Package nl.knaw.dans.bagit.hash

Class Hasher

java.lang.Object

nl.knaw.dans.bagit.hash.Hasher

public final class Hasher
extends Object

Convenience class for generating a HEX formatted string of the checksum hash.

Field Summary

Fields

Modifier and Type	Field	Description
private static final int	_64_KB
private static final int	CHUNK_SIZE
private static final org.slf4j.Logger	logger
private static final ResourceBundle	messages

Constructor Summary

Constructors

Modifier	Constructor	Description
private	Hasher()

Method Summary

Modifier and Type	Method	Description
private static void	addMessageDigestHashToManifest(Path path, Map<Manifest,MessageDigest> manifestToMessageDigestMap)
static Map<Manifest,MessageDigest>	createManifestToMessageDigestMap(Collection<SupportedAlgorithm> algorithms)	create a mapping between Manifest and MessageDigest for each each supplied SupportedAlgorithm
private static String	formatMessageDigest(MessageDigest messageDigest)
static String	hash(Path path, MessageDigest messageDigest)	Create a HEX formatted string checksum hash of the file
static void	hash(Path path, Map<Manifest,MessageDigest> manifestToMessageDigestMap)	Update the Manifests with the file's hash
(package private) static void	updateMessageDigests(Path path, Collection<MessageDigest> messageDigests)

Methods inherited from class java.lang.Object

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

Field Details

logger

private static final org.slf4j.Logger logger

_64_KB

private static final int _64_KB

See Also:

• Constant Field Values

CHUNK_SIZE

private static final int CHUNK_SIZE

See Also:

• Constant Field Values

messages

private static final ResourceBundle messages

Constructor Details

Hasher

private Hasher()

Method Details

hash

public static String hash(Path path,
 MessageDigest messageDigest)
                   throws IOException

Create a HEX formatted string checksum hash of the file

Parameters:

path - the Path (file) to hash

messageDigest - the MessageDigest object representing the hashing algorithm

Returns:

the hash as a hex formated string

Throws:

IOException - if there is a problem reading the file

hash

public static void hash(Path path,
 Map<Manifest,MessageDigest> manifestToMessageDigestMap)
                 throws IOException

Update the Manifests with the file's hash

Parameters:

path - the Path (file) to hash

manifestToMessageDigestMap - the map between Manifest and MessageDigest

Throws:

IOException - if there is a problem reading the file

updateMessageDigests

static void updateMessageDigests(Path path,
 Collection<MessageDigest> messageDigests)
                          throws IOException

Throws:

IOException

addMessageDigestHashToManifest

private static void addMessageDigestHashToManifest(Path path,
 Map<Manifest,MessageDigest> manifestToMessageDigestMap)

formatMessageDigest

private static String formatMessageDigest(MessageDigest messageDigest)

createManifestToMessageDigestMap

public static Map<Manifest,MessageDigest> createManifestToMessageDigestMap(Collection<SupportedAlgorithm> algorithms)
                                                                    throws NoSuchAlgorithmException

create a mapping between Manifest and MessageDigest for each each supplied SupportedAlgorithm

Parameters:

algorithms - the SupportedAlgorithm that you which to map to MessageDigest

Returns:

mapping between Manifest and MessageDigest

Throws:

NoSuchAlgorithmException - if MessageDigest doesn't support the algorithm