Package edu.wisc.library.ocfl.api.io

Class FixityCheckChannel

java.lang.Object

edu.wisc.library.ocfl.api.io.FixityCheckChannel

All Implemented Interfaces:

Closeable, AutoCloseable, ByteChannel, Channel, ReadableByteChannel, WritableByteChannel

public class FixityCheckChannel
extends Object
implements ByteChannel

A byte channel wrapper that preforms a fixity check on the bytes that pass through an underlying byte channel. After all of the channel's bytes have been read, checkFixity() should be called.

Constructor Summary

Constructors

Constructor	Description
FixityCheckChannel(ByteChannel delegate, DigestAlgorithm digestAlgorithm, String expectedDigestValue)	Constructs a new FixityCheckChannel
FixityCheckChannel(ByteChannel delegate, String digestAlgorithm, String expectedDigestValue)	Constructs a new FixityCheckChannel

Method Summary

Modifier and Type	Method	Description
void	checkFixity()	Performs a fixity check and throws an exception if the check fails.
void	close()
FixityCheckChannel	enableFixityCheck(boolean enabled)	By default fixity checking is enabled.
String	getExpectedDigestValue()
boolean	isOpen()
int	read(ByteBuffer dst)
int	write(ByteBuffer src)

Methods inherited from class java.lang.Object

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

Constructor Detail

FixityCheckChannel

public FixityCheckChannel(ByteChannel delegate,
                          DigestAlgorithm digestAlgorithm,
                          String expectedDigestValue)

Constructs a new FixityCheckChannel

Parameters:

delegate - the channel to wrap

digestAlgorithm - the digest algorithm to use

expectedDigestValue - the expected digest value

FixityCheckChannel

public FixityCheckChannel(ByteChannel delegate,
                          String digestAlgorithm,
                          String expectedDigestValue)

Constructs a new FixityCheckChannel

Parameters:

delegate - the channel to wrap

digestAlgorithm - the digest algorithm to use

expectedDigestValue - the expected digest value

Method Detail

checkFixity

public void checkFixity()

Performs a fixity check and throws an exception if the check fails. This should only be called after the entire contents of the stream has been read.

If the check is disabled, nothing happens

Throws:

FixityCheckException - when the actual digest value does not match the expected value

getExpectedDigestValue

public String getExpectedDigestValue()

Returns:

the expected digest value

enableFixityCheck

public FixityCheckChannel enableFixityCheck(boolean enabled)

By default fixity checking is enabled. Use this method to disable it, and prevent needless digest computation

Parameters:

enabled - if fixity should be checked

Returns:

this stream

read

public int read(ByteBuffer dst)
         throws IOException

Specified by:

read in interface ReadableByteChannel

Throws:

IOException

write

public int write(ByteBuffer src)
          throws IOException

Specified by:

write in interface WritableByteChannel

Throws:

IOException

isOpen

public boolean isOpen()

Specified by:

isOpen in interface Channel

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Channel

Specified by:

close in interface Closeable

Throws:

IOException