Package dk.netarkivet.common.utils

Class ChecksumCalculator

java.lang.Object

dk.netarkivet.common.utils.ChecksumCalculator

public final class ChecksumCalculator
extends Object

Calculates MD5 or SHA1 checksums on files using the built-in Java methods.

Field Summary

Fields

Modifier and Type	Field	Description
static String	MD5	Defines the MD5 checksum algorithm
static String	SHA1	Defines the SHA1 checksum algorithm

Constructor Summary

Constructors

Constructor	Description
ChecksumCalculator()

Method Summary

Modifier and Type	Method	Description
static String	calculateMd5(byte[] msg)	Generate an MD5 for a byte array.
static String	calculateMd5(File src)	Calculate MD5 for a file.
static String	calculateMd5(InputStream instream)	Calculates an MD5 digest on an InputStream, throwing away the data itself.
static String	calculateSha1(File src)	Calculate the SHA-1 DIGEST for a file.
static String	calculateSha1(InputStream instream)	Calculates an SHA-1 digest on an InputStream, throwing away the data itself.
static byte[]	digestFile(File src, String digestAlgorithm)
static byte[]	digestInputStream(InputStream instream, String algorithm)
static MessageDigest	getMessageDigest(String algorithm)	Get a MessageDigest for a specific algorithm.
static String	toHex(byte[] ba)	Converts a byte array to a hexstring.

Methods inherited from class java.lang.Object

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

Field Detail

MD5

public static final String MD5

Defines the MD5 checksum algorithm

See Also:

Constant Field Values

SHA1

public static final String SHA1

Defines the SHA1 checksum algorithm

See Also:

Constant Field Values

Constructor Detail

ChecksumCalculator

public ChecksumCalculator()

Method Detail

calculateMd5

public static String calculateMd5(File src)

Calculate MD5 for a file.

Parameters:

src - The file to calculate MD5 for.

Returns:

The MD5 sum of a file as a 32 characters long Hex string.

calculateSha1

public static String calculateSha1(File src)

Calculate the SHA-1 DIGEST for a file.

Parameters:

src - The file to calculate SHA-1 for.

Returns:

The SHA-1 sum of a file as a 32 characters long Hex string.

calculateMd5

public static String calculateMd5(InputStream instream)

Calculates an MD5 digest on an InputStream, throwing away the data itself. Throws Alert if there is an error reading from the stream

Parameters:

instream - An InputStream to calculate the MD5 digest on. The contents of the stream will be consumed by this call, but the stream will not be closed.

Returns:

The calculated MD5 digest as a string.

calculateSha1

public static String calculateSha1(InputStream instream)

Calculates an SHA-1 digest on an InputStream, throwing away the data itself. Throws Alert if there is an error reading from the stream

Parameters:

instream - An InputStream to calculate the SHA-1 digest on. The contents of the stream will be consumed by this call, but the stream will not be closed.

Returns:

The calculated SHA-1 digest as a string.

calculateMd5

public static String calculateMd5(byte[] msg)

Generate an MD5 for a byte array.

Parameters:

msg - The given bytearray

Returns:

the MD5 for a byte array

toHex

public static String toHex(byte[] ba)

Converts a byte array to a hexstring.

Parameters:

ba - the bytearray to be converted

Returns:

ba converted to a hexstring

digestFile

public static byte[] digestFile(File src,
                                String digestAlgorithm)

digestInputStream

public static byte[] digestInputStream(InputStream instream,
                                       String algorithm)

getMessageDigest

public static MessageDigest getMessageDigest(String algorithm)

Get a MessageDigest for a specific algorithm.

Parameters:

algorithm - a specific MessageDigest algorithm.

Returns:

a MessageDigest for a specific algorithm