/*

 * Copyright 1995-2006 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

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

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

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

 * have any questions.

 */

package java.awt;

import java.awt.peer.FileDialogPeer;

import java.io.FilenameFilter;

import java.io.IOException;

import java.io.ObjectInputStream;

/**

 * The <code>FileDialog</code> class displays a dialog window

 * from which the user can select a file.

 * <p>

 * Since it is a modal dialog, when the application calls

 * its <code>show</code> method to display the dialog,

 * it blocks the rest of the application until the user has

 * chosen a file.

 *

 * @see Window#show

 *

 * @author      Sami Shaio

 * @author      Arthur van Hoff

 * @since       JDK1.0

 */

public class FileDialog extends Dialog {

    /**

     * This constant value indicates that the purpose of the file

     * dialog window is to locate a file from which to read.

     */

    public static final int LOAD = 0;

    /**

     * This constant value indicates that the purpose of the file

     * dialog window is to locate a file to which to write.

     */

    public static final int SAVE = 1;

    /*

     * There are two <code>FileDialog</code> modes: <code>LOAD</code> and

     * <code>SAVE</code>.

     * This integer will represent one or the other.

     * If the mode is not specified it will default to <code>LOAD</code>.

     *

     * @serial

     * @see getMode()

     * @see setMode()

     * @see java.awt.FileDialog#LOAD

     * @see java.awt.FileDialog#SAVE

     */

    int mode;

    /*

     * The string specifying the directory to display

     * in the file dialog.  This variable may be <code>null</code>.

     *

     * @serial

     * @see getDirectory()

     * @see setDirectory()

     */

    String dir;

    /*

     * The string specifying the initial value of the

     * filename text field in the file dialog.

     * This variable may be <code>null</code>.

     *

     * @serial

     * @see getFile()

     * @see setFile()

     */

    String file;

    /*

     * The filter used as the file dialog's filename filter.

     * The file dialog will only be displaying files whose

     * names are accepted by this filter.

     * This variable may be <code>null</code>.

     *

     * @serial

     * @see #getFilenameFilter()

     * @see #setFilenameFilter()

     * @see FileNameFilter

     */

    FilenameFilter filter;

    private static final String base = "filedlg";

    private static int nameCounter = 0;

    /*

     * JDK 1.1 serialVersionUID

     */

     private static final long serialVersionUID = 5035145889651310422L;

    static {

        /* ensure that the necessary native libraries are loaded */

        Toolkit.loadLibraries();

        if (!GraphicsEnvironment.isHeadless()) {

            initIDs();

        }

    }

    /**

     * Initialize JNI field and method IDs for fields that may be

       accessed from C.

     */

    private static native void initIDs();

    /**

     * Creates a file dialog for loading a file.  The title of the

     * file dialog is initially empty.  This is a convenience method for

     * <code>FileDialog(parent, "", LOAD)</code>.

     *

     * @param parent the owner of the dialog

     * @since JDK1.1

     */

    public FileDialog(Frame parent) {

        this(parent, "", LOAD);

    }

    /**

     * Creates a file dialog window with the specified title for loading

     * a file. The files shown are those in the current directory.

     * This is a convenience method for

     * <code>FileDialog(parent, title, LOAD)</code>.

     *

     * @param     parent   the owner of the dialog

     * @param     title    the title of the dialog

     */

    public FileDialog(Frame parent, String title) {

        this(parent, title, LOAD);

    }

    /**

     * Creates a file dialog window with the specified title for loading

     * or saving a file.

     * <p>

     * If the value of <code>mode</code> is <code>LOAD</code>, then the

     * file dialog is finding a file to read, and the files shown are those

     * in the current directory.   If the value of

     * <code>mode</code> is <code>SAVE</code>, the file dialog is finding

     * a place to write a file.

     *

     * @param     parent   the owner of the dialog

     * @param     title   the title of the dialog

     * @param     mode   the mode of the dialog; either

     *          <code>FileDialog.LOAD</code> or <code>FileDialog.SAVE</code>

     * @exception  IllegalArgumentException if an illegal file

     *                 dialog mode is supplied

     * @see       java.awt.FileDialog#LOAD

     * @see       java.awt.FileDialog#SAVE

     */

    public FileDialog(Frame parent, String title, int mode) {

        super(parent, title, true);

        this.setMode(mode);

        setLayout(null);

    }

    /**

     * Creates a file dialog for loading a file.  The title of the

     * file dialog is initially empty.  This is a convenience method for

     * <code>FileDialog(parent, "", LOAD)</code>.

     *

     * @param     parent   the owner of the dialog

     * @exception java.lang.IllegalArgumentException if the <code>parent</code>'s

     *            <code>GraphicsConfiguration</code>

     *            is not from a screen device;

     * @exception java.lang.IllegalArgumentException if <code>parent</code>

     *            is <code>null</code>; this exception is always thrown when

     *            <code>GraphicsEnvironment.isHeadless</code>

     *            returns <code>true</code>

     * @see java.awt.GraphicsEnvironment#isHeadless

     * @since 1.5

     */

    public FileDialog(Dialog parent) {

        this(parent, "", LOAD);

    }

    /**

     * Creates a file dialog window with the specified title for loading

     * a file. The files shown are those in the current directory.

     * This is a convenience method for

     * <code>FileDialog(parent, title, LOAD)</code>.

     *

     * @param     parent   the owner of the dialog

     * @param     title    the title of the dialog; a <code>null</code> value

     *                     will be accepted without causing a

     *                     <code>NullPointerException</code> to be thrown

     * @exception java.lang.IllegalArgumentException if the <code>parent</code>'s

     *            <code>GraphicsConfiguration</code>

     *            is not from a screen device;

     * @exception java.lang.IllegalArgumentException if <code>parent</code>

     *            is <code>null</code>; this exception is always thrown when

     *            <code>GraphicsEnvironment.isHeadless</code>

     *            returns <code>true</code>

     * @see java.awt.GraphicsEnvironment#isHeadless

     * @since     1.5

     */

    public FileDialog(Dialog parent, String title) {

        this(parent, title, LOAD);

    }

    /**

     * Creates a file dialog window with the specified title for loading

     * or saving a file.

     * <p>

     * If the value of <code>mode</code> is <code>LOAD</code>, then the

     * file dialog is finding a file to read, and the files shown are those

     * in the current directory.   If the value of

     * <code>mode</code> is <code>SAVE</code>, the file dialog is finding

     * a place to write a file.

     *

     * @param     parent   the owner of the dialog

     * @param     title    the title of the dialog; a <code>null</code> value

     *                     will be accepted without causing a

     *                     <code>NullPointerException</code> to be thrown

     * @param     mode     the mode of the dialog; either

     *                     <code>FileDialog.LOAD</code> or <code>FileDialog.SAVE</code>

     * @exception java.lang.IllegalArgumentException if an illegal

     *            file dialog mode is supplied;

     * @exception java.lang.IllegalArgumentException if the <code>parent</code>'s

     *            <code>GraphicsConfiguration</code>

     *            is not from a screen device;

     * @exception java.lang.IllegalArgumentException if <code>parent</code>

     *            is <code>null</code>; this exception is always thrown when

     *            <code>GraphicsEnvironment.isHeadless</code>

     *            returns <code>true</code>

     * @see       java.awt.GraphicsEnvironment#isHeadless

     * @see       java.awt.FileDialog#LOAD

     * @see       java.awt.FileDialog#SAVE

     * @since     1.5

     */

    public FileDialog(Dialog parent, String title, int mode) {

        super(parent, title, true);

        this.setMode(mode);

        setLayout(null);

    }

    /**

     * Constructs a name for this component. Called by <code>getName()</code>

     * when the name is <code>null</code>.

     */

    String constructComponentName() {

        synchronized (FileDialog.class) {

            return base + nameCounter++;

        }

    }

    /**

     * Creates the file dialog's peer.  The peer allows us to change the look

     * of the file dialog without changing its functionality.

     */

    public void addNotify() {

        synchronized(getTreeLock()) {

            if (parent != null && parent.getPeer() == null) {

                parent.addNotify();

            }

            if (peer == null)

                peer = getToolkit().createFileDialog(this);

            super.addNotify();

        }

    }

    /**

     * Indicates whether this file dialog box is for loading from a file

     * or for saving to a file.

     *

     * @return   the mode of this file dialog window, either

     *               <code>FileDialog.LOAD</code> or

     *               <code>FileDialog.SAVE</code>

     * @see      java.awt.FileDialog#LOAD

     * @see      java.awt.FileDialog#SAVE

     * @see      java.awt.FileDialog#setMode

     */

    public int getMode() {

        return mode;

    }

    /**

     * Sets the mode of the file dialog.  If <code>mode</code> is not

     * a legal value, an exception will be thrown and <code>mode</code>

     * will not be set.

     *

     * @param      mode  the mode for this file dialog, either

     *                 <code>FileDialog.LOAD</code> or

     *                 <code>FileDialog.SAVE</code>

     * @see        java.awt.FileDialog#LOAD

     * @see        java.awt.FileDialog#SAVE

     * @see        java.awt.FileDialog#getMode

     * @exception  IllegalArgumentException if an illegal file

     *                 dialog mode is supplied

     * @since      JDK1.1

     */

    public void setMode(int mode) {

        switch (mode) {

          case LOAD:

          case SAVE:

            this.mode = mode;

            break;

          default:

            throw new IllegalArgumentException("illegal file dialog mode");

        }

    }

    /**

     * Gets the directory of this file dialog.

     *

     * @return  the (potentially <code>null</code> or invalid)

     *          directory of this <code>FileDialog</code>

     * @see       java.awt.FileDialog#setDirectory

     */

    public String getDirectory() {

        return dir;

    }

    /**

     * Sets the directory of this file dialog window to be the

     * specified directory. Specifying a <code>null</code> or an

     * invalid directory implies an implementation-defined default.

     * This default will not be realized, however, until the user

     * has selected a file. Until this point, <code>getDirectory()</code>

     * will return the value passed into this method.

     * <p>

     * Specifying "" as the directory is exactly equivalent to

     * specifying <code>null</code> as the directory.

     *

     * @param     dir   the specified directory

     * @see       java.awt.FileDialog#getDirectory

     */

    public void setDirectory(String dir) {

        this.dir = (dir != null && dir.equals("")) ? null : dir;

        FileDialogPeer peer = (FileDialogPeer)this.peer;

        if (peer != null) {

            peer.setDirectory(this.dir);

        }

    }

    /**

     * Gets the selected file of this file dialog.  If the user

     * selected <code>CANCEL</code>, the returned file is <code>null</code>.

     *

     * @return    the currently selected file of this file dialog window,

     *                or <code>null</code> if none is selected

     * @see       java.awt.FileDialog#setFile

     */

    public String getFile() {

        return file;

    }

    /**

     * Sets the selected file for this file dialog window to be the

     * specified file. This file becomes the default file if it is set

     * before the file dialog window is first shown.

     * <p>

     * Specifying "" as the file is exactly equivalent to specifying

     * <code>null</code>

     * as the file.

     *

     * @param    file   the file being set

     */

    public void setFile(String file) {

        this.file = (file != null && file.equals("")) ? null : file;

        FileDialogPeer peer = (FileDialogPeer)this.peer;

        if (peer != null) {

            peer.setFile(this.file);

        }

    }

    /**

     * Determines this file dialog's filename filter. A filename filter

     * allows the user to specify which files appear in the file dialog

     * window.  Filename filters do not function in Sun's reference

     * implementation for Microsoft Windows.

     *

     * @return    this file dialog's filename filter

     * @see       java.io.FilenameFilter

     * @see       java.awt.FileDialog#setFilenameFilter

     */

    public FilenameFilter getFilenameFilter() {

        return filter;

    }