edu.harvard.hul.ois.jhove
Class RAFInputStream

java.lang.Object
  java.io.InputStream
      edu.harvard.hul.ois.jhove.RAFInputStream

All Implemented Interfaces:

java.io.Closeable

public class RAFInputStream
extends java.io.InputStream

An InputStream layered on top of a RandomAccessFile. This is useful for a Module which has requirements that force it to use a RandomAccessFile, but is usually accessed sequentially. An RAFInputStream maintains its own position information in the file, so multiple RAFInputStreams in the same file will work without interference. However, this class is not thread-safe.

Author:

Gary McGath

Constructor Summary

RAFInputStream(java.io.RandomAccessFile raf)
Constructor with default buffer size.

RAFInputStream(java.io.RandomAccessFile raf, int bufferSize)
Constructor with buffer size.

Method Summary

long	getFilePos() Returns the current position in the file.
java.io.RandomAccessFile	getRAF() Returns the RandomAccessFile object.
int	read() Reads a single byte from the file.
int	read(byte[] b) Reads some number of bytes from the input stream and stores them into the buffer array b.
int	read(byte[] b, int off, int len) Reads up to len bytes of data from the input stream into an array of bytes.
void	seek(long offset) Positions the stream to a different point in the file.
long	skip(long n) Skips some number of bytes.

Methods inherited from class java.io.InputStream

available, close, mark, markSupported, reset

Methods inherited from class java.lang.Object

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

Constructor Detail

RAFInputStream

public RAFInputStream(java.io.RandomAccessFile raf)

Constructor with default buffer size. The stream starts at the current position of the RandomAccessFile.

Parameters:

raf - The file on which the stream is to be based.

RAFInputStream

public RAFInputStream(java.io.RandomAccessFile raf,
                      int bufferSize)

Constructor with buffer size. The stream starts at the current position of the RandomAccessFile.

Parameters:

raf - The file on which the stream is to be based.

bufferSize - The buffer size to be used. If less than or equal to 0, the default buffer size is used.

Method Detail

read

public int read()
         throws java.io.IOException

Reads a single byte from the file.

Specified by:

read in class java.io.InputStream

Throws:

java.io.IOException

read

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

Reads some number of bytes from the input stream and stores them into the buffer array b. The number of bytes actually read is returned as an integer.

Overrides:

read in class java.io.InputStream

Throws:

java.io.IOException

read

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

Reads up to len bytes of data from the input stream into an array of bytes. An attempt is made to read as many as len bytes, but a smaller number may be read, possibly zero. The number of bytes actually read is returned as an integer.

Overrides:

read in class java.io.InputStream

Throws:

java.io.IOException

skip

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

Skips some number of bytes.

Overrides:

skip in class java.io.InputStream

Returns:

The number of bytes actually skipped.

Throws:

java.io.IOException

getRAF

public java.io.RandomAccessFile getRAF()

Returns the RandomAccessFile object.

seek

public void seek(long offset)
          throws java.io.IOException

Positions the stream to a different point in the file. This invalidates the buffer.

Throws:

java.io.IOException

getFilePos

public long getFilePos()
                throws java.io.IOException

Returns the current position in the file. What is reported is the position of the byte in the file which was last extracted from the buffer.

Throws:

java.io.IOException