net.sf.mmm.crypto.hash

Class HashCreatorImplCombined

java.lang.Object

net.sf.mmm.crypto.algorithm.AbstractSecurityAlgorithm

net.sf.mmm.crypto.hash.HashCreatorImplCombined

All Implemented Interfaces:

CryptoAlgorithm, CryptoChunker, CryptoProcessor, HashCreator

public class HashCreatorImplCombined
extends AbstractSecurityAlgorithm
implements HashCreator

This is a simple implementation of HashCreator that only wraps MessageDigest.

Since:

1.0.0

Author:

Joerg Hohwiller (hohwille at users.sourceforge.net)

Field Summary

Fields

Modifier and Type	Field and Description
private HashCreator[]	generators

Constructor Summary

Constructors

Constructor and Description
HashCreatorImplCombined(HashCreator[] generators) The constructor.

Method Summary

Modifier and Type	Method and Description
String	getAlgorithm()
byte[]	hash(boolean reset)
void	reset() Will reset the internal state of this object.
void	update(byte[] input, int offset, int length)
OutputStream	wrapStream(OutputStream out) Creates a new OutputStream wraps the given OutputStream.

Methods inherited from class net.sf.mmm.crypto.algorithm.AbstractSecurityAlgorithm

creationFailedException, creationFailedException, creationFailedException, creationFailedException, getAlgorithm, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sf.mmm.crypto.hash.HashCreator

hash, hash, hash, hash, process, wrapStream

Methods inherited from interface net.sf.mmm.crypto.CryptoChunker

update, update

Methods inherited from interface net.sf.mmm.crypto.CryptoProcessor

process, process, process

Field Detail

generators

private final HashCreator[] generators

Constructor Detail

HashCreatorImplCombined

public HashCreatorImplCombined(HashCreator[] generators)

The constructor.

Parameters:

generators - the HashCreators to combine sequentially.

Method Detail

getAlgorithm

public String getAlgorithm()

Specified by:

getAlgorithm in interface CryptoAlgorithm

Returns:

the name of the underlying algorithm (e.g. "RSA", "NONEwithECDSA", etc.).

See Also:

Key.getAlgorithm(), Signature.getAlgorithm(), MessageDigest.getAlgorithm(), SecureRandom.getAlgorithm(), Cipher.getAlgorithm()

wrapStream

public OutputStream wrapStream(OutputStream out)

Description copied from interface: HashCreator

Creates a new OutputStream wraps the given OutputStream. It will automatically update all written data. After data has been written, you may call HashCreator.hash(boolean) to get the hash of the data. This method will not reset this hasher. Therefore any previous updated data will also influence the hash. The typical usage is to call this method once on a fresh instance of HashCreator, then write data to that stream and finally get the hash.

Specified by:

wrapStream in interface HashCreator

Parameters:

out - the OutputStream to wrap.

Returns:

a wrapped OutputStream.

See Also:

HashCreator.wrapStream(), DigestOutputStream

update

public void update(byte[] input,
                   int offset,
                   int length)

Specified by:

update in interface CryptoChunker

Parameters:

input - the next chunk of data.

offset - the index where to start reading data from input.

length - the number of bytes to read from input.

See Also:

MessageDigest.update(byte[], int, int), Signature.update(byte[], int, int)

hash

public byte[] hash(boolean reset)

Specified by:

hash in interface HashCreator

Parameters:

reset - - true if this HashCreator shall be reset after the hash calculation, false otherwise. A design problem of MessageDigest is that it automatically resets itself on hashing what prevents calculating intermediate hashes but also continue the hash calculation. This API allows to workaround this limitation.

Returns:

the calculated hash of the current data.

See Also:

MessageDigest.digest()

reset

public void reset()

Description copied from interface: CryptoProcessor

Will reset the internal state of this object. Please note that complex algorithms especially for Cryptor may not reusable. It is therefore preferable to always create a fresh instance for each cryptographic task.

Specified by:

reset in interface CryptoProcessor

See Also:

MessageDigest.reset()