/*
 * Copyright (c) 1995, 2019, Oracle and/or its affiliates. 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package java.awt;

import java.util.Vector;
import java.util.Locale;
import java.util.EventListener;
import java.awt.peer.ListPeer;
import java.awt.event.*;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.IOException;
import javax.accessibility.*;


/**
 * The {@code List} component presents the user with a
 * scrolling list of text items. The list can be set up so that
 * the user can choose either one item or multiple items.
 * <p>
 * For example, the code&nbsp;.&nbsp;.&nbsp;.
 *
 * <hr><blockquote><pre>
 * List lst = new List(4, false);
 * lst.add("Mercury");
 * lst.add("Venus");
 * lst.add("Earth");
 * lst.add("JavaSoft");
 * lst.add("Mars");
 * lst.add("Jupiter");
 * lst.add("Saturn");
 * lst.add("Uranus");
 * lst.add("Neptune");
 * lst.add("Pluto");
 * cnt.add(lst);
 * </pre></blockquote><hr>
 * <p>
 * where {@code cnt} is a container, produces the following
 * scrolling list:
 * <p>
 * <img src="doc-files/List-1.gif"
 * alt="Shows a list containing: Venus, Earth, JavaSoft, and Mars. Javasoft is
 * selected." style="margin: 7px 10px;">
 * <p>
 * If the List allows multiple selections, then clicking on
 * an item that is already selected deselects it. In the preceding
 * example, only one item from the scrolling list can be selected
 * at a time, since the second argument when creating the new scrolling
 * list is {@code false}. If the List does not allow multiple
 * selections, selecting an item causes any other selected item
 * to be deselected.
 * <p>
 * Note that the list in the example shown was created with four visible
 * rows.  Once the list has been created, the number of visible rows
 * cannot be changed.  A default {@code List} is created with
 * four rows, so that {@code lst = new List()} is equivalent to
 * {@code list = new List(4, false)}.
 * <p>
 * Beginning with Java&nbsp;1.1, the Abstract Window Toolkit
 * sends the {@code List} object all mouse, keyboard, and focus events
 * that occur over it. (The old AWT event model is being maintained
 * only for backwards compatibility, and its use is discouraged.)
 * <p>
 * When an item is selected or deselected by the user, AWT sends an instance
 * of {@code ItemEvent} to the list.
 * When the user double-clicks on an item in a scrolling list,
 * AWT sends an instance of {@code ActionEvent} to the
 * list following the item event. AWT also generates an action event
 * when the user presses the return key while an item in the
 * list is selected.
 * <p>
 * If an application wants to perform some action based on an item
 * in this list being selected or activated by the user, it should implement
 * {@code ItemListener} or {@code ActionListener}
 * as appropriate and register the new listener to receive
 * events from this list.
 * <p>
 * For multiple-selection scrolling lists, it is considered a better
 * user interface to use an external gesture (such as clicking on a
 * button) to trigger the action.
 * @author      Sami Shaio
 * @see         java.awt.event.ItemEvent
 * @see         java.awt.event.ItemListener
 * @see         java.awt.event.ActionEvent
 * @see         java.awt.event.ActionListener
 * @since       1.0
 */
public class List extends Component implements ItemSelectable, Accessible {
    /**
     * A vector created to contain items which will become
     * part of the List Component.
     *
     * @serial
     * @see #addItem(String)
     * @see #getItem(int)
     */
    Vector<String>      items = new Vector<>();

    /**
     * This field will represent the number of visible rows in the
     * {@code List} Component.  It is specified only once, and
     * that is when the list component is actually
     * created.  It will never change.
     *
     * @serial
     * @see #getRows()
     */
    int         rows = 0;

    /**
     * {@code multipleMode} is a variable that will
     * be set to {@code true} if a list component is to be set to
     * multiple selection mode, that is where the user can
     * select more than one item in a list at one time.
     * {@code multipleMode} will be set to false if the
     * list component is set to single selection, that is where
     * the user can only select one item on the list at any
     * one time.
     *
     * @serial
     * @see #isMultipleMode()
     * @see #setMultipleMode(boolean)
     */
    boolean     multipleMode = false;

    /**
     * {@code selected} is an array that will contain
     * the indices of items that have been selected.
     *
     * @serial
     * @see #getSelectedIndexes()
     * @see #getSelectedIndex()
     */
    int[]         selected = new int[0];

    /**
     * This variable contains the value that will be used
     * when trying to make a particular list item visible.
     *
     * @serial
     * @see #makeVisible(int)
     */
    int         visibleIndex = -1;

    transient ActionListener actionListener;
    transient ItemListener itemListener;

    private static final String base = "list";
    private static int nameCounter = 0;

    /*
     * JDK 1.1 serialVersionUID
     */
     private static final long serialVersionUID = -3304312411574666869L;

    /**
     * Creates a new scrolling list.
     * By default, there are four visible lines and multiple selections are
     * not allowed.  Note that this is a convenience method for
     * {@code List(0, false)}.  Also note that the number of visible
     * lines in the list cannot be changed after it has been created.
     * @exception HeadlessException if GraphicsEnvironment.isHeadless()
     * returns true.
     * @see java.awt.GraphicsEnvironment#isHeadless
     */
    public List() throws HeadlessException {
        this(0, false);
    }

    /**
     * Creates a new scrolling list initialized with the specified
     * number of visible lines. By default, multiple selections are
     * not allowed.  Note that this is a convenience method for
     * {@code List(rows, false)}.  Also note that the number
     * of visible rows in the list cannot be changed after it has
     * been created.
     * @param       rows the number of items to show.
     * @exception HeadlessException if GraphicsEnvironment.isHeadless()
     * returns true.
     * @see java.awt.GraphicsEnvironment#isHeadless
     * @since       1.1
     */
    public List(int rows) throws HeadlessException {
        this(rows, false);
    }

    /**
     * The default number of visible rows is 4.  A list with
     * zero rows is unusable and unsightly.
     */
    static final int    DEFAULT_VISIBLE_ROWS = 4;

    /**
     * Creates a new scrolling list initialized to display the specified
     * number of rows. Note that if zero rows are specified, then
     * the list will be created with a default of four rows.
     * Also note that the number of visible rows in the list cannot
     * be changed after it has been created.
     * If the value of {@code multipleMode} is
     * {@code true}, then the user can select multiple items from
     * the list. If it is {@code false}, only one item at a time
     * can be selected.
     * @param       rows   the number of items to show.
     * @param       multipleMode   if {@code true},
     *                     then multiple selections are allowed;
     *                     otherwise, only one item can be selected at a time.
     * @exception HeadlessException if GraphicsEnvironment.isHeadless()
     * returns true.
     * @see java.awt.GraphicsEnvironment#isHeadless
     */
    public List(int rows, boolean multipleMode) throws HeadlessException {
        GraphicsEnvironment.checkHeadless();
        this.rows = (rows != 0) ? rows : DEFAULT_VISIBLE_ROWS;
        this.multipleMode = multipleMode;
    }

    /**
     * Construct a name for this component.  Called by
     * {@code getName} when the name is {@code null}.
     */
    String constructComponentName() {
        synchronized (List.class) {
            return base + nameCounter++;
        }
    }

    /**
     * Creates the peer for the list.  The peer allows us to modify the
     * list's appearance without changing its functionality.
     */
    public void addNotify() {
        synchronized (getTreeLock()) {
            if (peer == null)
                peer = getComponentFactory().createList(this);
            super.addNotify();
        }
    }

    /**
     * Removes the peer for this list.  The peer allows us to modify the
     * list's appearance without changing its functionality.
     */
    public void removeNotify() {
        synchronized (getTreeLock()) {
            ListPeer peer = (ListPeer)this.peer;
            if (peer != null) {
                selected = peer.getSelectedIndexes();
            }
            super.removeNotify();
        }
    }

    /**
     * Gets the number of items in the list.
     * @return     the number of items in the list
     * @see        #getItem
     * @since      1.1
     */
    public int getItemCount() {
        return countItems();
    }

    /**
     * Returns the number of items in the list.
     *
     * @return the number of items in the list
     * @deprecated As of JDK version 1.1,
     * replaced by {@code getItemCount()}.
     */
    @Deprecated
    public int countItems() {
        return items.size();
    }

    /**
     * Gets the item associated with the specified index.
     * @return       an item that is associated with
     *                    the specified index
     * @param        index the position of the item
     * @see          #getItemCount
     */
    public String getItem(int index) {
        return getItemImpl(index);
    }

    // NOTE: This method may be called by privileged threads.
    //       We implement this functionality in a package-private method
    //       to insure that it cannot be overridden by client subclasses.
    //       DO NOT INVOKE CLIENT CODE ON THIS THREAD!
    final String getItemImpl(int index) {
        return items.elementAt(index);
    }

    /**
     * Gets the items in the list.
     * @return       a string array containing items of the list
     * @see          #select
     * @see          #deselect
     * @see          #isIndexSelected
     * @since        1.1
     */
    public synchronized String[] getItems() {
        String[] itemCopies = new String[items.size()];
        items.copyInto(itemCopies);
        return itemCopies;
    }

    /**
     * Adds the specified item to the end of scrolling list.
     * @param item the item to be added
     * @since 1.1
     */
    public void add(String item) {
        addItem(item);
    }

    /**
     * Adds the specified item to the end of the list.
     *
     * @param  item the item to be added
     * @deprecated replaced by {@code add(String)}.
     */
    @Deprecated
    public void addItem(String item) {
        addItem(item, -1);
    }

    /**
     * Adds the specified item to the scrolling list
     * at the position indicated by the index.  The index is
     * zero-based.  If the value of the index is less than zero,
     * or if the value of the index is greater than or equal to
     * the number of items in the list, then the item is added
     * to the end of the list.
     * @param       item   the item to be added;
     *              if this parameter is {@code null} then the item is
     *              treated as an empty string, {@code ""}
     * @param       index  the position at which to add the item
     * @since       1.1
     */
    public void add(String item, int index) {
        addItem(item, index);
    }

    /**
     * Adds the specified item to the list
     * at the position indicated by the index.
     *
     * @param  item the item to be added
     * @param  index the position at which to add the item
     * @deprecated replaced by {@code add(String, int)}.
     */
    @Deprecated
    public synchronized void addItem(String item, int index) {
        if (index < -1 || index >= items.size()) {
            index = -1;
        }

        if (item == null) {
            item = "";
        }

        if (index == -1) {
            items.addElement(item);
        } else {
            items.insertElementAt(item, index);
        }

        ListPeer peer = (ListPeer)this.peer;
        if (peer != null) {
            peer.add(item, index);
        }
    }

    /**
     * Replaces the item at the specified index in the scrolling list
     * with the new string.
     * @param       newValue   a new string to replace an existing item
     * @param       index      the position of the item to replace
     * @exception ArrayIndexOutOfBoundsException if {@code index}
     *          is out of range
     */
    public synchronized void replaceItem(String newValue, int index) {
        remove(index);
        add(newValue, index);
    }

    /**
     * Removes all items from this list.
     * @see #remove
     * @see #delItems
     * @since 1.1
     */
    public void removeAll() {
        clear();
    }

    /**
     * @deprecated As of JDK version 1.1,
     * replaced by {@code removeAll()}.
     */
    @Deprecated
    public synchronized void clear() {
        ListPeer peer = (ListPeer)this.peer;
        if (peer != null) {
            peer.removeAll();
        }
        items = new Vector<>();
        selected = new int[0];
    }

    /**
     * Removes the first occurrence of an item from the list.
     * If the specified item is selected, and is the only selected
     * item in the list, the list is set to have no selection.
     * @param        item  the item to remove from the list
     * @exception    IllegalArgumentException
     *                     if the item doesn't exist in the list
     * @since        1.1
     */
    public synchronized void remove(String item) {
        int index = items.indexOf(item);
        if (index < 0) {
            throw new IllegalArgumentException("item " + item +
                                               " not found in list");
        } else {
            remove(index);
        }
    }

    /**
     * Removes the item at the specified position
     * from this scrolling list.
     * If the item with the specified position is selected, and is the
     * only selected item in the list, the list is set to have no selection.
     * @param      position   the index of the item to delete
     * @see        #add(String, int)
     * @since      1.1
     * @exception    ArrayIndexOutOfBoundsException
     *               if the {@code position} is less than 0 or
     *               greater than {@code getItemCount()-1}
     */
    public void remove(int position) {
        delItem(position);
    }

    /**
     * Removes the item at the specified position.
     *
     * @param  position the index of the item to delete
     * @deprecated replaced by {@code remove(String)}
     *             and {@code remove(int)}.
     */
    @Deprecated
    public void delItem(int position) {
        delItems(position, position);
    }

    /**
     * Gets the index of the selected item on the list,
     *
     * @return        the index of the selected item;
     *                if no item is selected, or if multiple items are
     *                selected, {@code -1} is returned.
     * @see           #select
     * @see           #deselect
     * @see           #isIndexSelected
     */
    public synchronized int getSelectedIndex() {
        int[] sel = getSelectedIndexes();
        return (sel.length == 1) ? sel[0] : -1;
    }

    /**
     * Gets the selected indexes on the list.
     *
     * @return        an array of the selected indexes on this scrolling list;
     *                if no item is selected, a zero-length array is returned.
     * @see           #select
     * @see           #deselect
     * @see           #isIndexSelected
     */
    public synchronized int[] getSelectedIndexes() {
        ListPeer peer = (ListPeer)this.peer;
        if (peer != null) {
            selected = peer.getSelectedIndexes();
        }
        return selected.clone();
    }

    /**
     * Gets the selected item on this scrolling list.
     *
     * @return        the selected item on the list;
     *                if no item is selected, or if multiple items are
     *                selected, {@code null} is returned.
     * @see           #select
     * @see           #deselect
     * @see           #isIndexSelected
     */
    public synchronized String getSelectedItem() {
        int index = getSelectedIndex();
        return (index < 0) ? null : getItem(index);
    }

    /**
     * Gets the selected items on this scrolling list.
     *
     * @return        an array of the selected items on this scrolling list;
     *                if no item is selected, a zero-length array is returned.
     * @see           #select
     * @see           #deselect
     * @see           #isIndexSelected
     */
    public synchronized String[] getSelectedItems() {
        int[] sel = getSelectedIndexes();
        String[] str = new String[sel.length];
        for (int i = 0 ; i < sel.length ; i++) {
            str[i] = getItem(sel[i]);
        }
        return str;
    }

    /**
     * Gets the selected items on this scrolling list in an array of Objects.
     * @return        an array of {@code Object}s representing the
     *                selected items on this scrolling list;
     *                if no item is selected, a zero-length array is returned.
     * @see #getSelectedItems
     * @see ItemSelectable
     */
    public Object[] getSelectedObjects() {
        return getSelectedItems();
    }

    /**
     * Selects the item at the specified index in the scrolling list.
     *<p>
     * Note that passing out of range parameters is invalid,
     * and will result in unspecified behavior.
     *
     * <p>Note that this method should be primarily used to
     * initially select an item in this component.
     * Programmatically calling this method will <i>not</i> trigger
     * an {@code ItemEvent}.  The only way to trigger an
     * {@code ItemEvent} is by user interaction.
     *
     * @param        index the position of the item to select
     * @see          #getSelectedItem
     * @see          #deselect
     * @see          #isIndexSelected
     */
    public void select(int index) {
        // Bug #4059614: select can't be synchronized while calling the peer,
        // because it is called from the Window Thread.  It is sufficient to
        // synchronize the code that manipulates 'selected' except for the
        // case where the peer changes.  To handle this case, we simply
        // repeat the selection process.

        ListPeer peer;
        do {
            peer = (ListPeer)this.peer;
            if (peer != null) {
                peer.select(index);
                return;
            }

            synchronized(this)
            {
                boolean alreadySelected = false;

                for (int i = 0 ; i < selected.length ; i++) {
                    if (selected[i] == index) {
                        alreadySelected = true;
                        break;
                    }
                }

                if (!alreadySelected) {
                    if (!multipleMode) {
                        selected = new int[1];
                        selected[0] = index;
                    } else {
                        int[] newsel = new int[selected.length + 1];
                        System.arraycopy(selected, 0, newsel, 0,
                                         selected.length);
                        newsel[selected.length] = index;
                        selected = newsel;
                    }
                }
            }
        } while (peer != this.peer);
    }

    /**
     * Deselects the item at the specified index.
     * <p>
     * Note that passing out of range parameters is invalid,
     * and will result in unspecified behavior.
     * <p>
     * If the item at the specified index is not selected,
     * then the operation is ignored.
     * @param        index the position of the item to deselect
     * @see          #select
     * @see          #getSelectedItem
     * @see          #isIndexSelected
     */
    public synchronized void deselect(int index) {
        ListPeer peer = (ListPeer)this.peer;
        if (peer != null) {
            if (isMultipleMode() || (getSelectedIndex() == index)) {
                peer.deselect(index);
            }
        }

        for (int i = 0 ; i < selected.length ; i++) {
            if (selected[i] == index) {
                int[] newsel = new int[selected.length - 1];
                System.arraycopy(selected, 0, newsel, 0, i);
                System.arraycopy(selected, i+1, newsel, i, selected.length - (i+1));
                selected = newsel;
                return;
            }
        }
    }

    /**
     * Determines if the specified item in this scrolling list is
     * selected.
     * @param      index   the item to be checked
     * @return     {@code true} if the specified item has been
     *                       selected; {@code false} otherwise
     * @see        #select
     * @see        #deselect
     * @since      1.1
     */
    public boolean isIndexSelected(int index) {
        return isSelected(index);
    }

    /**
     * Determines if the specified item in the list is selected.
     *
     * @param  index specifies the item to be checked
     * @return {@code true} if the item is selected; otherwise {@code false}
     * @deprecated As of JDK version 1.1,
     * replaced by {@code isIndexSelected(int)}.
     */
    @Deprecated
    public boolean isSelected(int index) {
        int[] sel = getSelectedIndexes();
        for (int i = 0 ; i < sel.length ; i++) {
            if (sel[i] == index) {
                return true;
            }
        }
        return false;
    }

    /**
     * Gets the number of visible lines in this list.  Note that
     * once the {@code List} has been created, this number
     * will never change.
     * @return     the number of visible lines in this scrolling list
     */
    public int getRows() {
        return rows;
    }

    /**
     * Determines whether this list allows multiple selections.
     *
     * @return     {@code true} if this list allows multiple
     *                 selections; otherwise, {@code false}
     * @see        #setMultipleMode
     * @since      1.1
     */
    public boolean isMultipleMode() {
        return allowsMultipleSelections();
    }

    /**
     * Determines whether this list allows multiple selections.
     *
     * @return {@code true} if this list allows multiple
     *         selections; otherwise {@code false}
     * @deprecated As of JDK version 1.1,
     * replaced by {@code isMultipleMode()}.
     */
    @Deprecated
    public boolean allowsMultipleSelections() {
        return multipleMode;
    }

    /**
     * Sets the flag that determines whether this list
     * allows multiple selections.
     * When the selection mode is changed from multiple-selection to
     * single-selection, the selected items change as follows:
     * If a selected item has the location cursor, only that
     * item will remain selected.  If no selected item has the
     * location cursor, all items will be deselected.
     * @param       b   if {@code true} then multiple selections
     *                      are allowed; otherwise, only one item from
     *                      the list can be selected at once
     * @see         #isMultipleMode
     * @since       1.1
     */
    public void setMultipleMode(boolean b) {
        setMultipleSelections(b);
    }

    /**
     * Enables or disables multiple selection mode for this list.
     *
     * @param  b {@code true} to enable multiple mode, {@code false} otherwise
     * @deprecated As of JDK version 1.1,
     * replaced by {@code setMultipleMode(boolean)}.
     */
    @Deprecated
    public synchronized void setMultipleSelections(boolean b) {
        if (b != multipleMode) {
            multipleMode = b;
            ListPeer peer = (ListPeer)this.peer;
            if (peer != null) {
                peer.setMultipleMode(b);
            }
        }
    }

    /**
     * Gets the index of the item that was last made visible by
     * the method {@code makeVisible}.
     * @return      the index of the item that was last made visible
     * @see         #makeVisible
     */
    public int getVisibleIndex() {
        return visibleIndex;
    }

    /**
     * Makes the item at the specified index visible.
     * @param       index    the position of the item
     * @see         #getVisibleIndex
     */
    public synchronized void makeVisible(int index) {
        visibleIndex = index;
        ListPeer peer = (ListPeer)this.peer;
        if (peer != null) {
            peer.makeVisible(index);
        }
    }

    /**
     * Gets the preferred dimensions for a list with the specified
     * number of rows.
     * @param      rows    number of rows in the list
     * @return     the preferred dimensions for displaying this scrolling list
     *             given that the specified number of rows must be visible
     * @see        java.awt.Component#getPreferredSize
     * @since      1.1
     */
    public Dimension getPreferredSize(int rows) {
        return preferredSize(rows);
    }

    /**
     * Returns the preferred size of this component
     * assuming it has the specified number of rows.
     *
     * @param  rows the number of rows
     * @return the preferred dimensions for displaying this list
     * @deprecated As of JDK version 1.1,
     * replaced by {@code getPreferredSize(int)}.
     */
    @Deprecated
    public Dimension preferredSize(int rows) {
        synchronized (getTreeLock()) {
            ListPeer peer = (ListPeer)this.peer;
            return (peer != null) ?
                       peer.getPreferredSize(rows) :
                       super.preferredSize();
        }
    }

    /**
     * Gets the preferred size of this scrolling list.
     * @return     the preferred dimensions for displaying this scrolling list
     * @see        java.awt.Component#getPreferredSize
     * @since      1.1
     */
    public Dimension getPreferredSize() {
        return preferredSize();
    }

    /**
     * @deprecated As of JDK version 1.1,
     * replaced by {@code getPreferredSize()}.
     */
    @Deprecated
    public Dimension preferredSize() {
        synchronized (getTreeLock()) {
            return (rows > 0) ?
                       preferredSize(rows) :
                       super.preferredSize();
        }
    }

    /**
     * Gets the minimum dimensions for a list with the specified
     * number of rows.
     * @param      rows    number of rows in the list
     * @return     the minimum dimensions for displaying this scrolling list
     *             given that the specified number of rows must be visible
     * @see        java.awt.Component#getMinimumSize
     * @since      1.1
     */
    public Dimension getMinimumSize(int rows) {
        return minimumSize(rows);
    }

    /**
     * Returns the minimum dimensions for the list
     * with the specified number of rows.
     *
     * @param  rows the number of rows in the list
     * @return the minimum dimensions for displaying this list
     * @deprecated As of JDK version 1.1,
     * replaced by {@code getMinimumSize(int)}.
     */
    @Deprecated
    public Dimension minimumSize(int rows) {
        synchronized (getTreeLock()) {
            ListPeer peer = (ListPeer)this.peer;
            return (peer != null) ?
                       peer.getMinimumSize(rows) :
                       super.minimumSize();
        }
    }

    /**
     * Determines the minimum size of this scrolling list.
     * @return       the minimum dimensions needed
     *                        to display this scrolling list
     * @see          java.awt.Component#getMinimumSize()
     * @since        1.1
     */
    public Dimension getMinimumSize() {
        return minimumSize();
    }

    /**
     * @deprecated As of JDK version 1.1,
     * replaced by {@code getMinimumSize()}.
     */
    @Deprecated
    public Dimension minimumSize() {
        synchronized (getTreeLock()) {
            return (rows > 0) ? minimumSize(rows) : super.minimumSize();
        }
    }

    /**
     * Adds the specified item listener to receive item events from
     * this list.  Item events are sent in response to user input, but not
     * in response to calls to {@code select} or {@code deselect}.
     * If listener {@code l} is {@code null},
     * no exception is thrown and no action is performed.
     * <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads"
     * >AWT Threading Issues</a> for details on AWT's threading model.
     *
     * @param         l the item listener
     * @see           #removeItemListener
     * @see           #getItemListeners
     * @see           #select
     * @see           #deselect
     * @see           java.awt.event.ItemEvent
     * @see           java.awt.event.ItemListener
     * @since         1.1
     */
    public synchronized void addItemListener(ItemListener l) {
        if (l == null) {
            return;
        }
        itemListener = AWTEventMulticaster.add(itemListener, l);
        newEventsOnly = true;
    }

    /**
     * Removes the specified item listener so that it no longer
     * receives item events from this list.
     * If listener {@code l} is {@code null},
     * no exception is thrown and no action is performed.
     * <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads"
     * >AWT Threading Issues</a> for details on AWT's threading model.
     *
     * @param           l the item listener
     * @see             #addItemListener
     * @see             #getItemListeners
     * @see             java.awt.event.ItemEvent
     * @see             java.awt.event.ItemListener
     * @since           1.1
     */
    public synchronized void removeItemListener(ItemListener l) {
        if (l == null) {
            return;
        }
        itemListener = AWTEventMulticaster.remove(itemListener, l);
    }

    /**
     * Returns an array of all the item listeners
     * registered on this list.
     *
     * @return all of this list's {@code ItemListener}s
     *         or an empty array if no item
     *         listeners are currently registered
     *
     * @see             #addItemListener
     * @see             #removeItemListener
     * @see             java.awt.event.ItemEvent
     * @see             java.awt.event.ItemListener
     * @since 1.4
     */
    public synchronized ItemListener[] getItemListeners() {
        return getListeners(ItemListener.class);
    }

    /**
     * Adds the specified action listener to receive action events from
     * this list. Action events occur when a user double-clicks
     * on a list item or types Enter when the list has the keyboard
     * focus.
     * <p>
     * If listener {@code l} is {@code null},
     * no exception is thrown and no action is performed.
     * <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads"
     * >AWT Threading Issues</a> for details on AWT's threading model.
     *
     * @param         l the action listener
     * @see           #removeActionListener
     * @see           #getActionListeners
     * @see           java.awt.event.ActionEvent
     * @see           java.awt.event.ActionListener
     * @since         1.1
     */
    public synchronized void addActionListener(ActionListener l) {
        if (l == null) {
            return;
        }
        actionListener = AWTEventMulticaster.add(actionListener, l);
        newEventsOnly = true;
    }

    /**
     * Removes the specified action listener so that it no longer
     * receives action events from this list. Action events
     * occur when a user double-clicks on a list item.
     * If listener {@code l} is {@code null},
     * no exception is thrown and no action is performed.
     * <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads"
     * >AWT Threading Issues</a> for details on AWT's threading model.
     *
     * @param           l     the action listener
     * @see             #addActionListener
     * @see             #getActionListeners
     * @see             java.awt.event.ActionEvent
     * @see             java.awt.event.ActionListener
     * @since           1.1
     */
    public synchronized void removeActionListener(ActionListener l) {
        if (l == null) {
            return;
        }
        actionListener = AWTEventMulticaster.remove(actionListener, l);
    }

    /**
     * Returns an array of all the action listeners
     * registered on this list.
     *
     * @return all of this list's {@code ActionListener}s
     *         or an empty array if no action
     *         listeners are currently registered
     *
     * @see             #addActionListener
     * @see             #removeActionListener
     * @see             java.awt.event.ActionEvent
     * @see             java.awt.event.ActionListener
     * @since 1.4
     */
    public synchronized ActionListener[] getActionListeners() {
        return getListeners(ActionListener.class);
    }

    /**
     * Returns an array of all the objects currently registered
     * as <code><em>Foo</em>Listener</code>s
     * upon this {@code List}.
     * <code><em>Foo</em>Listener</code>s are registered using the
     * <code>add<em>Foo</em>Listener</code> method.
     *
     * <p>
     * You can specify the {@code listenerType} argument
     * with a class literal, such as
     * <code><em>Foo</em>Listener.class</code>.
     * For example, you can query a
     * {@code List l}
     * for its item listeners with the following code:
     *
     * <pre>ItemListener[] ils = (ItemListener[])(l.getListeners(ItemListener.class));</pre>
     *
     * If no such listeners exist, this method returns an empty array.
     *
     * @param listenerType the type of listeners requested; this parameter
     *          should specify an interface that descends from
     *          {@code java.util.EventListener}
     * @return an array of all objects registered as
     *          <code><em>Foo</em>Listener</code>s on this list,
     *          or an empty array if no such
     *          listeners have been added
     * @exception ClassCastException if {@code listenerType}
     *          doesn't specify a class or interface that implements
     *          {@code java.util.EventListener}
     *
     * @see #getItemListeners
     * @since 1.3
     */
    public <T extends EventListener> T[] getListeners(Class<T> listenerType) {
        EventListener l = null;
        if  (listenerType == ActionListener.class) {
            l = actionListener;
        } else if  (listenerType == ItemListener.class) {
            l = itemListener;
        } else {
            return super.getListeners(listenerType);
        }
        return AWTEventMulticaster.getListeners(l, listenerType);
    }

    // REMIND: remove when filtering is done at lower level
    boolean eventEnabled(AWTEvent e) {
        switch(e.id) {
          case ActionEvent.ACTION_PERFORMED:
            if ((eventMask & AWTEvent.ACTION_EVENT_MASK) != 0 ||
                actionListener != null) {
                return true;
            }
            return false;
          case ItemEvent.ITEM_STATE_CHANGED:
            if ((eventMask & AWTEvent.ITEM_EVENT_MASK) != 0 ||
                itemListener != null) {
                return true;
            }
            return false;
          default:
            break;
        }
        return super.eventEnabled(e);
    }

    /**
     * Processes events on this scrolling list. If an event is
     * an instance of {@code ItemEvent}, it invokes the
     * {@code processItemEvent} method. Else, if the
     * event is an instance of {@code ActionEvent},
     * it invokes {@code processActionEvent}.
     * If the event is not an item event or an action event,
     * it invokes {@code processEvent} on the superclass.
     * <p>Note that if the event parameter is {@code null}
     * the behavior is unspecified and may result in an
     * exception.
     *
     * @param        e the event
     * @see          java.awt.event.ActionEvent
     * @see          java.awt.event.ItemEvent
     * @see          #processActionEvent
     * @see          #processItemEvent
     * @since        1.1
     */
    protected void processEvent(AWTEvent e) {
        if (e instanceof ItemEvent) {
            processItemEvent((ItemEvent)e);
            return;
        } else if (e instanceof ActionEvent) {
            processActionEvent((ActionEvent)e);
            return;
        }
        super.processEvent(e);
    }

    /**
     * Processes item events occurring on this list by
     * dispatching them to any registered
     * {@code ItemListener} objects.
     * <p>
     * This method is not called unless item events are
     * enabled for this component. Item events are enabled
     * when one of the following occurs:
     * <ul>
     * <li>An {@code ItemListener} object is registered
     * via {@code addItemListener}.
     * <li>Item events are enabled via {@code enableEvents}.
     * </ul>
     * <p>Note that if the event parameter is {@code null}
     * the behavior is unspecified and may result in an
     * exception.
     *
     * @param       e the item event
     * @see         java.awt.event.ItemEvent
     * @see         java.awt.event.ItemListener
     * @see         #addItemListener
     * @see         java.awt.Component#enableEvents
     * @since       1.1
     */
    protected void processItemEvent(ItemEvent e) {
        ItemListener listener = itemListener;
        if (listener != null) {
            listener.itemStateChanged(e);
        }
    }

    /**
     * Processes action events occurring on this component
     * by dispatching them to any registered
     * {@code ActionListener} objects.
     * <p>
     * This method is not called unless action events are
     * enabled for this component. Action events are enabled
     * when one of the following occurs:
     * <ul>
     * <li>An {@code ActionListener} object is registered
     * via {@code addActionListener}.
     * <li>Action events are enabled via {@code enableEvents}.
     * </ul>
     * <p>Note that if the event parameter is {@code null}
     * the behavior is unspecified and may result in an
     * exception.
     *
     * @param       e the action event
     * @see         java.awt.event.ActionEvent
     * @see         java.awt.event.ActionListener
     * @see         #addActionListener
     * @see         java.awt.Component#enableEvents
     * @since       1.1
     */
    protected void processActionEvent(ActionEvent e) {
        ActionListener listener = actionListener;
        if (listener != null) {
            listener.actionPerformed(e);
        }
    }

    /**
     * Returns the parameter string representing the state of this
     * scrolling list. This string is useful for debugging.
     * @return    the parameter string of this scrolling list
     */
    protected String paramString() {
        return super.paramString() + ",selected=" + getSelectedItem();
    }

    /**
     * Deletes the list items in the specified index range.
     *
     * @param  start the beginning index of the range to delete
     * @param  end the ending index of the range to delete
     * @deprecated As of JDK version 1.1,
     * Not for public use in the future.
     * This method is expected to be retained only as a package
     * private method.
     */
    @Deprecated
    public synchronized void delItems(int start, int end) {
        for (int i = end; i >= start; i--) {
            items.removeElementAt(i);
        }
        ListPeer peer = (ListPeer)this.peer;
        if (peer != null) {
            peer.delItems(start, end);
        }
    }

    /*
     * Serialization support.  Since the value of the selected
     * field isn't necessarily up to date, we sync it up with the
     * peer before serializing.
     */

    /**
     * The {@code List} component's
     * Serialized Data Version.
     *
     * @serial
     */
    private int listSerializedDataVersion = 1;

    /**
     * Writes default serializable fields to stream.  Writes
     * a list of serializable {@code ItemListeners}
     * and {@code ActionListeners} as optional data.
     * The non-serializable listeners are detected and
     * no attempt is made to serialize them.
     *
     * @serialData {@code null} terminated sequence of 0
     *  or more pairs; the pair consists of a {@code String}
     *  and an {@code Object}; the {@code String}
     *  indicates the type of object and is one of the
     *  following:
     *  {@code itemListenerK} indicating an
     *    {@code ItemListener} object;
     *  {@code actionListenerK} indicating an
     *    {@code ActionListener} object
     *
     * @param s the {@code ObjectOutputStream} to write
     * @see AWTEventMulticaster#save(ObjectOutputStream, String, EventListener)
     * @see java.awt.Component#itemListenerK
     * @see java.awt.Component#actionListenerK
     * @see #readObject(ObjectInputStream)
     */
    private void writeObject(ObjectOutputStream s)
      throws IOException
    {
      synchronized (this) {
        ListPeer peer = (ListPeer)this.peer;
        if (peer != null) {
          selected = peer.getSelectedIndexes();
        }
      }
      s.defaultWriteObject();

      AWTEventMulticaster.save(s, itemListenerK, itemListener);
      AWTEventMulticaster.save(s, actionListenerK, actionListener);
      s.writeObject(null);
    }

    /**
     * Reads the {@code ObjectInputStream} and if it
     * isn't {@code null} adds a listener to receive
     * both item events and action events (as specified
     * by the key stored in the stream) fired by the
     * {@code List}.
     * Unrecognized keys or values will be ignored.
     *
     * @param s the {@code ObjectInputStream} to write
     * @exception HeadlessException if
     *   {@code GraphicsEnvironment.isHeadless} returns
     *   {@code true}
     * @see #removeItemListener(ItemListener)
     * @see #addItemListener(ItemListener)
     * @see java.awt.GraphicsEnvironment#isHeadless
     * @see #writeObject(ObjectOutputStream)
     */
    private void readObject(ObjectInputStream s)
      throws ClassNotFoundException, IOException, HeadlessException
    {
      GraphicsEnvironment.checkHeadless();
      s.defaultReadObject();

      Object keyOrNull;
      while(null != (keyOrNull = s.readObject())) {
        String key = ((String)keyOrNull).intern();

        if (itemListenerK == key)
          addItemListener((ItemListener)(s.readObject()));

        else if (actionListenerK == key)
          addActionListener((ActionListener)(s.readObject()));

        else // skip value for unrecognized key
          s.readObject();
      }
    }


/////////////////
// Accessibility support
////////////////


    /**
     * Gets the {@code AccessibleContext} associated with this
     * {@code List}. For lists, the {@code AccessibleContext}
     * takes the form of an {@code AccessibleAWTList}.
     * A new {@code AccessibleAWTList} instance is created, if necessary.
     *
     * @return an {@code AccessibleAWTList} that serves as the
     *         {@code AccessibleContext} of this {@code List}
     * @since 1.3
     */
    public AccessibleContext getAccessibleContext() {
        if (accessibleContext == null) {
            accessibleContext = new AccessibleAWTList();
        }
        return accessibleContext;
    }

    /**
     * This class implements accessibility support for the
     * {@code List} class.  It provides an implementation of the
     * Java Accessibility API appropriate to list user-interface elements.
     * @since 1.3
     */
    protected class AccessibleAWTList extends AccessibleAWTComponent
        implements AccessibleSelection, ItemListener, ActionListener
    {
        /*
         * JDK 1.3 serialVersionUID
         */
        private static final long serialVersionUID = 7924617370136012829L;

        /**
         * Constructs new {@code AccessibleAWTList}
         */
        public AccessibleAWTList() {
            super();
            List.this.addActionListener(this);
            List.this.addItemListener(this);
        }

        public void actionPerformed(ActionEvent event)  {
        }

        public void itemStateChanged(ItemEvent event)  {
        }

        /**
         * Get the state set of this object.
         *
         * @return an instance of AccessibleState containing the current state
         * of the object
         * @see AccessibleState
         */
        public AccessibleStateSet getAccessibleStateSet() {
            AccessibleStateSet states = super.getAccessibleStateSet();
            if (List.this.isMultipleMode())  {
                states.add(AccessibleState.MULTISELECTABLE);
            }
            return states;
        }

        /**
         * Get the role of this object.
         *
         * @return an instance of AccessibleRole describing the role of the
         * object
         * @see AccessibleRole
         */
        public AccessibleRole getAccessibleRole() {
            return AccessibleRole.LIST;
        }

        /**
         * Returns the Accessible child contained at the local coordinate
         * Point, if one exists.
         *
         * @return the Accessible at the specified location, if it exists
         */
        public Accessible getAccessibleAt(Point p) {
            return null; // fredxFIXME Not implemented yet
        }

        /**
         * Returns the number of accessible children in the object.  If all
         * of the children of this object implement Accessible, than this
         * method should return the number of children of this object.
         *
         * @return the number of accessible children in the object.
         */
        public int getAccessibleChildrenCount() {
            return List.this.getItemCount();
        }

        /**
         * Return the nth Accessible child of the object.
         *
         * @param i zero-based index of child
         * @return the nth Accessible child of the object
         */
        public Accessible getAccessibleChild(int i) {
            synchronized(List.this)  {
                if (i >= List.this.getItemCount()) {
                    return null;
                } else {
                    return new AccessibleAWTListChild(List.this, i);
                }
            }
        }

        /**
         * Get the AccessibleSelection associated with this object.  In the
         * implementation of the Java Accessibility API for this class,
         * return this object, which is responsible for implementing the
         * AccessibleSelection interface on behalf of itself.
         *
         * @return this object
         */
        public AccessibleSelection getAccessibleSelection() {
            return this;
        }

    // AccessibleSelection methods

        /**
         * Returns the number of items currently selected.
         * If no items are selected, the return value will be 0.
         *
         * @return the number of items currently selected.
         */
         public int getAccessibleSelectionCount() {
             return List.this.getSelectedIndexes().length;
         }

        /**
         * Returns an Accessible representing the specified selected item
         * in the object.  If there isn't a selection, or there are
         * fewer items selected than the integer passed in, the return
         * value will be null.
         *
         * @param i the zero-based index of selected items
         * @return an Accessible containing the selected item
         */
         public Accessible getAccessibleSelection(int i) {
             synchronized(List.this)  {
                 int len = getAccessibleSelectionCount();
                 if (i < 0 || i >= len) {
                     return null;
                 } else {
                     return getAccessibleChild(List.this.getSelectedIndexes()[i]);
                 }
             }
         }

        /**
         * Returns true if the current child of this object is selected.
         *
         * @param i the zero-based index of the child in this Accessible
         * object.
         * @see AccessibleContext#getAccessibleChild
         */
        public boolean isAccessibleChildSelected(int i) {
            return List.this.isIndexSelected(i);
        }

        /**
         * Adds the specified selected item in the object to the object's
         * selection.  If the object supports multiple selections,
         * the specified item is added to any existing selection, otherwise
         * it replaces any existing selection in the object.  If the
         * specified item is already selected, this method has no effect.
         *
         * @param i the zero-based index of selectable items
         */
         public void addAccessibleSelection(int i) {
             List.this.select(i);
         }

        /**
         * Removes the specified selected item in the object from the object's
         * selection.  If the specified item isn't currently selected, this
         * method has no effect.
         *
         * @param i the zero-based index of selectable items
         */
         public void removeAccessibleSelection(int i) {
             List.this.deselect(i);
         }

        /**
         * Clears the selection in the object, so that nothing in the
         * object is selected.
         */
         public void clearAccessibleSelection() {
             synchronized(List.this)  {
                 int[] selectedIndexes = List.this.getSelectedIndexes();
                 if (selectedIndexes == null)
                     return;
                 for (int i = selectedIndexes.length - 1; i >= 0; i--) {
                     List.this.deselect(selectedIndexes[i]);
                 }
             }
         }

        /**
         * Causes every selected item in the object to be selected
         * if the object supports multiple selections.
         */
         public void selectAllAccessibleSelection() {
             synchronized(List.this)  {
                 for (int i = List.this.getItemCount() - 1; i >= 0; i--) {
                     List.this.select(i);
                 }
             }
         }

       /**
        * This class implements accessibility support for
        * List children.  It provides an implementation of the
        * Java Accessibility API appropriate to list children
        * user-interface elements.
        * @since 1.3
        */
        protected class AccessibleAWTListChild extends AccessibleAWTComponent
            implements Accessible
        {
            /*
             * JDK 1.3 serialVersionUID
             */
            private static final long serialVersionUID = 4412022926028300317L;

        // [[[FIXME]]] need to finish implementing this!!!

            private List parent;
            private int  indexInParent;

            /**
             * Constructs new {@code AccessibleAWTListChild} with the given
             * parent {@code List} and 0-based index of this object in the parent.
             *
             * @param  parent the parent {@code List}
             * @param  indexInParent the index in the parent
             */
            public AccessibleAWTListChild(List parent, int indexInParent)  {
                this.parent = parent;
                this.setAccessibleParent(parent);
                this.indexInParent = indexInParent;
            }

            //
            // required Accessible methods
            //
          /**
           * Gets the AccessibleContext for this object.  In the
           * implementation of the Java Accessibility API for this class,
           * return this object, which acts as its own AccessibleContext.
           *
           * @return this object
           */
            public AccessibleContext getAccessibleContext() {
                return this;
            }

            //
            // required AccessibleContext methods
            //

            /**
             * Get the role of this object.
             *
             * @return an instance of AccessibleRole describing the role of
             * the object
             * @see AccessibleRole
             */
            public AccessibleRole getAccessibleRole() {
                return AccessibleRole.LIST_ITEM;
            }

            /**
             * Get the state set of this object.  The AccessibleStateSet of an
             * object is composed of a set of unique AccessibleState's.  A
             * change in the AccessibleStateSet of an object will cause a
             * PropertyChangeEvent to be fired for the
             * ACCESSIBLE_STATE_PROPERTY property.
             *
             * @return an instance of AccessibleStateSet containing the
             * current state set of the object
             * @see AccessibleStateSet
             * @see AccessibleState
             * @see #addPropertyChangeListener
             */
            public AccessibleStateSet getAccessibleStateSet() {
                AccessibleStateSet states = super.getAccessibleStateSet();
                if (parent.isIndexSelected(indexInParent)) {
                    states.add(AccessibleState.SELECTED);
                }
                return states;
            }

            /**
             * Gets the locale of the component. If the component does not
             * have a locale, then the locale of its parent is returned.
             *
             * @return This component's locale.  If this component does not have
             * a locale, the locale of its parent is returned.
             *
             * @exception IllegalComponentStateException
             * If the Component does not have its own locale and has not yet
             * been added to a containment hierarchy such that the locale can
             * be determined from the containing parent.
             */
            public Locale getLocale() {
                return parent.getLocale();
            }

            /**
             * Get the 0-based index of this object in its accessible parent.
             *
             * @return the 0-based index of this object in its parent; -1 if
             * this object does not have an accessible parent.
             *
             * @see #getAccessibleParent
             * @see #getAccessibleChildrenCount
             * @see #getAccessibleChild
             */
            public int getAccessibleIndexInParent() {
                return indexInParent;
            }

            /**
             * Returns the number of accessible children of the object.
             *
             * @return the number of accessible children of the object.
             */
            public int getAccessibleChildrenCount() {
                return 0;       // list elements can't have children
            }

            /**
             * Return the specified Accessible child of the object.  The
             * Accessible children of an Accessible object are zero-based,
             * so the first child of an Accessible child is at index 0, the
             * second child is at index 1, and so on.
             *
             * @param i zero-based index of child
             * @return the Accessible child of the object
             * @see #getAccessibleChildrenCount
             */
            public Accessible getAccessibleChild(int i) {
                return null;    // list elements can't have children
            }


            //
            // AccessibleComponent delegation to parent List
            //

            /**
             * Get the background color of this object.
             *
             * @return the background color, if supported, of the object;
             * otherwise, null
             * @see #setBackground
             */
            public Color getBackground() {
                return parent.getBackground();
            }

            /**
             * Set the background color of this object.
             *
             * @param c the new Color for the background
             * @see #setBackground
             */
            public void setBackground(Color c) {
                parent.setBackground(c);
            }

            /**
             * Get the foreground color of this object.
             *
             * @return the foreground color, if supported, of the object;
             * otherwise, null
             * @see #setForeground
             */
            public Color getForeground() {
                return parent.getForeground();
            }

            /**
             * Set the foreground color of this object.
             *
             * @param c the new Color for the foreground
             * @see #getForeground
             */
            public void setForeground(Color c) {
                parent.setForeground(c);
            }

            /**
             * Get the Cursor of this object.
             *
             * @return the Cursor, if supported, of the object; otherwise, null
             * @see #setCursor
             */
            public Cursor getCursor() {
                return parent.getCursor();
            }

            /**
             * Set the Cursor of this object.
             * <p>
             * The method may have no visual effect if the Java platform
             * implementation and/or the native system do not support
             * changing the mouse cursor shape.
             * @param cursor the new Cursor for the object
             * @see #getCursor
             */
            public void setCursor(Cursor cursor) {
                parent.setCursor(cursor);
            }

            /**
             * Get the Font of this object.
             *
             * @return the Font,if supported, for the object; otherwise, null
             * @see #setFont
             */
            public Font getFont() {
                return parent.getFont();
            }

            /**
             * Set the Font of this object.
             *
             * @param f the new Font for the object
             * @see #getFont
             */
            public void setFont(Font f) {
                parent.setFont(f);
            }

            /**
             * Get the FontMetrics of this object.
             *
             * @param f the Font
             * @return the FontMetrics, if supported, the object; otherwise, null
             * @see #getFont
             */
            public FontMetrics getFontMetrics(Font f) {
                return parent.getFontMetrics(f);
            }

            /**
             * Determine if the object is enabled.  Objects that are enabled
             * will also have the AccessibleState.ENABLED state set in their
             * AccessibleStateSet.
             *
             * @return true if object is enabled; otherwise, false
             * @see #setEnabled
             * @see AccessibleContext#getAccessibleStateSet
             * @see AccessibleState#ENABLED
             * @see AccessibleStateSet
             */
            public boolean isEnabled() {
                return parent.isEnabled();
            }

            /**
             * Set the enabled state of the object.
             *
             * @param b if true, enables this object; otherwise, disables it
             * @see #isEnabled
             */
            public void setEnabled(boolean b) {
                parent.setEnabled(b);
            }

            /**
             * Determine if the object is visible.  Note: this means that the
             * object intends to be visible; however, it may not be
             * showing on the screen because one of the objects that this object
             * is contained by is currently not visible.  To determine if an
             * object is showing on the screen, use isShowing().
             * <p>Objects that are visible will also have the
             * AccessibleState.VISIBLE state set in their AccessibleStateSet.
             *
             * @return true if object is visible; otherwise, false
             * @see #setVisible
             * @see AccessibleContext#getAccessibleStateSet
             * @see AccessibleState#VISIBLE
             * @see AccessibleStateSet
             */
            public boolean isVisible() {
                // [[[FIXME]]] needs to work like isShowing() below
                return false;
                // return parent.isVisible();
            }

            /**
             * Set the visible state of the object.
             *
             * @param b if true, shows this object; otherwise, hides it
             * @see #isVisible
             */
            public void setVisible(boolean b) {
                // [[[FIXME]]] should scroll to item to make it show!
                parent.setVisible(b);
            }

            /**
             * Determine if the object is showing.  This is determined by
             * checking the visibility of the object and visibility of the
             * object ancestors.
             * Note: this will return true even if the object is obscured
             * by another (for example, it to object is underneath a menu
             * that was pulled down).
             *
             * @return true if object is showing; otherwise, false
             */
            public boolean isShowing() {
                // [[[FIXME]]] only if it's showing!!!
                return false;
                // return parent.isShowing();
            }

            /**
             * Checks whether the specified point is within this object's
             * bounds, where the point's x and y coordinates are defined to
             * be relative to the coordinate system of the object.
             *
             * @param p the Point relative to the coordinate system of the
             * object
             * @return true if object contains Point; otherwise false
             * @see #getBounds
             */
            public boolean contains(Point p) {
                // [[[FIXME]]] - only if p is within the list element!!!
                return false;
                // return parent.contains(p);
            }

            /**
             * Returns the location of the object on the screen.
             *
             * @return location of object on screen; null if this object
             * is not on the screen
             * @see #getBounds
             * @see #getLocation
             */
            public Point getLocationOnScreen() {
                // [[[FIXME]]] sigh
                return null;
            }

            /**
             * Gets the location of the object relative to the parent in the
             * form of a point specifying the object's top-left corner in the
             * screen's coordinate space.
             *
             * @return An instance of Point representing the top-left corner of
             * the object's bounds in the coordinate space of the screen; null
             * if this object or its parent are not on the screen
             * @see #getBounds
             * @see #getLocationOnScreen
             */
            public Point getLocation() {
                // [[[FIXME]]]
                return null;
            }

            /**
             * Sets the location of the object relative to the parent.
             * @param p the new position for the top-left corner
             * @see #getLocation
             */
            public void setLocation(Point p) {
                // [[[FIXME]]] maybe - can simply return as no-op
            }

            /**
             * Gets the bounds of this object in the form of a Rectangle object.
             * The bounds specify this object's width, height, and location
             * relative to its parent.
             *
             * @return A rectangle indicating this component's bounds; null if
             * this object is not on the screen.
             * @see #contains
             */
            public Rectangle getBounds() {
                // [[[FIXME]]]
                return null;
            }

            /**
             * Sets the bounds of this object in the form of a Rectangle
             * object.  The bounds specify this object's width, height, and
             * location relative to its parent.
             *
             * @param r rectangle indicating this component's bounds
             * @see #getBounds
             */
            public void setBounds(Rectangle r) {
                // no-op; not supported
            }

            /**
             * Returns the size of this object in the form of a Dimension
             * object.  The height field of the Dimension object contains this
             * object's height, and the width field of the Dimension object
             * contains this object's width.
             *
             * @return A Dimension object that indicates the size of this
             * component; null if this object is not on the screen
             * @see #setSize
             */
            public Dimension getSize() {
                // [[[FIXME]]]
                return null;
            }

            /**
             * Resizes this object so that it has width and height.
             *
             * @param d - The dimension specifying the new size of the object.
             * @see #getSize
             */
            public void setSize(Dimension d) {
                // not supported; no-op
            }

            /**
             * Returns the {@code Accessible} child, if one exists,
             * contained at the local coordinate {@code Point}.
             *
             * @param p the point relative to the coordinate system of this
             *     object
             * @return the {@code Accessible}, if it exists,
             *     at the specified location; otherwise {@code null}
             */
            public Accessible getAccessibleAt(Point p) {
                return null;    // object cannot have children!
            }

            /**
             * Returns whether this object can accept focus or not.   Objects
             * that can accept focus will also have the
             * {@code AccessibleState.FOCUSABLE} state set in their
             * {@code AccessibleStateSet}.
             *
             * @return true if object can accept focus; otherwise false
             * @see AccessibleContext#getAccessibleStateSet
             * @see AccessibleState#FOCUSABLE
             * @see AccessibleState#FOCUSED
             * @see AccessibleStateSet
             */
            public boolean isFocusTraversable() {
                return false;   // list element cannot receive focus!
            }

            /**
             * Requests focus for this object.  If this object cannot accept
             * focus, nothing will happen.  Otherwise, the object will attempt
             * to take focus.
             * @see #isFocusTraversable
             */
            public void requestFocus() {
                // nothing to do; a no-op
            }

            /**
             * Adds the specified focus listener to receive focus events from
             * this component.
             *
             * @param l the focus listener
             * @see #removeFocusListener
             */
            public void addFocusListener(FocusListener l) {
                // nothing to do; a no-op
            }

            /**
             * Removes the specified focus listener so it no longer receives
             * focus events from this component.
             *
             * @param l the focus listener
             * @see #addFocusListener
             */
            public void removeFocusListener(FocusListener l) {
                // nothing to do; a no-op
            }



        } // inner class AccessibleAWTListChild

    } // inner class AccessibleAWTList

}