Java compact1, compact2, compact3 java.security Class MessageDigestSpi（JDK8）

Constructor Detail

• MessageDigestSpi

  public MessageDigestSpi()

Method Detail

• engineGetDigestLength

  protected int engineGetDigestLength()

  Returns the digest length in bytes.

  This concrete method has been added to this previously-defined abstract class. (For backwards compatibility, it cannot be abstract.)

  The default behavior is to return 0.

  This method may be overridden by a provider to return the digest length.

  Returns:

  the digest length in bytes.

  Since:

  1.2

• engineUpdate

  protected abstract void engineUpdate(byte input)

  Updates the digest using the specified byte.

  Parameters:

  input - the byte to use for the update.

• engineUpdate

  protected abstract void engineUpdate(byte[] input,
                                       int offset,
                                       int len)

  Updates the digest using the specified array of bytes, starting at the specified offset.

  Parameters:

  input - the array of bytes to use for the update.

  offset - the offset to start from in the array of bytes.

  len - the number of bytes to use, starting at offset.

• engineUpdate

  protected void engineUpdate(ByteBuffer input)

  Update the digest using the specified ByteBuffer. The digest is updated using the input.remaining() bytes starting at input.position(). Upon return, the buffer's position will be equal to its limit; its limit will not have changed.

  Parameters:

  input - the ByteBuffer

  Since:

  1.5

• engineDigest

  protected abstract byte[] engineDigest()

  Completes the hash computation by performing final operations such as padding. Once engineDigest has been called, the engine should be reset (see engineReset). Resetting is the responsibility of the engine implementor.

  Returns:

  the array of bytes for the resulting hash value.

• engineDigest

  protected int engineDigest(byte[] buf,
                             int offset,
                             int len)
                      throws DigestException

  Completes the hash computation by performing final operations such as padding. Once engineDigest has been called, the engine should be reset (see engineReset). Resetting is the responsibility of the engine implementor. This method should be abstract, but we leave it concrete for binary compatibility. Knowledgeable providers should override this method.

  Parameters:

  buf - the output buffer in which to store the digest

  offset - offset to start from in the output buffer

  len - number of bytes within buf allotted for the digest. Both this default implementation and the SUN provider do not return partial digests. The presence of this parameter is solely for consistency in our API's. If the value of this parameter is less than the actual digest length, the method will throw a DigestException. This parameter is ignored if its value is greater than or equal to the actual digest length.

  Returns:

  the length of the digest stored in the output buffer.

  Throws:

  DigestException - if an error occurs.

  Since:

  1.2

• engineReset

  protected abstract void engineReset()

  Resets the digest for further use.

• clone

  public Object clone()
               throws CloneNotSupportedException

  Returns a clone if the implementation is cloneable.

  Overrides:

  clone in class Object

  Returns:

  a clone if the implementation is cloneable.

  Throws:

  CloneNotSupportedException - if this is called on an implementation that does not support Cloneable.

  See Also:

  Cloneable