Java tutorial
/* * Copyright (c) 1998, 2014, 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 javax.swing.filechooser; import java.io.File; import javax.swing.*; /** * <code>FileView</code> defines an abstract class that can be implemented * to provide the filechooser with UI information for a <code>File</code>. * Each L&F <code>JFileChooserUI</code> object implements this * class to pass back the correct icons and type descriptions specific to * that L&F. For example, the Microsoft Windows L&F returns the * generic Windows icons for directories and generic files. * Additionally, you may want to provide your own <code>FileView</code> to * <code>JFileChooser</code> to return different icons or additional * information using {@link javax.swing.JFileChooser#setFileView}. * * <p> * * <code>JFileChooser</code> first looks to see if there is a user defined * <code>FileView</code>, if there is, it gets type information from * there first. If <code>FileView</code> returns <code>null</code> for * any method, <code>JFileChooser</code> then uses the L&F specific * view to get the information. * So, for example, if you provide a <code>FileView</code> class that * returns an <code>Icon</code> for JPG files, and returns <code>null</code> * icons for all other files, the UI's <code>FileView</code> will provide * default icons for all other files. * * <p> * * For an example implementation of a simple file view, see * <code><i>yourJDK</i>/demo/jfc/FileChooserDemo/ExampleFileView.java</code>. * For more information and examples see * <a href="https://docs.oracle.com/javase/tutorial/uiswing/components/filechooser.html">How to Use File Choosers</a>, * a section in <em>The Java Tutorial</em>. * * @see javax.swing.JFileChooser * * @author Jeff Dinkins * */ public abstract class FileView { /** * The name of the file. Normally this would be simply * <code>f.getName()</code>. * * @param f a {@code File} object * @return a {@code String} representing the name of the file */ public String getName(File f) { return null; }; /** * A human readable description of the file. For example, * a file named <i>jag.jpg</i> might have a description that read: * "A JPEG image file of James Gosling's face". * * @param f a {@code File} object * @return a {@code String} containing a description of the file or * {@code null} if it is not available. * */ public String getDescription(File f) { return null; } /** * A human readable description of the type of the file. For * example, a <code>jpg</code> file might have a type description of: * "A JPEG Compressed Image File" * * @param f a {@code File} object * @return a {@code String} containing a description of the type of the file * or {@code null} if it is not available . */ public String getTypeDescription(File f) { return null; } /** * The icon that represents this file in the <code>JFileChooser</code>. * * @param f a {@code File} object * @return an {@code Icon} which represents the specified {@code File} or * {@code null} if it is not available. */ public Icon getIcon(File f) { return null; } /** * Whether the directory is traversable or not. This might be * useful, for example, if you want a directory to represent * a compound document and don't want the user to descend into it. * * @param f a {@code File} object representing a directory * @return {@code true} if the directory is traversable, * {@code false} if it is not, and {@code null} if the * file system should be checked. * @see FileSystemView#isTraversable */ public Boolean isTraversable(File f) { return null; } }