    }
		    if (p != null) {
			p.beginValidate();
		    }
		    validateTree();
		    valid = true;
		    if (p != null) {
			p.endValidate();
			updateCur = isVisible();
		    }
		}
	    }	    
	    if (updateCur) {
		GlobalCursorManager.updateCursorImmediately();
	    }
	}
    }

    /**
     * Recursively descends the container tree and recomputes the
     * layout for any subtrees marked as needing it (those marked as
     * invalid).  Synchronization should be provided by the method
     * that calls this one:  <code>validate</code>.
     */
    protected void validateTree() {
	if (!valid) {
	    doLayout();
            Component component[] = this.component;
	    for (int i = 0 ; i < ncomponents ; ++i) {
		Component comp = component[i];
		if (   (comp instanceof Container) 
	            && !(comp instanceof Window)
		    && !comp.valid) {
		    ((Container)comp).validateTree();
		} else {
		    comp.validate();
		}
	    }
	}
	valid = true;
    }

    /**
     * Recursively descends the container tree and invalidates all
     * contained components.
     */
    void invalidateTree() {
        synchronized (getTreeLock()) {
	    for (int i = 0; i < ncomponents; ++i) {
	        Component comp = component[i];
		if (comp instanceof Container) {
		    ((Container)comp).invalidateTree();
		}
		else {
		    if (comp.valid) {
		        comp.invalidate();
		    }
		}
	    }
	    if (valid) {
	        invalidate();
	    }
	}
    }

    /**
     * Sets the font of this container.
     * @param f The font to become this container's font.
     * @see Component#getFont
     * @since JDK1.0
     */
    public void setFont(Font f) {
        boolean shouldinvalidate = false;

	Font oldfont = getFont();
	super.setFont(f);
	Font newfont = getFont();
	if (newfont != oldfont && (oldfont == null ||
				   !oldfont.equals(newfont))) {
	    invalidateTree();
	}
    }

    /** 
     * Returns the preferred size of this container.  
     * @return    an instance of <code>Dimension</code> that represents 
     *                the preferred size of this container.
     * @see       java.awt.Container#getMinimumSize       
     * @see       java.awt.Container#getLayout
     * @see       java.awt.LayoutManager#preferredLayoutSize(java.awt.Container)
     * @see       java.awt.Component#getPreferredSize
     */
    public Dimension getPreferredSize() {
	return preferredSize();
    }

    /** 
     * @deprecated As of JDK version 1.1,
     * replaced by <code>getPreferredSize()</code>.
     */
    public Dimension preferredSize() {
	/* Avoid grabbing the lock if a reasonable cached size value
	 * is available.
	 */ 
    	Dimension dim = prefSize;
    	if (dim != null && isValid()) {
	    return dim;
	}
	synchronized (getTreeLock()) {
	    prefSize = (layoutMgr != null) ?
			       layoutMgr.preferredLayoutSize(this) :
			       super.preferredSize();
	    
	    return prefSize;
	}
    }

    /** 
     * Returns the minimum size of this container.  
     * @return    an instance of <code>Dimension</code> that represents 
     *                the minimum size of this container.
     * @see       java.awt.Container#getPreferredSize       
     * @see       java.awt.Container#getLayout
     * @see       java.awt.LayoutManager#minimumLayoutSize(java.awt.Container)
     * @see       java.awt.Component#getMinimumSize
     * @since     JDK1.1
     */
    public Dimension getMinimumSize() {
	return minimumSize();
    }

    /** 
     * @deprecated As of JDK version 1.1,
     * replaced by <code>getMinimumSize()</code>.
     */
    public Dimension minimumSize() {
	/* Avoid grabbing the lock if a reasonable cached size value
	 * is available.
	 */ 
    	Dimension dim = minSize;
    	if (dim != null && isValid()) {
	    return dim;
	}
	synchronized (getTreeLock()) {
	    minSize = (layoutMgr != null) ?
		   layoutMgr.minimumLayoutSize(this) :
		   super.minimumSize();
	    return minSize;
	}
    }

    /** 
     * Returns the maximum size of this container.  
     * @see #getPreferredSize
     */
    public Dimension getMaximumSize() {
	/* Avoid grabbing the lock if a reasonable cached size value
	 * is available.
	 */ 
    	Dimension dim = maxSize;
    	if (dim != null && isValid()) {
	    return dim;
	}
	if (layoutMgr instanceof LayoutManager2) {
	    synchronized (getTreeLock()) {
		LayoutManager2 lm = (LayoutManager2) layoutMgr;
		maxSize = lm.maximumLayoutSize(this);
	    }
	} else {
	    maxSize = super.getMaximumSize();
	}
	return maxSize;
    }

    /**
     * Returns the alignment along the x axis.  This specifies how
     * the component would like to be aligned relative to other 
     * components.  The value should be a number between 0 and 1
     * where 0 represents alignment along the origin, 1 is aligned
     * the furthest away from the origin, 0.5 is centered, etc.
     */
    public float getAlignmentX() {
	float xAlign;
	if (layoutMgr instanceof LayoutManager2) {
	    synchronized (getTreeLock()) {
		LayoutManager2 lm = (LayoutManager2) layoutMgr;
		xAlign = lm.getLayoutAlignmentX(this);
	    }
	} else {
	    xAlign = super.getAlignmentX();
	}
	return xAlign;
    }

    /**
     * Returns the alignment along the y axis.  This specifies how
     * the component would like to be aligned relative to other 
     * components.  The value should be a number between 0 and 1
     * where 0 represents alignment along the origin, 1 is aligned
     * the furthest away from the origin, 0.5 is centered, etc.
     */
    public float getAlignmentY() {
	float yAlign;
	if (layoutMgr instanceof LayoutManager2) {
	    synchronized (getTreeLock()) {
		LayoutManager2 lm = (LayoutManager2) layoutMgr;
		yAlign = lm.getLayoutAlignmentY(this);
	    }
	} else {
	    yAlign = super.getAlignmentY();
	}
	return yAlign;
    }

    /** 
     * Paints the container. This forwards the paint to any lightweight
     * components that are children of this container. If this method is
     * reimplemented, super.paint(g) should be called so that lightweight
     * components are properly rendered. If a child component is entirely
     * clipped by the current clipping setting in g, paint() will not be
     * forwarded to that child.
     *
     * @param g the specified Graphics window
     * @see   java.awt.Component#update(java.awt.Graphics)
     */
    public void paint(Graphics g) {
	if (isShowing() &&
	    (!printing ||
	     !printingThreads.contains(Thread.currentThread())) ) {

	    // The container is showing on screen and
	    // this paint() is not called from print().
	    // Paint self and forward the paint to lightweight subcomponents.

	    // super.paint(); -- Don't bother, since it's a NOP.

	    GraphicsCallback.PaintCallback.getInstance().
	        runComponents(component, g, GraphicsCallback.LIGHTWEIGHTS);
	}
    }

    /** 
     * Updates the container.  This forwards the update to any lightweight
     * components that are children of this container.  If this method is
     * reimplemented, super.update(g) should be called so that lightweight
     * components are properly rendered.  If a child component is entirely
     * clipped by the current clipping setting in g, update() will not be
     * forwarded to that child.
     *
     * @param g the specified Graphics window
     * @see   java.awt.Component#update(java.awt.Graphics)
     */
    public void update(Graphics g) {
        if (isShowing()) {
            if (! (peer instanceof java.awt.peer.LightweightPeer)) {
                g.clearRect(0, 0, width, height);
            }
            paint(g);
        }
    }

    /** 
     * Prints the container. This forwards the print to any lightweight
     * components that are children of this container. If this method is
     * reimplemented, super.print(g) should be called so that lightweight
     * components are properly rendered. If a child component is entirely
     * clipped by the current clipping setting in g, print() will not be
     * forwarded to that child.
     *
     * @param g the specified Graphics window
     * @see   java.awt.Component#update(java.awt.Graphics)
     */
    public void print(Graphics g) {
        if (isShowing()) {
	    Thread t = Thread.currentThread();
	    try {
	        printingThreads.addElement(t);
		printing = true;
		super.print(g);  // By default, Component.print() calls paint()
	    } finally {
	        printingThreads.removeElement(t);
		printing = !printingThreads.isEmpty();
	    }

	    GraphicsCallback.PrintCallback.getInstance().
	        runComponents(component, g, GraphicsCallback.LIGHTWEIGHTS);
	}
    }

    /** 
     * Paints each of the components in this container.
     * @param     g   the graphics context.
     * @see       java.awt.Component#paint
     * @see       java.awt.Component#paintAll
     */
    public void paintComponents(Graphics g) {
        if (isShowing()) {
	    GraphicsCallback.PaintAllCallback.getInstance().
	        runComponents(component, g, GraphicsCallback.TWO_PASSES);
	}
    }

    /**
     * Simulates the peer callbacks into java.awt for printing of
     * lightweight Containers.
     * @param     g   the graphics context to use for printing.
     * @see       Component#printAll
     * @see       #printComponents
     */
    void lightweightPaint(Graphics g) {
        super.lightweightPaint(g);
        paintHeavyweightComponents(g);
    }

    /**
     * Prints all the heavyweight subcomponents.
     */
    void paintHeavyweightComponents(Graphics g) {
        if (isShowing()) {
	    GraphicsCallback.PaintHeavyweightComponentsCallback.getInstance().
	        runComponents(component, g, GraphicsCallback.LIGHTWEIGHTS |
                                            GraphicsCallback.HEAVYWEIGHTS);
	}
    }

    /** 
     * Prints each of the components in this container. 
     * @param     g   the graphics context.
     * @see       java.awt.Component#print
     * @see       java.awt.Component#printAll
     */
    public void printComponents(Graphics g) {
        if (isShowing()) {
	    GraphicsCallback.PrintAllCallback.getInstance().
	        runComponents(component, g, GraphicsCallback.TWO_PASSES);
	}
    }

    /**
     * Simulates the peer callbacks into java.awt for printing of
     * lightweight Containers.
     * @param     g   the graphics context to use for printing.
     * @see       Component#printAll
     * @see       #printComponents
     */
    void lightweightPrint(Graphics g) {
        super.lightweightPrint(g);
        printHeavyweightComponents(g);
    }

    /**
     * Prints all the heavyweight subcomponents.
     */
    void printHeavyweightComponents(Graphics g) {
        if (isShowing()) {
	    GraphicsCallback.PrintHeavyweightComponentsCallback.getInstance().
	        runComponents(component, g, GraphicsCallback.LIGHTWEIGHTS |
                                            GraphicsCallback.HEAVYWEIGHTS);
	}
    }

    /**
     * Adds the specified container listener to receive container events
     * from this container.
     * If l is null, no exception is thrown and no action is performed.
     *
     * @param    l the container listener
     */ 
    public synchronized void addContainerListener(ContainerListener l) {
	if (l == null) {
	    return;
	}
	containerListener = AWTEventMulticaster.add(containerListener, l);
        newEventsOnly = true;	
    }

    /**
     * Removes the specified container listener so it no longer receives
     * container events from this container.
     * If l is null, no exception is thrown and no action is performed.
     *
     * @param 	l the container listener
     */ 
    public synchronized void removeContainerListener(ContainerListener l) {
	if (l == null) {
	    return;
	}
	containerListener = AWTEventMulticaster.remove(containerListener, l);
    }

    /**
     * Return an array of all the listeners that were added to the Container
     * with addXXXListener(), where XXX is the name of the <code>listenerType</code>
     * argument.  For example, to get all of the ContainerListener(s) for the
     * given Container <code>c</code>, one would write:
     * <pre>
     * ContainerListener[] cls = (ContainerListener[])(c.getListeners(ContainerListener.class))
     * </pre>
     * If no such listener list exists, then an empty array is returned.
     * 
     * @param    listenerType   Type of listeners requested
     * @return   all of the listeners of the specified type supported by this container
     * @since 1.3
     */
    public EventListener[] getListeners(Class listenerType) { 
	EventListener l = null; 
	if  (listenerType == ContainerListener.class) { 
	    l = containerListener;
	} else {
	    return super.getListeners(listenerType);
	}
	return AWTEventMulticaster.getListeners(l, listenerType);
    }

    // REMIND: remove when filtering is done at lower level
    boolean eventEnabled(AWTEvent e) {
        int id = e.getID();

        if (id == ContainerEvent.COMPONENT_ADDED ||
            id == ContainerEvent.COMPONENT_REMOVED) {
            if ((eventMask & AWTEvent.CONTAINER_EVENT_MASK) != 0 ||
                containerListener != null) {
                return true;
            }
            return false;
        }
        return super.eventEnabled(e);
    }          

    /**
     * Processes events on this container. If the event is a ContainerEvent,
     * it invokes the processContainerEvent method, else it invokes its
     * superclass's processEvent.
     * @param e the event
     */
    protected void processEvent(AWTEvent e) {
        if (e instanceof ContainerEvent) {
            processContainerEvent((ContainerEvent)e);     
            return;
        }
	super.processEvent(e);
    }

    /** 
     * Processes container events occurring on this container by
     * dispatching them to any registered ContainerListener objects.
     * NOTE: This method will not be called unless container events
     * are enabled for this component; this happens when one of the
     * following occurs:
     * a) A ContainerListener object is registered via addContainerListener()
     * b) Container events are enabled via enableEvents()
     * @see Component#enableEvents
     * @param e the container event
     */  
    protected void processContainerEvent(ContainerEvent e) {
        if (containerListener != null) {
            switch(e.getID()) {
              case ContainerEvent.COMPONENT_ADDED:
                containerListener.componentAdded(e);
                break;
              case ContainerEvent.COMPONENT_REMOVED:
                containerListener.componentRemoved(e);
                break;
            }
        }
    }

    /*
     * Dispatches an event to this component or one of its sub components.
     * Create ANCESTOR_RESIZED and ANCESTOR_MOVED events in response to
     * COMPONENT_RESIZED and COMPONENT_MOVED events. We have to do this
     * here instead of in processComponentEvent because ComponentEvents
     * may not be enabled for this Container.
     * @param e the event
     */
    void dispatchEventImpl(AWTEvent e) {
	if ((dispatcher != null) && dispatcher.dispatchEvent(e)) {
	    // event was sent to a lightweight component.  The
	    // native-produced event sent to the native container
	    // must be properly disposed of by the peer, so it 
	    // gets forwarded.  If the native host has been removed
	    // as a result of the sending the lightweight event, 
	    // the peer reference will be null.
	    e.consume();
	    if (peer != null) {
		peer.handleEvent(e);
	    }
	    return;
	}
	super.dispatchEventImpl(e);

	switch (e.getID()) {
	  case ComponentEvent.COMPONENT_RESIZED:
	    createChildHierarchyEvents(HierarchyEvent.ANCESTOR_RESIZED, 0);
	    break;
	  case ComponentEvent.COMPONENT_MOVED:
	    createChildHierarchyEvents(HierarchyEvent.ANCESTOR_MOVED, 0);
	    break;
	  default:
	    break;
	}
    }

    /*
     * Dispatches an event to this component, without trying to forward
     * it to any sub components
     * @param e the event
     */
    void dispatchEventToSelf(AWTEvent e) {
	super.dispatchEventImpl(e);
    }

    /**
     * Fetchs the top-most (deepest) lightweight component that is interested
     * in receiving mouse events.
     */
    Component getMouseEventTarget(int x, int y, boolean includeSelf) {
	int ncomponents = this.ncomponents;
        Component component[] = this.component;
	for (int i = 0 ; i < ncomponents ; i++) {
	    Component comp = component[i];
	    if ((comp != null) && (comp.contains(x - comp.x, y - comp.y)) &&
		(comp.peer instanceof java.awt.peer.LightweightPeer) &&
		(comp.visible == true)) {
		// found a component that intersects the point, see if there is 
		// a deeper possibility.
		if (comp instanceof Container) {
		    Container child = (Container) comp;
		    Component deeper = child.getMouseEventTarget(x - child.x, y - child.y, includeSelf);
		    if (deeper != null) {
			return deeper;
		    }
		} else {
		    if ((comp.mouseListener != null) || 
			((comp.eventMask & AWTEvent.MOUSE_EVENT_MASK) != 0) ||
			(comp.mouseMotionListener != null) ||
			((comp.eventMask & AWTEvent.MOUSE_MOTION_EVENT_MASK) != 0)) {
			// there isn't a deeper target, but this component is a target
			return comp;
		    }
		}
	    }
	}
	
	boolean isPeerOK;
	boolean	isMouseOverMe;
	boolean	isMouseListener;
	boolean	isMotionListener;
	
	isPeerOK = (peer instanceof java.awt.peer.LightweightPeer) || includeSelf;
	isMouseOverMe = contains(x,y);
	isMouseListener = (mouseListener != null) ||
			  ((eventMask & AWTEvent.MOUSE_EVENT_MASK) != 0);
	isMotionListener = (mouseMotionListener != null) ||
			   ((eventMask & AWTEvent.MOUSE_MOTION_EVENT_MASK) != 0);

	// didn't find a child target, return this component if it's a possible target
	if ( isMouseOverMe && isPeerOK && (isMouseListener || isMotionListener) ) {
	    return this;
	}
	// no possible target
	return null;
    }

    /**
     * This is called by lightweight components that want the containing
     * windowed parent to enable some kind of events on their behalf.
     * This is needed for events that are normally only dispatched to 
     * windows to be accepted so that they can be forwarded downward to 
     * the lightweight component that has enabled them.
     */
    void proxyEnableEvents(long events) {
	if (peer instanceof java.awt.peer.LightweightPeer) {
	    // this container is lightweight.... continue sending it
	    // upward.
	  if (parent != null) { parent.proxyEnableEvents(events); }
	} else {
	    // This is a native container, so it needs to host
	    // one of it's children.  If this function is called before
	    // a peer has been created we don't yet have a dispatcher
	    // because it has not yet been determined if this instance
	    // is lightweight.
	    if (dispatcher != null) {
		dispatcher.enableEvents(events);
	    }
	}
    }

    Window getWindow() {
        Container w = this;
        while( !(w instanceof Window) ) {
            w = w.getParent();
        }
        return (Window)w;
    }

    /**
     * This is called by lightweight components that have requested focus.
     * The focus request is propagated upward until a native container is
     * found, at which point the native container requests focus and records
     * the component the host is requesting focus for.
     */
    void proxyRequestFocus(Component c) {
	if (peer instanceof java.awt.peer.LightweightPeer) {
	    // this container is lightweight... continue sending it
	    // upward.
	  if (parent != null) { parent.proxyRequestFocus(c); }
	} else {
	    // This is a windowed container, so record true focus
	    // component and request focus from the native window
	    // if needed.
	    if (dispatcher != null && dispatcher.setFocusRequest(c)) {
                // If the focus is currently somewhere within this Window,
                // call the peer to set focus to this Container.  This way,
                // we avoid activating this Window if it's not currently
                // active.  -fredx, 2-19-98, bug #4111098
                Component window = this;
                while (!(window instanceof Window) && window != null)
                    window = window.getParent();
                if (window != null && ((Window)window).isActive()) {
                    peer.requestFocus();
		}
                Toolkit.getEventQueue().changeKeyEventFocus(this);
	    }
	}
    }

    /**
     * @deprecated As of JDK version 1.1,
     * replaced by <code>dispatchEvent(AWTEvent e)</code>
     */
    public void deliverEvent(Event e) {
	Component comp = getComponentAt(e.x, e.y);
	if ((comp != null) && (comp != this)) {
	    e.translate(-comp.x, -comp.y);
	    comp.deliverEvent(e);
	} else {
	    postEvent(e);
	}
    }

    /**
     * Locates the component that contains the x,y position.  The
     * top-most child component is returned in the case where there
     * is overlap in the components.  This is determined by finding
     * the component closest to the index 0 that claims to contain
     * the given point via Component.contains(), except that Components
     * which have native peers take precedence over those which do not
     * (i.e., lightweight Components).
     *
     * @param x the <i>x</i> coordinate
     * @param y the <i>y</i> coordinate
     * @return null if the component does not contain the position.
     * If there is no child component at the requested point and the 
     * point is within the bounds of the container the container itself 
     * is returned; otherwise the top-most child is returned.
     * @see Component#contains
     * @since JDK1.1
     */
    public Component getComponentAt(int x, int y) {
        return locate(x, y);
    }

    /**
     * @deprecated As of JDK version 1.1,
     * replaced by <code>getComponentAt(int, int)</code>.
     */
    public Component locate(int x, int y) {
	if (!contains(x, y)) {
	    return null;
	}
	synchronized (getTreeLock()) {
	    // Two passes: see comment in sun.awt.SunGraphicsCallback
	    for (int i = 0 ; i < ncomponents ; i++) {
	        Component comp = component[i];
		if (comp != null &&
		    !(comp.peer instanceof java.awt.peer.LightweightPeer)) {
		    if (comp.contains(x - comp.x, y - comp.y)) {
		        return comp;
		    }
		}
	    }
	    for (int i = 0 ; i < ncomponents ; i++) {
	        Component comp = component[i];
		if (comp != null &&
		    comp.peer instanceof java.awt.peer.LightweightPeer) {
		    if (comp.contains(x - comp.x, y - comp.y)) {
		        return comp;
		    }
		}
	    }
	}
	return this;
    }

    /**
     * Gets the component that contains the specified point.
     * @param      p   the point.
     * @return     returns the component that contains the point,
     *                 or <code>null</code> if the component does 
     *                 not contain the point. 
     * @see        java.awt.Component#contains 
     * @since      JDK1.1 
     */
    public Component getComponentAt(Point p) {
	return getComponentAt(p.x, p.y);
    }

    /**
     * Locates the visible child component that contains the specified
     * position.  The top-most child component is returned in the case 
     * where there is overlap in the components.  If the containing child 
     * component is a Container, this method will continue searching for 
     * the deepest nested child component.  Components which are not
     * visible are ignored during the search.<p>
     *
     * The findComponentAt method is different from getComponentAt in
     * that getComponentAt only searches the Container's immediate
     * children; if the containing component is a Container, 
     * findComponentAt will search that child to find a nested component.
     *
     * @param x the <i>x</i> coordinate
     * @param y the <i>y</i> coordinate
     * @return null if the component does not contain the position.
     * If there is no child component at the requested point and the 
     * point is within the bounds of the container the container itself 
     * is returned.
     * @see Component#contains
     * @see getComponentAt
     * @since 1.2
     */
    public Component findComponentAt(int x, int y) {
	synchronized (getTreeLock()) {
	   return findComponentAt(x, y, true, false);
	}
    }

    /**
     * Private version of findComponentAt which has two controllable
     * behaviors. Setting 'ignoreEnabled' to 'false' bypasses disabled
     * Components during the serach. This behavior is used by the
     * lightweight cursor support in sun.awt.GlobalCursorManager.
     * Setting 'ignoreGlassPane' to 'true' bypasses the glass panes owned
     * by any JRootPanes found during the search. This behavior is
     * used by the DnD event targeting code. The cursor and DnD code
     * both call this function directly via native code.
     *
     * The addition of both of these features is temporary, pending the
     * adoption of new, public APIs which export these features (probably
     * in merlin).
     */
    final Component findComponentAt(int x, int y, boolean ignoreEnabled,
				    boolean ignoreGlassPane)
    {
        if (!(contains(x, y) && visible && (ignoreEnabled || enabled))) {
	    return null;
	}
	int ncomponents = this.ncomponents;
	Component component[] = this.component;

	Component glassPane = null;
	if (ignoreGlassPane && (this instanceof JRootPane)) {
	    glassPane = ((JRootPane)this).getGlassPane();
	}

	// Two passes: see comment in sun.awt.SunGraphicsCallback
	for (int i = 0 ; i < ncomponents ; i++) {
	    Component comp = component[i];
	    if (comp != null && comp != glassPane &&
		!(comp.peer instanceof java.awt.peer.LightweightPeer)) {
		if (comp instanceof Container) {
		    comp = ((Container)comp).findComponentAt(x - comp.x,
							     y - comp.y,
							     ignoreEnabled,
							     ignoreGlassPane);
		} else {
		    comp = comp.locate(x - comp.x, y - comp.y);
		}
		if (comp != null && comp.visible &&
		    (ignoreEnabled || comp.enabled))
		{
		    return comp;
		}
	    }
	}
	for (int i = 0 ; i < ncomponents ; i++) {
	    Component comp = component[i];
	    if (comp != null && comp != glassPane &&
		comp.peer instanceof java.awt.peer.LightweightPeer) {
		if (comp instanceof Container) {
		    comp = ((Container)comp).findComponentAt(x - comp.x,
							     y - comp.y,
							     ignoreEnabled,
							     ignoreGlassPane);
		} else {
		    comp = comp.locate(x - comp.x, y - comp.y);
		}
		if (comp != null && comp.visible &&
		    (ignoreEnabled || comp.enabled))
		{
		    return comp;
		}
	    }
	}
	return this;
    }

    /**
     * Locates the visible child component that contains the specified
     * point.  The top-most child component is returned in the case 
     * where there is overlap in the components.  If the containing child 
     * component is a Container, this method will continue searching for 
     * the deepest nested child component.  Components which are not
     * visible are ignored during the search.<p>
     *
     * The findComponentAt method is different from getComponentAt in
     * that getComponentAt only searches the Container's immediate
     * children; if the containing component is a Container, 
     * findComponentAt will search that child to find a nested component.
     *
     * @param      p   the point.
     * @return null if the component does not contain the position.
     * If there is no child component at the requested point and the 
     * point is within the bounds of the container the container itself 
     * is returned.
     * @see Component#contains
     * @see getComponentAt
     * @since 1.2
     */
    public Component findComponentAt(Point p) {
        return findComponentAt(p.x, p.y);
    }

    /** 
     * Makes this Container displayable by connecting it to
     * a native screen resource.  Making a container displayable will
     * cause any of its children to be made displayable.
     * This method is called internally by the toolkit and should
     * not be called directly by programs.
     * @see Component#isDisplayable
     * @see #removeNotify
     */
    public void addNotify() {
        synchronized (getTreeLock()) {
	    // addNotify() on the children may cause proxy event enabling
	    // on this instance, so we first call super.addNotify() and
	    // possibly create an lightweight event dispatcher before calling
	    // addNotify() on the children which may be lightweight.
	    super.addNotify();
	    if (! (peer instanceof java.awt.peer.LightweightPeer)) {
	        dispatcher = new LightweightDispatcher(this);
	    }
	    int ncomponents = this.ncomponents;
            Component component[] = this.component;
	    for (int i = 0 ; i < ncomponents ; i++) {
	        component[i].addNotify();
	    }
        }
    }

    /** 
     * Makes this Container undisplayable by removing its connection
     * to its native screen resource.  Make a container undisplayabl