001/* FileSystemView.java --
002   Copyright (C) 2002, 2004, 2005  Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038package javax.swing.filechooser;
039
040import java.io.File;
041import java.io.IOException;
042import java.util.ArrayList;
043
044import javax.swing.Icon;
045import javax.swing.JFileChooser;
046
047
048/**
049 * The base class providing a view of the file system for use by the
050 * {@link JFileChooser} component.
051 */
052public abstract class FileSystemView
053{
054  /** The instance returned by {@link #getFileSystemView()}. */
055  private static FileSystemView defaultFileSystemView;
056
057  /**
058   * Creates a new file object with the given name in the specified directory.
059   *
060   * @param dir  the directory (<code>null</code> permitted).
061   * @param filename  the file name.
062   *
063   * @return A new file object.
064   */
065  public File createFileObject(File dir, String filename)
066  {
067    return new File(dir, filename);
068  }
069
070  /**
071   * Creates a new file object from the specified path.
072   *
073   * @param path  the path.
074   *
075   * @return A new file object.
076   */
077  public File createFileObject(String path)
078  {
079    File f = new File(path);
080    if (isFileSystemRoot(f))
081      f = this.createFileSystemRoot(f);
082    return f;
083  }
084
085  /**
086   * DOCUMENT ME!
087   *
088   * @param f DOCUMENT ME!
089   *
090   * @return DOCUMENT ME!
091   */
092  protected File createFileSystemRoot(File f)
093  {
094    File[] roots = File.listRoots();
095    if (roots == null)
096      return null;
097    return roots[0];
098  }
099
100  /**
101   * Creates a new folder with a unique name in the specified directory and
102   * returns a {@link File} object representing the new directory.
103   *
104   * @param containingDir  the directory to contain the new folder
105   *                       (<code>null</code> not permitted).
106   *
107   * @return A {@link File} object representing the new directory.
108   *
109   * @throws IOException if an exception occurs while creating the new
110   *                     directory.
111   */
112  public abstract File createNewFolder(File containingDir)
113                                throws IOException;
114
115  /**
116   * DOCUMENT ME!
117   *
118   * @param parent DOCUMENT ME!
119   * @param fileName DOCUMENT ME!
120   *
121   * @return DOCUMENT ME!
122   */
123  public File getChild(File parent, String fileName)
124  {
125    // FIXME: Handle the case when parent and child are special folders.
126    return new File(parent, fileName);
127  }
128
129  /**
130   * Returns the default directory.
131   *
132   * @return The default directory.
133   */
134  public File getDefaultDirectory()
135  {
136    return getHomeDirectory();
137  }
138
139  /**
140   * Returns an array containing the files in the given directory.  The
141   * <code>useFileHiding</code> controls whether or not hidden files are
142   * included in the result.
143   *
144   * @param dir  the directory (if <code>null</code>
145   * @param useFileHiding  a flag that controls whether or not hidden files are
146   *                       included in the result (pass in <code>true</code> to
147   *                       exclude hidden files).
148   *
149   * @return The files in the given directory (possibly <code>null</code>).
150   */
151  public File[] getFiles(File dir, boolean useFileHiding)
152  {
153    if (dir == null || dir.listFiles() == null)
154      return null;
155    File[] files = dir.listFiles();
156    if (! useFileHiding)
157      return files;
158    ArrayList trim = new ArrayList();
159    for (int i = 0; i < files.length; i++)
160      if (! files[i].isHidden())
161        trim.add(files[i]);
162    File[] value = (File[]) trim.toArray(new File[trim.size()]);
163    return value;
164  }
165
166  /**
167   * Returns a default {@link FileSystemView} appropriate for the platform.
168   *
169   * @return A default {@link FileSystemView} appropriate for the platform.
170   */
171  public static FileSystemView getFileSystemView()
172  {
173    if (defaultFileSystemView == null)
174      {
175        // FIXME: We need to support other file systems too.
176        defaultFileSystemView = new UnixFileSystemView();
177      }
178    return defaultFileSystemView;
179  }
180
181  /**
182   * Returns the home directory for the current user.
183   *
184   * @return The home directory for the current user.
185   */
186  public File getHomeDirectory()
187  {
188    return createFileObject(System.getProperty("user.home"));
189  }
190
191  /**
192   * Returns the parent directory for the given file/directory.
193   *
194   * @param f  the file/directory.
195   *
196   * @return The parent directory (or <code>null</code> if there is no parent
197   *         directory).
198   */
199  public File getParentDirectory(File f)
200  {
201    if (f == null)
202      return null;
203    return f.getParentFile();
204  }
205
206  /**
207   * Returns an array containing the file system roots.  On Unix-like platforms,
208   * this array will contain just a single item ("/"), while other platforms
209   * may return multiple roots.
210   * <p>
211   * This method is implemented to return <code>null</code>, subclasses must
212   * override this method.
213   *
214   * @return An array containing the file system roots.
215   */
216  public File[] getRoots()
217  {
218    // subclass
219    return null;
220  }
221
222  /**
223   * Returns the name of a file as it would be displayed by the underlying
224   * system.
225   *
226   * @param f  the file.
227   *
228   * @return the name of a file as it would be displayed by the underlying
229   *         system
230   *
231   * @specnote The specification suggests that the information here is
232   *           fetched from a ShellFolder class. This seems to be a non public
233   *           private file handling class. We simply return File.getName()
234   *           here and leave special handling to subclasses.
235   */
236  public String getSystemDisplayName(File f)
237  {
238    String name = null;
239    if (f != null)
240      name = f.getName();
241    return name;
242  }
243
244  /**
245   * Returns the icon that would be displayed for the given file by the
246   * underlying system.  This implementation returns <code>null</code>,
247   * subclasses must override.
248   *
249   * @param f  the file.
250   *
251   * @return <code>null</code>.
252   */
253  public Icon getSystemIcon(File f)
254  {
255    return null;
256  }
257
258  /**
259   * Returns the type description of a file that would be displayed by the
260   * underlying system.  This implementation returns <code>null</code>,
261   * subclasses must override.
262   *
263   * @param f  the file.
264   *
265   * @return <code>null</code>.
266   */
267  public String getSystemTypeDescription(File f)
268  {
269    return null;
270  }
271
272  /**
273   * DOCUMENT ME!
274   *
275   * @param dir DOCUMENT ME!
276   *
277   * @return DOCUMENT ME!
278   */
279  public boolean isComputerNode(File dir)
280  {
281    return false;
282  }
283
284  /**
285   * Returns <code>true</code> if the given directory represents a disk
286   * drive, and <code>false</code> otherwise.  This default implementation
287   * always returns <code>false</code>.
288   *
289   * @param dir  the directory.
290   *
291   * @return <code>false</code>.
292   */
293  public boolean isDrive(File dir)
294  {
295    return false;
296  }
297
298  /**
299   * Returns <code>true</code> if <code>f</code> is a file or directory, and
300   * <code>false</code> otherwise.
301   *
302   * @param f  the file/directory.
303   *
304   * @return <code>true</code> if <code>f</code> is a file or directory, and
305   * <code>false</code> otherwise.
306   */
307  public boolean isFileSystem(File f)
308  {
309    return (f.isFile() || f.isDirectory());
310  }
311
312  /**
313   * Returns <code>true</code> if the given directory is a file system root,
314   * and <code>false</code> otherwise.
315   *
316   * @param dir  the directory.
317   *
318   * @return <code>true</code> if the given directory is a file system root,
319   *          and <code>false</code> otherwise.
320   */
321  public boolean isFileSystemRoot(File dir)
322  {
323    File[] roots = File.listRoots();
324    if (roots == null || dir == null)
325      return false;
326    String filename = dir.getAbsolutePath();
327    for (int i = 0; i < roots.length; i++)
328      if (roots[i].getAbsolutePath().equals(filename))
329        return true;
330    return false;
331  }
332
333  /**
334   * Returns <code>true</code> if the given directory represents a floppy
335   * drive, and <code>false</code> otherwise.  This default implementation
336   * always returns <code>false</code>.
337   *
338   * @param dir  the directory.
339   *
340   * @return <code>false</code>.
341   */
342  public boolean isFloppyDrive(File dir)
343  {
344    return false;
345  }
346
347  /**
348   * Returns <code>true</code> if the given file is hidden, and
349   * <code>false</code> otherwise.
350   *
351   * @param f  the file.
352   *
353   * @return <code>true</code> if the given file is hidden, and
354   *         <code>false</code> otherwise.
355   */
356  public boolean isHiddenFile(File f)
357  {
358    return f.isHidden();
359  }
360
361  /**
362   * Returns <code>true</code> if <code>folder</code> is the parent of
363   * <code>file</code>, and <code>false</code> otherwise.
364   *
365   * @param folder  the folder (<code>null</code> not permitted).
366   * @param file  the file (<code>null</code> not permitted).
367   *
368   * @return <code>true</code> if <code>folder</code> is the parent of
369   *         <code>file</code>, and <code>false</code> otherwise.
370   */
371  public boolean isParent(File folder, File file)
372  {
373    File parent = file.getParentFile();
374    if (parent == null)
375      return false;
376    return folder.equals(parent);
377  }
378
379  /**
380   * DOCUMENT ME!
381   *
382   * @param f DOCUMENT ME!
383   *
384   * @return DOCUMENT ME!
385   */
386  public boolean isRoot(File f)
387  {
388    // These are not file system roots.
389    return false;
390  }
391
392  /**
393   * Returns <code>true</code> if the file is traversable, and
394   * <code>false</code> otherwise.  Here, all directories are considered
395   * traversable, and files are considered non-traversable.
396   *
397   * @param f  the file or directory (<code>null</code> not permitted).
398   *
399   * @return <code>true</code> if the file is traversable, and
400   *         <code>false</code> otherwise.
401   */
402  public Boolean isTraversable(File f)
403  {
404    // Tested. A directory where the user has no permission to rwx is still
405    // traversable. (No files are listed when you traverse the directory)
406    // My best guess is that as long as it's a directory, the file is
407    // traversable.
408    return Boolean.valueOf(f.isDirectory());
409  }
410}