jdk/src/share/classes/java/awt/FileDialog.java
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     1 /*
       
     2  * Copyright 1995-2006 Sun Microsystems, Inc.  All Rights Reserved.
       
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
       
     4  *
       
     5  * This code is free software; you can redistribute it and/or modify it
       
     6  * under the terms of the GNU General Public License version 2 only, as
       
     7  * published by the Free Software Foundation.  Sun designates this
       
     8  * particular file as subject to the "Classpath" exception as provided
       
     9  * by Sun in the LICENSE file that accompanied this code.
       
    10  *
       
    11  * This code is distributed in the hope that it will be useful, but WITHOUT
       
    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
       
    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
       
    14  * version 2 for more details (a copy is included in the LICENSE file that
       
    15  * accompanied this code).
       
    16  *
       
    17  * You should have received a copy of the GNU General Public License version
       
    18  * 2 along with this work; if not, write to the Free Software Foundation,
       
    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
       
    20  *
       
    21  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
       
    22  * CA 95054 USA or visit www.sun.com if you need additional information or
       
    23  * have any questions.
       
    24  */
       
    25 package java.awt;
       
    26 
       
    27 import java.awt.peer.FileDialogPeer;
       
    28 import java.io.FilenameFilter;
       
    29 import java.io.IOException;
       
    30 import java.io.ObjectInputStream;
       
    31 
       
    32 /**
       
    33  * The <code>FileDialog</code> class displays a dialog window
       
    34  * from which the user can select a file.
       
    35  * <p>
       
    36  * Since it is a modal dialog, when the application calls
       
    37  * its <code>show</code> method to display the dialog,
       
    38  * it blocks the rest of the application until the user has
       
    39  * chosen a file.
       
    40  *
       
    41  * @see Window#show
       
    42  *
       
    43  * @author      Sami Shaio
       
    44  * @author      Arthur van Hoff
       
    45  * @since       JDK1.0
       
    46  */
       
    47 public class FileDialog extends Dialog {
       
    48 
       
    49     /**
       
    50      * This constant value indicates that the purpose of the file
       
    51      * dialog window is to locate a file from which to read.
       
    52      */
       
    53     public static final int LOAD = 0;
       
    54 
       
    55     /**
       
    56      * This constant value indicates that the purpose of the file
       
    57      * dialog window is to locate a file to which to write.
       
    58      */
       
    59     public static final int SAVE = 1;
       
    60 
       
    61     /*
       
    62      * There are two <code>FileDialog</code> modes: <code>LOAD</code> and
       
    63      * <code>SAVE</code>.
       
    64      * This integer will represent one or the other.
       
    65      * If the mode is not specified it will default to <code>LOAD</code>.
       
    66      *
       
    67      * @serial
       
    68      * @see getMode()
       
    69      * @see setMode()
       
    70      * @see java.awt.FileDialog#LOAD
       
    71      * @see java.awt.FileDialog#SAVE
       
    72      */
       
    73     int mode;
       
    74 
       
    75     /*
       
    76      * The string specifying the directory to display
       
    77      * in the file dialog.  This variable may be <code>null</code>.
       
    78      *
       
    79      * @serial
       
    80      * @see getDirectory()
       
    81      * @see setDirectory()
       
    82      */
       
    83     String dir;
       
    84 
       
    85     /*
       
    86      * The string specifying the initial value of the
       
    87      * filename text field in the file dialog.
       
    88      * This variable may be <code>null</code>.
       
    89      *
       
    90      * @serial
       
    91      * @see getFile()
       
    92      * @see setFile()
       
    93      */
       
    94     String file;
       
    95 
       
    96     /*
       
    97      * The filter used as the file dialog's filename filter.
       
    98      * The file dialog will only be displaying files whose
       
    99      * names are accepted by this filter.
       
   100      * This variable may be <code>null</code>.
       
   101      *
       
   102      * @serial
       
   103      * @see #getFilenameFilter()
       
   104      * @see #setFilenameFilter()
       
   105      * @see FileNameFilter
       
   106      */
       
   107     FilenameFilter filter;
       
   108 
       
   109     private static final String base = "filedlg";
       
   110     private static int nameCounter = 0;
       
   111 
       
   112     /*
       
   113      * JDK 1.1 serialVersionUID
       
   114      */
       
   115      private static final long serialVersionUID = 5035145889651310422L;
       
   116 
       
   117 
       
   118     static {
       
   119         /* ensure that the necessary native libraries are loaded */
       
   120         Toolkit.loadLibraries();
       
   121         if (!GraphicsEnvironment.isHeadless()) {
       
   122             initIDs();
       
   123         }
       
   124     }
       
   125 
       
   126     /**
       
   127      * Initialize JNI field and method IDs for fields that may be
       
   128        accessed from C.
       
   129      */
       
   130     private static native void initIDs();
       
   131 
       
   132     /**
       
   133      * Creates a file dialog for loading a file.  The title of the
       
   134      * file dialog is initially empty.  This is a convenience method for
       
   135      * <code>FileDialog(parent, "", LOAD)</code>.
       
   136      *
       
   137      * @param parent the owner of the dialog
       
   138      * @since JDK1.1
       
   139      */
       
   140     public FileDialog(Frame parent) {
       
   141         this(parent, "", LOAD);
       
   142     }
       
   143 
       
   144     /**
       
   145      * Creates a file dialog window with the specified title for loading
       
   146      * a file. The files shown are those in the current directory.
       
   147      * This is a convenience method for
       
   148      * <code>FileDialog(parent, title, LOAD)</code>.
       
   149      *
       
   150      * @param     parent   the owner of the dialog
       
   151      * @param     title    the title of the dialog
       
   152      */
       
   153     public FileDialog(Frame parent, String title) {
       
   154         this(parent, title, LOAD);
       
   155     }
       
   156 
       
   157     /**
       
   158      * Creates a file dialog window with the specified title for loading
       
   159      * or saving a file.
       
   160      * <p>
       
   161      * If the value of <code>mode</code> is <code>LOAD</code>, then the
       
   162      * file dialog is finding a file to read, and the files shown are those
       
   163      * in the current directory.   If the value of
       
   164      * <code>mode</code> is <code>SAVE</code>, the file dialog is finding
       
   165      * a place to write a file.
       
   166      *
       
   167      * @param     parent   the owner of the dialog
       
   168      * @param     title   the title of the dialog
       
   169      * @param     mode   the mode of the dialog; either
       
   170      *          <code>FileDialog.LOAD</code> or <code>FileDialog.SAVE</code>
       
   171      * @exception  IllegalArgumentException if an illegal file
       
   172      *                 dialog mode is supplied
       
   173      * @see       java.awt.FileDialog#LOAD
       
   174      * @see       java.awt.FileDialog#SAVE
       
   175      */
       
   176     public FileDialog(Frame parent, String title, int mode) {
       
   177         super(parent, title, true);
       
   178         this.setMode(mode);
       
   179         setLayout(null);
       
   180     }
       
   181 
       
   182     /**
       
   183      * Creates a file dialog for loading a file.  The title of the
       
   184      * file dialog is initially empty.  This is a convenience method for
       
   185      * <code>FileDialog(parent, "", LOAD)</code>.
       
   186      *
       
   187      * @param     parent   the owner of the dialog
       
   188      * @exception java.lang.IllegalArgumentException if the <code>parent</code>'s
       
   189      *            <code>GraphicsConfiguration</code>
       
   190      *            is not from a screen device;
       
   191      * @exception java.lang.IllegalArgumentException if <code>parent</code>
       
   192      *            is <code>null</code>; this exception is always thrown when
       
   193      *            <code>GraphicsEnvironment.isHeadless</code>
       
   194      *            returns <code>true</code>
       
   195      * @see java.awt.GraphicsEnvironment#isHeadless
       
   196      * @since 1.5
       
   197      */
       
   198     public FileDialog(Dialog parent) {
       
   199         this(parent, "", LOAD);
       
   200     }
       
   201 
       
   202     /**
       
   203      * Creates a file dialog window with the specified title for loading
       
   204      * a file. The files shown are those in the current directory.
       
   205      * This is a convenience method for
       
   206      * <code>FileDialog(parent, title, LOAD)</code>.
       
   207      *
       
   208      * @param     parent   the owner of the dialog
       
   209      * @param     title    the title of the dialog; a <code>null</code> value
       
   210      *                     will be accepted without causing a
       
   211      *                     <code>NullPointerException</code> to be thrown
       
   212      * @exception java.lang.IllegalArgumentException if the <code>parent</code>'s
       
   213      *            <code>GraphicsConfiguration</code>
       
   214      *            is not from a screen device;
       
   215      * @exception java.lang.IllegalArgumentException if <code>parent</code>
       
   216      *            is <code>null</code>; this exception is always thrown when
       
   217      *            <code>GraphicsEnvironment.isHeadless</code>
       
   218      *            returns <code>true</code>
       
   219      * @see java.awt.GraphicsEnvironment#isHeadless
       
   220      * @since     1.5
       
   221      */
       
   222     public FileDialog(Dialog parent, String title) {
       
   223         this(parent, title, LOAD);
       
   224     }
       
   225 
       
   226     /**
       
   227      * Creates a file dialog window with the specified title for loading
       
   228      * or saving a file.
       
   229      * <p>
       
   230      * If the value of <code>mode</code> is <code>LOAD</code>, then the
       
   231      * file dialog is finding a file to read, and the files shown are those
       
   232      * in the current directory.   If the value of
       
   233      * <code>mode</code> is <code>SAVE</code>, the file dialog is finding
       
   234      * a place to write a file.
       
   235      *
       
   236      * @param     parent   the owner of the dialog
       
   237      * @param     title    the title of the dialog; a <code>null</code> value
       
   238      *                     will be accepted without causing a
       
   239      *                     <code>NullPointerException</code> to be thrown
       
   240      * @param     mode     the mode of the dialog; either
       
   241      *                     <code>FileDialog.LOAD</code> or <code>FileDialog.SAVE</code>
       
   242      * @exception java.lang.IllegalArgumentException if an illegal
       
   243      *            file dialog mode is supplied;
       
   244      * @exception java.lang.IllegalArgumentException if the <code>parent</code>'s
       
   245      *            <code>GraphicsConfiguration</code>
       
   246      *            is not from a screen device;
       
   247      * @exception java.lang.IllegalArgumentException if <code>parent</code>
       
   248      *            is <code>null</code>; this exception is always thrown when
       
   249      *            <code>GraphicsEnvironment.isHeadless</code>
       
   250      *            returns <code>true</code>
       
   251      * @see       java.awt.GraphicsEnvironment#isHeadless
       
   252      * @see       java.awt.FileDialog#LOAD
       
   253      * @see       java.awt.FileDialog#SAVE
       
   254      * @since     1.5
       
   255      */
       
   256     public FileDialog(Dialog parent, String title, int mode) {
       
   257         super(parent, title, true);
       
   258         this.setMode(mode);
       
   259         setLayout(null);
       
   260     }
       
   261 
       
   262     /**
       
   263      * Constructs a name for this component. Called by <code>getName()</code>
       
   264      * when the name is <code>null</code>.
       
   265      */
       
   266     String constructComponentName() {
       
   267         synchronized (FileDialog.class) {
       
   268             return base + nameCounter++;
       
   269         }
       
   270     }
       
   271 
       
   272     /**
       
   273      * Creates the file dialog's peer.  The peer allows us to change the look
       
   274      * of the file dialog without changing its functionality.
       
   275      */
       
   276     public void addNotify() {
       
   277         synchronized(getTreeLock()) {
       
   278             if (parent != null && parent.getPeer() == null) {
       
   279                 parent.addNotify();
       
   280             }
       
   281             if (peer == null)
       
   282                 peer = getToolkit().createFileDialog(this);
       
   283             super.addNotify();
       
   284         }
       
   285     }
       
   286 
       
   287     /**
       
   288      * Indicates whether this file dialog box is for loading from a file
       
   289      * or for saving to a file.
       
   290      *
       
   291      * @return   the mode of this file dialog window, either
       
   292      *               <code>FileDialog.LOAD</code> or
       
   293      *               <code>FileDialog.SAVE</code>
       
   294      * @see      java.awt.FileDialog#LOAD
       
   295      * @see      java.awt.FileDialog#SAVE
       
   296      * @see      java.awt.FileDialog#setMode
       
   297      */
       
   298     public int getMode() {
       
   299         return mode;
       
   300     }
       
   301 
       
   302     /**
       
   303      * Sets the mode of the file dialog.  If <code>mode</code> is not
       
   304      * a legal value, an exception will be thrown and <code>mode</code>
       
   305      * will not be set.
       
   306      *
       
   307      * @param      mode  the mode for this file dialog, either
       
   308      *                 <code>FileDialog.LOAD</code> or
       
   309      *                 <code>FileDialog.SAVE</code>
       
   310      * @see        java.awt.FileDialog#LOAD
       
   311      * @see        java.awt.FileDialog#SAVE
       
   312      * @see        java.awt.FileDialog#getMode
       
   313      * @exception  IllegalArgumentException if an illegal file
       
   314      *                 dialog mode is supplied
       
   315      * @since      JDK1.1
       
   316      */
       
   317     public void setMode(int mode) {
       
   318         switch (mode) {
       
   319           case LOAD:
       
   320           case SAVE:
       
   321             this.mode = mode;
       
   322             break;
       
   323           default:
       
   324             throw new IllegalArgumentException("illegal file dialog mode");
       
   325         }
       
   326     }
       
   327 
       
   328     /**
       
   329      * Gets the directory of this file dialog.
       
   330      *
       
   331      * @return  the (potentially <code>null</code> or invalid)
       
   332      *          directory of this <code>FileDialog</code>
       
   333      * @see       java.awt.FileDialog#setDirectory
       
   334      */
       
   335     public String getDirectory() {
       
   336         return dir;
       
   337     }
       
   338 
       
   339     /**
       
   340      * Sets the directory of this file dialog window to be the
       
   341      * specified directory. Specifying a <code>null</code> or an
       
   342      * invalid directory implies an implementation-defined default.
       
   343      * This default will not be realized, however, until the user
       
   344      * has selected a file. Until this point, <code>getDirectory()</code>
       
   345      * will return the value passed into this method.
       
   346      * <p>
       
   347      * Specifying "" as the directory is exactly equivalent to
       
   348      * specifying <code>null</code> as the directory.
       
   349      *
       
   350      * @param     dir   the specified directory
       
   351      * @see       java.awt.FileDialog#getDirectory
       
   352      */
       
   353     public void setDirectory(String dir) {
       
   354         this.dir = (dir != null && dir.equals("")) ? null : dir;
       
   355         FileDialogPeer peer = (FileDialogPeer)this.peer;
       
   356         if (peer != null) {
       
   357             peer.setDirectory(this.dir);
       
   358         }
       
   359     }
       
   360 
       
   361     /**
       
   362      * Gets the selected file of this file dialog.  If the user
       
   363      * selected <code>CANCEL</code>, the returned file is <code>null</code>.
       
   364      *
       
   365      * @return    the currently selected file of this file dialog window,
       
   366      *                or <code>null</code> if none is selected
       
   367      * @see       java.awt.FileDialog#setFile
       
   368      */
       
   369     public String getFile() {
       
   370         return file;
       
   371     }
       
   372 
       
   373     /**
       
   374      * Sets the selected file for this file dialog window to be the
       
   375      * specified file. This file becomes the default file if it is set
       
   376      * before the file dialog window is first shown.
       
   377      * <p>
       
   378      * Specifying "" as the file is exactly equivalent to specifying
       
   379      * <code>null</code>
       
   380      * as the file.
       
   381      *
       
   382      * @param    file   the file being set
       
   383      * @see      java.awt.FileDialog#getFile
       
   384      */
       
   385     public void setFile(String file) {
       
   386         this.file = (file != null && file.equals("")) ? null : file;
       
   387         FileDialogPeer peer = (FileDialogPeer)this.peer;
       
   388         if (peer != null) {
       
   389             peer.setFile(this.file);
       
   390         }
       
   391     }
       
   392 
       
   393     /**
       
   394      * Determines this file dialog's filename filter. A filename filter
       
   395      * allows the user to specify which files appear in the file dialog
       
   396      * window.  Filename filters do not function in Sun's reference
       
   397      * implementation for Microsoft Windows.
       
   398      *
       
   399      * @return    this file dialog's filename filter
       
   400      * @see       java.io.FilenameFilter
       
   401      * @see       java.awt.FileDialog#setFilenameFilter
       
   402      */
       
   403     public FilenameFilter getFilenameFilter() {
       
   404         return filter;
       
   405     }
       
   406 
       
   407     /**
       
   408      * Sets the filename filter for this file dialog window to the
       
   409      * specified filter.
       
   410      * Filename filters do not function in Sun's reference
       
   411      * implementation for Microsoft Windows.
       
   412      *
       
   413      * @param   filter   the specified filter
       
   414      * @see     java.io.FilenameFilter
       
   415      * @see     java.awt.FileDialog#getFilenameFilter
       
   416      */
       
   417     public synchronized void setFilenameFilter(FilenameFilter filter) {
       
   418         this.filter = filter;
       
   419         FileDialogPeer peer = (FileDialogPeer)this.peer;
       
   420         if (peer != null) {
       
   421             peer.setFilenameFilter(filter);
       
   422         }
       
   423     }
       
   424 
       
   425     /**
       
   426      * Reads the <code>ObjectInputStream</code> and performs
       
   427      * a backwards compatibility check by converting
       
   428      * either a <code>dir</code> or a <code>file</code>
       
   429      * equal to an empty string to <code>null</code>.
       
   430      *
       
   431      * @param s the <code>ObjectInputStream</code> to read
       
   432      */
       
   433     private void readObject(ObjectInputStream s)
       
   434         throws ClassNotFoundException, IOException
       
   435     {
       
   436         s.defaultReadObject();
       
   437 
       
   438         // 1.1 Compatibility: "" is not converted to null in 1.1
       
   439         if (dir != null && dir.equals("")) {
       
   440             dir = null;
       
   441         }
       
   442         if (file != null && file.equals("")) {
       
   443             file = null;
       
   444         }
       
   445     }
       
   446 
       
   447     /**
       
   448      * Returns a string representing the state of this <code>FileDialog</code>
       
   449      * window. This method is intended to be used only for debugging purposes,
       
   450      * and the content and format of the returned string may vary between
       
   451      * implementations. The returned string may be empty but may not be
       
   452      * <code>null</code>.
       
   453      *
       
   454      * @return  the parameter string of this file dialog window
       
   455      */
       
   456     protected String paramString() {
       
   457         String str = super.paramString();
       
   458         str += ",dir= " + dir;
       
   459         str += ",file= " + file;
       
   460         return str + ((mode == LOAD) ? ",load" : ",save");
       
   461     }
       
   462 
       
   463     boolean postsOldMouseEvents() {
       
   464         return false;
       
   465     }
       
   466 }