cardlayout.java

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/*
 * @(#)CardLayout.java	1.36 05/03/12
 *
 * Copyright  1990-2008 Sun Microsystems, Inc. All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
 * 
 * This program 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. 
 * 
 * This program 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 at /legal/license.txt). 
 * 
 * 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 or visit www.sun.com if you need additional
 * information or have any questions. 
 */

package java.awt;

import java.util.Hashtable;
import java.util.Vector;
import java.util.Enumeration;

import java.io.Serializable;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectStreamField;
import java.io.IOException;

/**
 * A <code>CardLayout</code> object is a layout manager for a
 * container. It treats each component in the container as a card.
 * Only one card is visible at a time, and the container acts as
 * a stack of cards. The first component added to a 
 * <code>CardLayout</code> object is the visible component when the 
 * container is first displayed.
 * <p>
 * The ordering of cards is determined by the container's own internal
 * ordering of its component objects. <code>CardLayout</code>
 * defines a set of methods that allow an application to flip
 * through these cards sequentially, or to show a specified card.
 * The {@link CardLayout#addLayoutComponent}
 * method can be used to associate a string identifier with a given card
 * for fast random access.
 *
 * @version 	1.37 01/23/03
 * @author 	Arthur van Hoff
 * @see         java.awt.Container
 * @since       JDK1.0
 */

public class CardLayout implements LayoutManager2,
				   Serializable {

    private static final long serialVersionUID = -4328196481005934313L;

    /*
     * This creates a Vector to store associated
     * pairs of components and their names.
     * @see java.util.Vector
     */
    Vector vector = new Vector();

    /*
     * A pair of Component and String that represents its name.
     */
    class Card implements Serializable {
        static final long serialVersionUID = 6640330810709497518L;
        public String name;
        public Component comp;
        public Card(String cardName, Component cardComponent) {
            name = cardName;
            comp = cardComponent;
        }
    }

    /*
     * Index of Component currently displayed by CardLayout.
     */
    int currentCard = 0;


    /*
    * A cards horizontal Layout gap (inset). It specifies
    * the space between the left and right edges of a 
    * container and the current component.
    * This should be a non negative Integer.
    * @see getHgap()
    * @see setHgap()
    */
    int hgap;

    /*
    * A cards vertical Layout gap (inset). It specifies
    * the space between the top and bottom edges of a 
    * container and the current component.
    * This should be a non negative Integer.
    * @see getVgap()
    * @see setVgap()
    */
    int vgap;

    /**
     * @serialField tab	        Hashtable
     *      deprectated, for forward compatibility only
     * @serialField hgap        int
     * @serialField vgap        int
     * @serialField vector      Vector
     * @serialField currentCard int
     */
    private static final ObjectStreamField[] serialPersistentFields = { 
	new ObjectStreamField("tab", Hashtable.class), 
        new ObjectStreamField("hgap", Integer.TYPE), 
        new ObjectStreamField("vgap", Integer.TYPE), 
        new ObjectStreamField("vector", Vector.class), 
        new ObjectStreamField("currentCard", Integer.TYPE) 
    };

    /**
     * Creates a new card layout with gaps of size zero.
     */
    public CardLayout() {
	this(0, 0);
    }

    /**
     * Creates a new card layout with the specified horizontal and
     * vertical gaps. The horizontal gaps are placed at the left and
     * right edges. The vertical gaps are placed at the top and bottom
     * edges.
     * @param     hgap   the horizontal gap.
     * @param     vgap   the vertical gap.
     */
    public CardLayout(int hgap, int vgap) {
	this.hgap = hgap;
	this.vgap = vgap;
    }

    /**
     * Gets the horizontal gap between components.
     * @return    the horizontal gap between components.
     * @see       java.awt.CardLayout#setHgap(int)
     * @see       java.awt.CardLayout#getVgap()
     * @since     JDK1.1
     */
    public int getHgap() {
	return hgap;
    }

    /**
     * Sets the horizontal gap between components.
     * @param hgap the horizontal gap between components.
     * @see       java.awt.CardLayout#getHgap()
     * @see       java.awt.CardLayout#setVgap(int)
     * @since     JDK1.1
     */
    public void setHgap(int hgap) {
	this.hgap = hgap;
    }

    /**
     * Gets the vertical gap between components.
     * @return the vertical gap between components.
     * @see       java.awt.CardLayout#setVgap(int)
     * @see       java.awt.CardLayout#getHgap()
     */
    public int getVgap() {
	return vgap;
    }

    /**
     * Sets the vertical gap between components.
     * @param     vgap the vertical gap between components.
     * @see       java.awt.CardLayout#getVgap()
     * @see       java.awt.CardLayout#setHgap(int)
     * @since     JDK1.1
     */
    public void setVgap(int vgap) {
	this.vgap = vgap;
    }

    /**
     * Adds the specified component to this card layout's internal
     * table of names. The object specified by <code>constraints</code>
     * must be a string. The card layout stores this string as a key-value
     * pair that can be used for random access to a particular card.
     * By calling the <code>show</code> method, an application can
     * display the component with the specified name.
     * @param     comp          the component to be added.
     * @param     constraints   a tag that identifies a particular
     *                                        card in the layout.
     * @see       java.awt.CardLayout#show(java.awt.Container, java.lang.String)
     * @exception  IllegalArgumentException  if the constraint is not a string.
     */
    public void addLayoutComponent(Component comp, Object constraints) {
      synchronized (comp.getTreeLock()) {
	if (constraints instanceof String) {
	    addLayoutComponent((String)constraints, comp);
	} else {
	    throw new IllegalArgumentException("cannot add to layout: constraint must be a string");
	}
      }
    }

    /**
     * @deprecated   replaced by
     *      <code>addLayoutComponent(Component, Object)</code>.
     */
    public void addLayoutComponent(String name, Component comp) {
        synchronized (comp.getTreeLock()) {
            if (!vector.isEmpty()) {
                comp.setVisible(false);
            }
            for (int i=0; i < vector.size(); i++) {
                if (((Card)vector.get(i)).name.equals(name)) {
                    ((Card)vector.get(i)).comp = comp;
                    return;
                }
            }
            vector.add(new Card(name, comp));
        }
    }

    /**
     * Removes the specified component from the layout.
     * @param   comp   the component to be removed.
     * @see     java.awt.Container#remove(java.awt.Component)
     * @see     java.awt.Container#removeAll()
     */
    public void removeLayoutComponent(Component comp) {
        synchronized (comp.getTreeLock()) {
            for (int i = 0; i < vector.size(); i++) {
                if (((Card)vector.get(i)).comp == comp) { 
                    // if we remove current component we should show next one
                    if (comp.isVisible() && (comp.getParent() != null)) {
                        next(comp.getParent());
                    }

                    vector.remove(i);

                    // correct currentCard if this is necessary
                    if (currentCard > i) {
                        currentCard--;
                    }
                    break;
                }
            }
        }
    }

    /**
     * Determines the preferred size of the container argument using
     * this card layout.
     * @param   parent the name of the parent container.
     * @return  the preferred dimensions to lay out the subcomponents
     *                of the specified container.
     * @see     java.awt.Container#getPreferredSize
     * @see     java.awt.CardLayout#minimumLayoutSize
     */
    public Dimension preferredLayoutSize(Container parent) {
        synchronized (parent.getTreeLock()) {
            Insets insets = parent.getInsets();
            int ncomponents = parent.getComponentCount();
            int w = 0;
            int h = 0;

            for (int i = 0 ; i < ncomponents ; i++) {
                Component comp = parent.getComponent(i);
                Dimension d = comp.getPreferredSize();
                if (d.width > w) {
                    w = d.width;
                }
                if (d.height > h) {
                    h = d.height;
                }
            }
            return new Dimension(insets.left + insets.right + w + hgap*2,
                                 insets.top + insets.bottom + h + vgap*2);
        }
    }

    /**
     * Calculates the minimum size for the specified panel.
     * @param     parent the name of the parent container
     *                in which to do the layout.
     * @return    the minimum dimensions required to lay out the
     *                subcomponents of the specified container.
     * @see       java.awt.Container#doLayout
     * @see       java.awt.CardLayout#preferredLayoutSize
     */
    public Dimension minimumLayoutSize(Container parent) {
        synchronized (parent.getTreeLock()) {
            Insets insets = parent.getInsets();
            int ncomponents = parent.getComponentCount();
            int w = 0;
            int h = 0;

            for (int i = 0 ; i < ncomponents ; i++) {
                Component comp = parent.getComponent(i);
                Dimension d = comp.getMinimumSize();