java.util.zip

Class CheckedOutputStream

java.lang.Object

java.io.OutputStream

java.io.FilterOutputStream

java.util.zip.CheckedOutputStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable

public class CheckedOutputStream
extends FilterOutputStream

The CheckedOutputStream class is used to maintain a running checksum of all data written to a stream. The purpose of this checksum is to establish data integrity, by publishing the checksum to other parties wanting to read the non corrupted data.

Field Summary

Fields inherited from class java.io.FilterOutputStream

out

Constructor Summary

Constructors

Constructor and Description
CheckedOutputStream(OutputStream os, Checksum cs) Constructs a new CheckedOutputStream on OutputStream os.

Method Summary

Modifier and Type	Method and Description
Checksum	getChecksum() Returns the checksum calculated on the stream read so far.
void	write(byte[] buf, int off, int nbytes) Writes n bytes of data from buf starting at offset off to the underlying stream.
void	write(int val) Writes the specified byte to the underlying stream.

Methods inherited from class java.io.FilterOutputStream

close, flush

Methods inherited from class java.io.OutputStream

nullOutputStream, write

Methods inherited from class java.lang.Object

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

Constructor Detail

CheckedOutputStream

public CheckedOutputStream(OutputStream os,
                           Checksum cs)

Constructs a new CheckedOutputStream on OutputStream os. The checksum is calculated using the algorithm implemented by csum.

Parameters:

os - the output stream to calculate checksum for.

cs - an entity implementing the checksum algorithm.

Method Detail

getChecksum

public Checksum getChecksum()

Returns the checksum calculated on the stream read so far.

Returns:

the updated checksum.

write

public void write(int val)
           throws IOException

Writes the specified byte to the underlying stream. The checksum is updated with val.

Overrides:

write in class FilterOutputStream

Parameters:

val - the data value to written to the output stream.

Throws:

IOException - if an IO error has occurred.

write

public void write(byte[] buf,
                  int off,
                  int nbytes)
           throws IOException

Writes n bytes of data from buf starting at offset off to the underlying stream. The checksum is updated with the bytes written.

Overrides:

write in class FilterOutputStream

Parameters:

buf - data written to the output stream.

off - the offset to start reading the data from buf written to the output stream.

nbytes - number of bytes to write to the output stream.

Throws:

IOException - if an IO error has occurred.