1 /*
   2  * Copyright (c) 1998, 2014, Oracle and/or its affiliates. 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.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package javax.swing.filechooser;
  27 
  28 import java.io.File;
  29 import javax.swing.*;
  30 
  31 /**
  32  * <code>FileView</code> defines an abstract class that can be implemented
  33  * to provide the filechooser with UI information for a <code>File</code>.
  34  * Each L&amp;F <code>JFileChooserUI</code> object implements this
  35  * class to pass back the correct icons and type descriptions specific to
  36  * that L&amp;F. For example, the Microsoft Windows L&amp;F returns the
  37  * generic Windows icons for directories and generic files.
  38  * Additionally, you may want to provide your own <code>FileView</code> to
  39  * <code>JFileChooser</code> to return different icons or additional
  40  * information using {@link javax.swing.JFileChooser#setFileView}.
  41  *
  42  * <p>
  43  *
  44  * <code>JFileChooser</code> first looks to see if there is a user defined
  45  * <code>FileView</code>, if there is, it gets type information from
  46  * there first. If <code>FileView</code> returns <code>null</code> for
  47  * any method, <code>JFileChooser</code> then uses the L&amp;F specific
  48  * view to get the information.
  49  * So, for example, if you provide a <code>FileView</code> class that
  50  * returns an <code>Icon</code> for JPG files, and returns <code>null</code>
  51  * icons for all other files, the UI's <code>FileView</code> will provide
  52  * default icons for all other files.
  53  *
  54  * <p>
  55  *
  56  * For an example implementation of a simple file view, see
  57  * <code><i>yourJDK</i>/demo/jfc/FileChooserDemo/ExampleFileView.java</code>.
  58  * For more information and examples see
  59  * <a
  60  href="http://docs.oracle.com/javase/tutorial/uiswing/components/filechooser.html">How to Use File Choosers</a>,
  61  * a section in <em>The Java Tutorial</em>.
  62  *
  63  * @see javax.swing.JFileChooser
  64  *
  65  * @author Jeff Dinkins
  66  *
  67  */
  68 public abstract class FileView {
  69     /**
  70      * The name of the file. Normally this would be simply
  71      * <code>f.getName()</code>.
  72      *
  73      * @param f a {@code File} object
  74      * @return a {@code String} representing the name of the file
  75      */
  76     public String getName(File f) {
  77         return null;
  78     };
  79 
  80     /**
  81      * A human readable description of the file. For example,
  82      * a file named <i>jag.jpg</i> might have a description that read:
  83      * "A JPEG image file of James Gosling's face".
  84      *
  85      * @param f a {@code File} object
  86      * @return a {@code String} containing a description of the file or
  87      *         {@code null} if it is not available.
  88      *
  89      */
  90     public String getDescription(File f) {
  91         return null;
  92     }
  93 
  94     /**
  95      * A human readable description of the type of the file. For
  96      * example, a <code>jpg</code> file might have a type description of:
  97      * "A JPEG Compressed Image File"
  98      *
  99      * @param f a {@code File} object
 100      * @return a {@code String} containing a description of the type of the file
 101      *         or {@code null} if it is not available   .
 102      */
 103     public String getTypeDescription(File f) {
 104         return null;
 105     }
 106 
 107     /**
 108      * The icon that represents this file in the <code>JFileChooser</code>.
 109      *
 110      * @param f a {@code File} object
 111      * @return an {@code Icon} which represents the specified {@code File} or
 112      *         {@code null} if it is not available.
 113      */
 114     public Icon getIcon(File f) {
 115         return null;
 116     }
 117 
 118     /**
 119      * Whether the directory is traversable or not. This might be
 120      * useful, for example, if you want a directory to represent
 121      * a compound document and don't want the user to descend into it.
 122      *
 123      * @param f a {@code File} object representing a directory
 124      * @return {@code true} if the directory is traversable,
 125      *         {@code false} if it is not, and {@code null} if the
 126      *         file system should be checked.
 127      * @see FileSystemView#isTraversable
 128      */
 129     public Boolean isTraversable(File f) {
 130         return null;
 131     }
 132 
 133 }
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