VFile


1   /*
2    * Copyright (C) The Apache Software Foundation. All rights reserved.
3    *
4    * This software is published under the terms of the Apache Software License
5    * version 1.1, a copy of which has been included with this distribution in
6    * the LICENSE.txt file.
7    */
8   package org.apache.avalon.excalibur.vfs;
9   
10  import java.io.InputStream  ;
11  import java.io.IOException  ;
12  
13  /**
14   * File on virtual file system.
15   *
16   * @author <a HREF="mailto:peter@apache.org">Peter Donald</a>
17   */
18  public final class VFile
19  {
20      ///Complete Path to file
21      private final String             m_path;
22  
23      ///Underlying resource that if VFileAccessor specific
24      private Object                   m_resource;
25  
26      ///VFileAccessor via which file is accessed
27      private VFileAccessor          m_accessor;
28  
29      ///Virtual file system in which this VFile is mounted
30      private VFileSystem            m_filesystem;
31  
32      /**
33       * Constructor for creating a directory entry.
34       *
35       * @param path the path to directory
36       * @param filesystem the filesystem VFile belongs to
37       */
38      protected VFile( final String   path, final VFileSystem filesystem )
39      {
40          this( path, filesystem, null, null );
41      }
42  
43      /**
44       * Constructor for creating a vfile.
45       *
46       * @param path the path to directory
47       * @param filesystem the filesystem VFile belongs to
48       * @param resource resource represented by vfile. Must be non-null if accessor non-null.
49       * @param accessor accessor to access vfile. Must be non-null if resource non-null.
50       * @exception IllegalArgumentException if an error occurs
51       */
52      protected VFile( final String   path, 
53                       final VFileSystem filesystem,                     
54                       final Object   resource,
55                       final VFileAccessor accessor )
56          throws IllegalArgumentException  
57      {
58          m_path = path;
59          m_filesystem = filesystem;
60          m_resource = resource;
61          m_accessor = accessor;
62  
63          if( null == resource || null == accessor )
64          {
65              if( null != resource && null != accessor )
66              {
67                  throw new IllegalArgumentException  ( "Resource and accessor must " +
68                                                      "be both null or non-null" );
69              }
70          }
71      }
72  
73      /**
74       * Get path to file.
75       *
76       * @return the path to file
77       */
78      public String   getPath()
79      {
80          return m_path;
81      }
82  
83      /**
84       * Get name of file.
85       *
86       * @return the name of file
87       */
88      public String   getName()
89      { 
90          final int index = m_path.lastIndexOf( '/' );
91          if( -1 == index )
92          {
93              return m_path;
94          }
95          else
96          {
97              return m_path.substring( index );
98          }
99      }
100 
101     public VFile getParent()
102         throws IOException  
103     { 
104         checkValid();
105         return m_filesystem.get( getParentsName() ); 
106     }
107 
108     public VFile[] list()
109         throws IOException  
110     { 
111         checkValid();
112         return m_filesystem.list( this ); 
113     }
114 
115     public VFile[] list( final VFileFilter filter )
116         throws IOException  
117     { 
118         checkValid();
119         return m_filesystem.list( this, filter ); 
120     }
121 
122     public boolean isDirectory()
123     {
124         return ( null == m_resource );
125     }
126 
127     public boolean isFile()
128     {
129         return ( null != m_resource );
130     }
131 
132     public long getSize()
133         throws IOException  
134     {
135         checkValid();
136         if( isDirectory() ) return 0;
137         else
138         {
139             return m_accessor.getSize( this, m_resource );
140         }
141     }
142 
143     public InputStream   getInputStream()
144         throws IOException  
145     {
146         checkValid();
147         if( isDirectory() ) return null;
148         else
149         {
150             return m_accessor.getInputStream( this, m_resource );
151         }
152     }
153 
154     public boolean isValid()
155     {
156         return ( null != m_filesystem );
157     }
158 
159     /**
160      * Invalidate VFile and free all resources.
161      */
162     protected void invalidate()
163     {
164         m_filesystem = null;
165         m_resource = null;
166         m_accessor = null;
167     }
168 
169     /**
170      * Helper to make sure VFile is valid before proceeding.
171      * It will throw an IOException if VFile invalid.
172      *
173      * @exception IOException if an error occurs
174      */
175     private void checkValid()
176         throws IOException  
177     {
178         if( !isValid() )
179         {
180             throw new IOException  ( "Invalid VFile" );
181         }
182     }
183 
184     /**
185      * Helper method to get parents filename.
186      *
187      * @return the parents filename.
188      */
189     private String   getParentsName()
190     { 
191         final int index = m_path.lastIndexOf( '/' );
192         if( -1 == index )
193         {
194             return m_path;
195         }
196         else
197         {
198             return m_path.substring( 0, index );
199         }
200     }
201 }
202
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags