ome.util.checksum

Interface ChecksumProvider

All Known Implementing Classes:

AbstractChecksumProvider, Adler32ChecksumProviderImpl, CRC32ChecksumProviderImpl, FileSizeChecksumProviderImpl, MD5ChecksumProviderImpl, Murmur128ChecksumProviderImpl, Murmur32ChecksumProviderImpl, SHA1ChecksumProviderImpl

public interface ChecksumProvider

An interface producing checksums or message digests (depending on the implementing class) of a given type of input. The object's internal state represents the current checksum value and each call to putBytes() updates this object's internal state. It is the callers responsibility to make sure calls to putFile(String) are not intermixed with putBytes(). This object can only return a checksum for a file or byte structure, never both.
Inside the ome.util.checksum package, the term checksum is understood as an "umbrella" term covering checksums, message digests and hashes.

Since:

4.4.7

Author:

Blazej Pindelski, bpindelski at dundee.ac.uk

Method Summary

Modifier and Type	Method and Description
byte[]	checksumAsBytes() Returns a byte array representation of the calculated checksum.
java.lang.String	checksumAsString() Returns a String representing the checksum in hex form.
ChecksumProvider	putBytes(byte[] byteArray) Updates the internal checksum value with data from a byte array.
ChecksumProvider	putBytes(byte[] byteArray, int offset, int length) Updates the internal checksum value with data from a chunk of a byte array.
ChecksumProvider	putBytes(java.nio.ByteBuffer byteBuffer) Updates the internal checksum value with data from a byte buffer.
ChecksumProvider	putFile(java.lang.String filePath) Updates the internal checksum value with data from a file identified by a path.

Method Detail

putBytes

ChecksumProvider putBytes(byte[] byteArray)

Updates the internal checksum value with data from a byte array. If the array is null, throws NPE. Note that, although checksum results are consistent for any given hash function and byte array, different hash functions may calculate different checksums for an empty array despite its lack of content.

Parameters:

byteArray - The input byte array.

Returns:

ChecksumProvider

putBytes

ChecksumProvider putBytes(byte[] byteArray,
                          int offset,
                          int length)

Updates the internal checksum value with data from a chunk of a byte array. First byte read is byteArray[offset], last byte read is byteArray[offset + length - 1]. If the array is null, throws NPE. Throws IOOB if indexes are invalid. Note that, although checksum results are consistent for any given hash function and byte array, different hash functions may calculate different checksums for an empty array despite its lack of content.

Parameters:

byteArray - The input byte array.

offset - The offset in the byte array at which to start putting bytes.

length - The number of bytes to put, starting from the offset.

Returns:

ChecksumProvider

putBytes

ChecksumProvider putBytes(java.nio.ByteBuffer byteBuffer)

Updates the internal checksum value with data from a byte buffer. If the array underlying the byte buffer is not accessible, throws an IllegalArgumentException.

Parameters:

byteBuffer - The input byte buffer.

Returns:

ChecksumProvider

putFile

ChecksumProvider putFile(java.lang.String filePath)

Updates the internal checksum value with data from a file identified by a path. Throws a RuntimeException in a case of an IO error. Input previous to this method does not affect the calculated checksum.

Parameters:

filePath - String representing the absolute file path.

Returns:

ChecksumProvider

checksumAsBytes

byte[] checksumAsBytes()

Returns a byte array representation of the calculated checksum. Subsequent calls to this method will return the same object state. After calling this method any invocation of the mutating methods (put*) will cause it to throw IllegalStateException.

Returns:

byte[] The checksum in a byte array.

checksumAsString

java.lang.String checksumAsString()

Returns a String representing the checksum in hex form. Subsequent calls to this method will return the same object state. After calling this method any invocation of the mutating methods (put*) will cause it to throw IllegalStateException.

Returns:

String The hexadecimal value of the checksum.