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      1 /*
      2  * Copyright (C) 2003-2009 JNode.org
      3  *               2009,2010 Matthias Treydte <mt (at) waldheinz.de>
      4  *
      5  * This library is free software; you can redistribute it and/or modify it
      6  * under the terms of the GNU Lesser General Public License as published
      7  * by the Free Software Foundation; either version 2.1 of the License, or
      8  * (at your option) any later version.
      9  *
     10  * This library is distributed in the hope that it will be useful, but
     11  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
     12  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
     13  * License for more details.
     14  *
     15  * You should have received a copy of the GNU Lesser General Public License
     16  * along with this library; If not, write to the Free Software Foundation, Inc.,
     17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
     18  */
     19 
     20 package de.waldheinz.fs;
     21 
     22 import java.io.IOException;
     23 
     24 /**
     25  * The interface common to all file system implementations.
     26  *
     27  * @author Ewout Prangsma &lt;epr at jnode.org&gt;
     28  * @author Matthias Treydte &lt;waldheinz at gmail.com&gt;
     29  */
     30 public interface FileSystem {
     31 
     32     /**
     33      * Gets the root entry of this filesystem. This is usually a directory, but
     34      * this is not required.
     35      *
     36      * @return the file system's root entry
     37      * @throws IOException on read error
     38      */
     39     public FsDirectory getRoot() throws IOException;
     40 
     41     /**
     42      * Returns if this {@code FileSystem} is in read-only mode.
     43      *
     44      * @return if this {@code FileSystem} is read-only
     45      */
     46     public boolean isReadOnly();
     47 
     48     /**
     49      * Close this file system. After a close, all invocations of methods of
     50      * this file system or objects created by this file system will throw an
     51      * {@link IllegalStateException}.
     52      *
     53      * @throws IOException on error closing the file system
     54      */
     55     public void close() throws IOException;
     56 
     57     /**
     58      * Returns {@code true} if this file system is closed. If the file system
     59      * is closed, no more operations may be performed on it.
     60      *
     61      * @return if this file system is closed
     62      */
     63     public boolean isClosed();
     64 
     65     /**
     66      * The total size of this file system.
     67      *
     68      * @return if -1 this feature is unsupported
     69      * @throws IOException if an I/O error occurs
     70      */
     71     public long getTotalSpace() throws IOException;
     72 
     73     /**
     74      * The free space of this file system.
     75      *
     76      * @return if -1 this feature is unsupported
     77      * @throws IOException if an I/O error occurs
     78      */
     79     public long getFreeSpace() throws IOException;
     80 
     81     /**
     82      * The usable space of this file system.
     83      *
     84      * @return if -1 this feature is unsupported
     85      * @throws IOException if an I/O error occurs
     86      */
     87     public long getUsableSpace() throws IOException;
     88 
     89     /**
     90      * Flushes any modified file system structures to the underlying storage.
     91      *
     92      * @throws IOException
     93      */
     94     public void flush() throws IOException;
     95 }
     96