Package org.duracloud.common.util

Class ChecksumUtil

java.lang.Object

org.duracloud.common.util.ChecksumUtil

public class ChecksumUtil
extends Object

A utility class for generating checksums. Beware this class it not threadsafe.

Author:

Daniel Bernstein

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ChecksumUtil.Algorithm	This class encapsulates the valid values for checksum algorithms.

Constructor Summary

Constructors

Constructor	Description
ChecksumUtil(ChecksumUtil.Algorithm alg)

Method Summary

Modifier and Type	Method	Description
static String	checksumBytesToString(byte[] digestBytes)	Converts a message digest byte array into a String based on the hex values appearing in the array.
static String	convertToBase64Encoding(String hexEncodedChecksum)	Converts a hex-encoded checksum (like that produced by the getChecksum and generateChecksum methods of this class) to a base64-encoded checksum
String	generateChecksum(File file)
String	generateChecksum(InputStream inStream)	This method generates checksum of content in arg stream.
String	generateChecksum(String string)	This method generates the checksum of a String and returns a hex-encoded String as the checksum value
String	generateChecksumBase64(String string)	This method generates the checksum of a String and returns a base64-encoded String as the checksum value
static String	getChecksum(DigestInputStream digestStream)	Determines the checksum value of a DigestInputStream's underlying stream after the stream has been read.
static byte[]	getChecksumBytes(DigestInputStream digestStream)	Determines the checksum value of a DigestInputStream's underlying stream after the stream has been read.
static byte[]	hexStringToByteArray(String s)
static DigestInputStream	wrapStream(InputStream inStream, ChecksumUtil.Algorithm algorithm)	Wraps an InputStream with a DigestInputStream in order to compute a checksum as the stream is being read.

Methods inherited from class java.lang.Object

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

Constructor Detail

ChecksumUtil

public ChecksumUtil(ChecksumUtil.Algorithm alg)

Method Detail

generateChecksum

public String generateChecksum(File file)
                        throws IOException

Throws:

IOException

generateChecksum

public String generateChecksum(InputStream inStream)

This method generates checksum of content in arg stream. Warning: this method is NOT threadsafe.

Parameters:

inStream - Content used as target of checksum.

Returns:

string representation of the generated checksum.

generateChecksum

public String generateChecksum(String string)

This method generates the checksum of a String and returns a hex-encoded String as the checksum value

Parameters:

string - Content used as target of checksum.

Returns:

string representation of the generated checksum using hex encoding

generateChecksumBase64

public String generateChecksumBase64(String string)

This method generates the checksum of a String and returns a base64-encoded String as the checksum value

Parameters:

string - Content used as target of checksum.

Returns:

string representation of the generated checksum using base64 encoding

wrapStream

public static DigestInputStream wrapStream(InputStream inStream,
                                           ChecksumUtil.Algorithm algorithm)

Wraps an InputStream with a DigestInputStream in order to compute a checksum as the stream is being read.

Parameters:

inStream - The stream to wrap

algorithm - The algorithm used to compute the digest

Returns:

The original stream wrapped as a DigestInputStream

getChecksum

public static String getChecksum(DigestInputStream digestStream)

Determines the checksum value of a DigestInputStream's underlying stream after the stream has been read.

Parameters:

digestStream -

Returns:

The checksum value of the stream's contents

getChecksumBytes

public static byte[] getChecksumBytes(DigestInputStream digestStream)

Determines the checksum value of a DigestInputStream's underlying stream after the stream has been read.

Parameters:

digestStream -

Returns:

The checksum value of the stream's contents

checksumBytesToString

public static String checksumBytesToString(byte[] digestBytes)

Converts a message digest byte array into a String based on the hex values appearing in the array.

hexStringToByteArray

public static byte[] hexStringToByteArray(String s)

convertToBase64Encoding

public static String convertToBase64Encoding(String hexEncodedChecksum)

Converts a hex-encoded checksum (like that produced by the getChecksum and generateChecksum methods of this class) to a base64-encoded checksum

Parameters:

hexEncodedChecksum - hex-encoded checksum

Returns:

base64-encoded checksum