iaik.smime
Class SharedFileInputStream

java.lang.Object
  java.io.InputStream
      java.io.FilterInputStream
          java.io.BufferedInputStream
              iaik.smime.SharedFileInputStream

All Implemented Interfaces:

java.io.Closeable, javax.mail.internet.SharedInputStream

public class SharedFileInputStream
extends java.io.BufferedInputStream
implements javax.mail.internet.SharedInputStream

A SharedFileInputStream for reading data from a file.

This class implements the JavaMail SharedInputStream interface for creating substreams by calls to method newStream that read data from the same underlying file.

When creating a SharedFileInputStream the file from which to read has to be specified:

 File file = ...;
 SharedFileInputStream sfi = new SharedFileInputStream(file);
 

This class uses a special RandomAccessFileInputStream to read the data from a basic file that is accessed through a RandomAccessFile. Anytime when method newStream is called, a new substream is created to read data from the same underlying file.

See Also:

SharedInputStream

Field Summary

Fields inherited from class java.io.BufferedInputStream

buf, count, marklimit, markpos, pos

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

SharedFileInputStream(java.io.File file)
Creates a SharedFileInputStream for reading from the given file.

SharedFileInputStream(java.io.File file, int bufSize)
Creates a SharedFileInputStream for reading from the given file.

Method Summary

int	available() Gets the number of bytes that can be read from this stream without blocking.
void	close() Closes this input stream.
protected void	finalize() Performs finalization.
long	getPosition() Gets the current position of the stream as offset from the start position.
void	mark(int readlimit) Marks the current position in this input stream to start reading from it when method reset is called.
boolean	markSupported() Asks whether this input stream does support mark and reset.
java.io.InputStream	newStream(long start, long end) Gets a new SharedInputStream as sub-stream from this InputStream.
int	read() Reads one byte from this stream.
int	read(byte[] b, int off, int len) Reads up to len bytes from this stream.
void	reset() Resets the stream to the position that has been previously set by calling method mark.
long	skip(long n) Skips up to n bytes of data.

Methods inherited from class java.io.FilterInputStream

read

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SharedFileInputStream

public SharedFileInputStream(java.io.File file)
                      throws java.io.IOException

Creates a SharedFileInputStream for reading from the given file.

Parameters:

file - the file from which to read

Throws:

java.io.IOException - if an I/O error occurs

SharedFileInputStream

public SharedFileInputStream(java.io.File file,
                             int bufSize)
                      throws java.io.IOException

Creates a SharedFileInputStream for reading from the given file.

Parameters:

file - the file from which to read

bufSize - the size of the internal buffer to be used

Throws:

java.io.IOException - if an I/O error occurs

Method Detail

read

public int read()
         throws java.io.IOException

Reads one byte from this stream.

Overrides:

read in class java.io.BufferedInputStream

Returns:

the byte read from this stream or -1 if the end of the stream has been reached

Throws:

java.io.IOException

read

public int read(byte[] b,
                int off,
                int len)
         throws java.io.IOException

Reads up to len bytes from this stream.

Overrides:

read in class java.io.BufferedInputStream

Parameters:

b - the byte array into which to read the data

off - the start offset in b

len - the maximum number of bytes to read.

Returns:

the number of bytes read from the stream or -1 if the end of the stream has been reached

Throws:

java.io.IOException - if an I/O error occurs while reading from the stream

skip

public long skip(long n)
          throws java.io.IOException

Skips up to n bytes of data.

Overrides:

skip in class java.io.BufferedInputStream

Parameters:

n - the number of bytes to skip

Returns:

the number of bytes actually skipped

Throws:

java.io.IOException - error occurs while skipping

available

public int available()
              throws java.io.IOException

Gets the number of bytes that can be read from this stream without blocking.

Overrides:

available in class java.io.BufferedInputStream

Returns:

the number of bytes that can be read from this stream without blocking

Throws:

java.io.IOException - if an I/O error occurs.

mark

public void mark(int readlimit)

Marks the current position in this input stream to start reading from it when method reset is called.

Overrides:

mark in class java.io.BufferedInputStream

Parameters:

readlimit - the number of bytes that can be read before mark becomes invalid

reset

public void reset()

Resets the stream to the position that has been previously set by calling method mark.

Overrides:

reset in class java.io.BufferedInputStream

markSupported

public boolean markSupported()

Asks whether this input stream does support mark and reset.

Overrides:

markSupported in class java.io.BufferedInputStream

Returns:

true since this stream supports mark/reset

close

public void close()
           throws java.io.IOException

Closes this input stream.

Specified by:

close in interface java.io.Closeable

Overrides:

close in class java.io.BufferedInputStream

Throws:

java.io.IOException - if an I/O error occurs when closing the stream.

getPosition

public long getPosition()

Gets the current position of the stream as offset from the start position.

Specified by:

getPosition in interface javax.mail.internet.SharedInputStream

Returns:

the current read position in the stream

newStream

public java.io.InputStream newStream(long start,
                                     long end)

Gets a new SharedInputStream as sub-stream from this InputStream.

Specified by:

newStream in interface javax.mail.internet.SharedInputStream

Parameters:

start - the start position in the current stream

end - the end position (+1) in the current stream; -1 if the new stream shall end at the same position as this stream

Returns:

the new stream sub stream

finalize

protected void finalize()
                 throws java.lang.Throwable

Performs finalization.

Overrides:

finalize in class java.lang.Object

Throws:

java.lang.Throwable - if an error occurs during finalization