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1
17
18 package org.apache.james.mailrepository.filepair;
19
20 import java.io.BufferedInputStream  ;
21 import java.io.File ;
22 import java.io.FileInputStream ;
23 import java.io.IOException ;
24 import java.io.InputStream ;
25
26
28 public class ResettableFileInputStream
29 extends InputStream
30 {
31 protected static final int DEFAULT_BUFFER_SIZE = 1024;
32
33 protected final String m_filename;
34 protected int m_bufferSize;
35 protected InputStream m_inputStream;
36 protected long m_position;
37 protected long m_mark;
38 protected boolean m_isMarkSet;
39
40 public ResettableFileInputStream( final File file )
41 throws IOException
42 {
43 this( file.getCanonicalPath() );
44 }
45
46 public ResettableFileInputStream( final String filename )
47 throws IOException
48 {
49 this( filename, DEFAULT_BUFFER_SIZE );
50 }
51
52 public ResettableFileInputStream( final String filename, final int bufferSize )
53 throws IOException
54 {
55 m_bufferSize = bufferSize;
56 m_filename = filename;
57 m_position = 0;
58
59 m_inputStream = newStream();
60 }
61
62 public void mark( final int readLimit )
63 {
64 m_isMarkSet = true;
65 m_mark = m_position;
66 m_inputStream.mark( readLimit );
67 }
68
69 public boolean markSupported()
70 {
71 return true;
72 }
73
74 public void reset()
75 throws IOException
76 {
77 if( !m_isMarkSet )
78 {
79 throw new IOException ( "Unmarked Stream" );
80 }
81 try
82 {
83 m_inputStream.reset();
84 }
85 catch( final IOException ioe )
86 {
87 try
88 {
89 m_inputStream.close();
90 m_inputStream = newStream();
91 m_inputStream.skip( m_mark );
92 m_position = m_mark;
93 }
94 catch( final Exception e )
95 {
96 throw new IOException ( "Cannot reset current Stream: " + e.getMessage() );
97 }
98 }
99 }
100
101 protected InputStream newStream()
102 throws IOException
103 {
104 return new BufferedInputStream ( new FileInputStream ( m_filename ), m_bufferSize );
105 }
106
107 public int available()
108 throws IOException
109 {
110 return m_inputStream.available();
111 }
112
113 public void close() throws IOException
114 {
115 m_inputStream.close();
116 }
117
118 public int read() throws IOException
119 {
120 m_position++;
121 return m_inputStream.read();
122 }
123
124 public int read( final byte[] bytes, final int offset, final int length )
125 throws IOException
126 {
127 final int count = m_inputStream.read( bytes, offset, length );
128 m_position += count;
129 return count;
130 }
131
132 public long skip( final long count )
133 throws IOException
134 {
135 m_position += count;
136 return m_inputStream.skip( count );
137 }
138 }
139 |
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