Java in a Nutshell, 5th Edition

Name

Checksum

Synopsis

This interface defines the methods required to compute a checksum on a stream of data. The checksum is computed based on the bytes of data supplied by the update( ) methods; the current value of the checksum can be obtained at any time with the getValue( ) method. reset( ) resets the checksum to its default value; use this method before beginning a new stream of data. The checksum value computed by a Checksum object and returned through the getValue( ) method must fit into a long value. Therefore, this interface is not suitable for the cryptographic checksum algorithms used in cryptography and security. The classes CheckedInputStream and CheckedOutputStream provide a higher-level API for computing a checksum on a stream of data. See also java.security.MessageDigest.

public interface Checksum {
// Public Instance Methods
     long getValue( );  
     void reset( );  
     void update(int b);  
     void update(byte[ ] b, int off, int len);  
}

Implementations

Adler32, CRC32

Passed To

CheckedInputStream.CheckedInputStream( ), CheckedOutputStream.CheckedOutputStream( )

Returned By

CheckedInputStream.getChecksum( ), CheckedOutputStream.getChecksum( )