PseudoNetworkFile


1   /*
2    * Copyright (C) 2005 Alfresco, Inc.
3    *
4    * Licensed under the Mozilla Public License version 1.1 
5    * with a permitted attribution clause. You may obtain a
6    * copy of the License at
7    *
8    *   http://www.alfresco.org/legal/license.txt
9    *
10   * Unless required by applicable law or agreed to in writing,
11   * software distributed under the License is distributed on an
12   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
13   * either express or implied. See the License for the specific
14   * language governing permissions and limitations under the
15   * License.
16   */
17  
18  package org.alfresco.filesys.smb.server.repo.pseudo;
19  
20  import java.io.File  ;
21  import java.io.IOException  ;
22  import java.io.RandomAccessFile  ;
23  
24  import org.alfresco.filesys.server.filesys.AccessDeniedException;
25  import org.alfresco.filesys.server.filesys.NetworkFile;
26  import org.alfresco.filesys.smb.SeekType;
27  
28  /**
29   * Pseudo File Network File Class
30   * <p>
31   * Represents an open pseudo file and provides access to the file data.
32   * 
33   * @author gkspencer
34   */
35  public class PseudoNetworkFile extends NetworkFile
36  {
37      // File details
38  
39      protected File   m_file;
40  
41      // Random access file used to read/write the actual file
42  
43      protected RandomAccessFile   m_io;
44  
45      // End of file flag
46  
47      protected boolean m_eof;
48  
49      /**
50       * Class constructor.
51       * 
52       * @param name String
53       * @param localPath String
54       * @param netPath String
55       */
56      public PseudoNetworkFile(String   name, String   localPath, String   netPath)
57      {
58          super( name);
59  
60          // Set the file using the existing file object
61  
62          m_file = new File  ( localPath);
63  
64          // Set the file size
65  
66          setFileSize(m_file.length());
67          m_eof = false;
68  
69          // Set the modification date/time, if available. Fake the creation date/time as it's not
70          // available from the File class
71  
72          long modDate = m_file.lastModified();
73          setModifyDate(modDate);
74          setCreationDate(modDate);
75  
76          // Set the file id
77  
78          setFileId(netPath.hashCode());
79          
80          // Set the full relative path
81          
82          setFullName( netPath);
83      }
84  
85      /**
86       * Close the network file.
87       */
88      public void closeFile() throws java.io.IOException  
89      {
90  
91          // Close the file, if used
92  
93          if (m_io != null)
94          {
95  
96              // Close the file
97  
98              m_io.close();
99              m_io = null;
100 
101             // Set the last modified date/time for the file
102 
103             if (this.getWriteCount() > 0)
104                 m_file.setLastModified(System.currentTimeMillis());
105 
106             // Indicate that the file is closed
107 
108             setClosed(true);
109         }
110     }
111 
112     /**
113      * Return the current file position.
114      * 
115      * @return long
116      */
117     public long currentPosition()
118     {
119 
120         // Check if the file is open
121 
122         try
123         {
124             if (m_io != null)
125                 return m_io.getFilePointer();
126         }
127         catch (Exception   ex)
128         {
129         }
130         return 0;
131     }
132 
133     /**
134      * Flush the file.
135      * 
136      * @exception IOException
137      */
138     public void flushFile() throws IOException  
139     {
140         // Flush all buffered data
141 
142         if (m_io != null)
143             m_io.getFD().sync();
144     }
145 
146     /**
147      * Determine if the end of file has been reached.
148      * 
149      * @return boolean
150      */
151     public boolean isEndOfFile() throws java.io.IOException  
152     {
153         // Check if we reached end of file
154 
155         if (m_io != null && m_io.getFilePointer() == m_io.length())
156             return true;
157         return false;
158     }
159 
160     /**
161      * Open the file.
162      * 
163      * @param createFlag boolean
164      * @exception IOException
165      */
166     public void openFile(boolean createFlag) throws java.io.IOException  
167     {
168 
169         synchronized (m_file)
170         {
171             // Check if the file is open
172 
173             if (m_io == null)
174             {
175 
176                 // Open the file, always read-only for now
177 
178                 m_io = new RandomAccessFile  (m_file, "r");
179 
180                 // Indicate that the file is open
181 
182                 setClosed(false);
183             }
184         }
185     }
186 
187     /**
188      * Read from the file.
189      * 
190      * @param buf byte[]
191      * @param len int
192      * @param pos int
193      * @param fileOff long
194      * @return Length of data read.
195      * @exception IOException
196      */
197     public int readFile(byte[] buf, int len, int pos, long fileOff) throws java.io.IOException  
198     {
199 
200         // Open the file, if not already open
201 
202         if (m_io == null)
203             openFile(false);
204 
205         // Seek to the required file position
206 
207         if (currentPosition() != fileOff)
208             seekFile(fileOff, SeekType.StartOfFile);
209 
210         // Read from the file
211 
212         int rdlen = m_io.read(buf, pos, len);
213 
214         // Return the actual length of data read
215 
216         return rdlen;
217     }
218 
219     /**
220      * Seek to the specified file position.
221      * 
222      * @param pos long
223      * @param typ int
224      * @return long
225      * @exception IOException
226      */
227     public long seekFile(long pos, int typ) throws IOException  
228     {
229 
230         // Open the file, if not already open
231 
232         if (m_io == null)
233             openFile(false);
234 
235         // Check if the current file position is the required file position
236 
237         switch (typ)
238         {
239 
240         // From start of file
241 
242         case SeekType.StartOfFile:
243             if (currentPosition() != pos)
244                 m_io.seek(pos);
245             break;
246 
247         // From current position
248 
249         case SeekType.CurrentPos:
250             m_io.seek(currentPosition() + pos);
251             break;
252 
253         // From end of file
254 
255         case SeekType.EndOfFile: {
256             long newPos = m_io.length() + pos;
257             m_io.seek(newPos);
258         }
259             break;
260         }
261 
262         // Return the new file position
263 
264         return currentPosition();
265     }
266 
267     /**
268      * Truncate the file
269      * 
270      * @param siz long
271      * @exception IOException
272      */
273     public void truncateFile(long siz) throws IOException  
274     {
275         // Do not allow the file to be written to
276         
277         throw new AccessDeniedException("Cannot truncate pseudo file");
278     }
279 
280     /**
281      * Write a block of data to the file.
282      * 
283      * @param buf byte[]
284      * @param len int
285      * @exception IOException
286      */
287     public void writeFile(byte[] buf, int len, int pos) throws java.io.IOException  
288     {
289         // Do not allow the file to be written to
290         
291         throw new AccessDeniedException("Cannot write to pseudo file");
292     }
293 
294     /**
295      * Write a block of data to the file.
296      * 
297      * @param buf byte[]
298      * @param len int
299      * @param pos int
300      * @param offset long
301      * @exception IOException
302      */
303     public void writeFile(byte[] buf, int len, int pos, long offset) throws java.io.IOException  
304     {
305         // Do not allow the file to be written to
306         
307         throw new AccessDeniedException("Cannot write to pseudo file");
308     }
309 }
310
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