edu.harvard.hul.ois.jhove

Class RAFInputStream

java.lang.Object

java.io.InputStream

edu.harvard.hul.ois.jhove.RAFInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

public class RAFInputStream
extends 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

Constructors

Constructor and Description
RAFInputStream(RandomAccessFile raf) Constructor with default buffer size.
RAFInputStream(RandomAccessFile raf, int bufferSize) Constructor with buffer size.

Method Summary

Methods

Modifier and Type	Method and Description
int	available() Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking.
long	getFilePos() Returns the current position in the file.
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, invalidating the buffer.
long	skip(long n) Skips some number of bytes.

Methods inherited from class java.io.InputStream

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(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(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 IOException

Reads a single byte from the file.

Specified by:

read in class InputStream

Throws:

IOException

read

public int read(byte[] b)
         throws 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 InputStream

Throws:

IOException

read

public int read(byte[] b,
       int off,
       int len)
         throws 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 InputStream

Throws:

IOException

skip

public long skip(long n)
          throws IOException

Skips some number of bytes.

Overrides:

skip in class InputStream

Returns:

the number of bytes actually skipped.

Throws:

IOException

available

public int available()
              throws IOException

Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking. A single read or skip of this many bytes will not block, but may read or skip fewer bytes.

Overrides:

available in class InputStream

Returns:

an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking, or 0 when it reaches the end of the input stream.

Throws:

IOException

getRAF

public RandomAccessFile getRAF()

Returns the RandomAccessFile object.

seek

public void seek(long offset)
          throws IOException

Positions the stream to a different point in the file, invalidating the buffer.

Throws:

IOException

getFilePos

public long getFilePos()
                throws 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:

IOException