Module java.base
Package java.util.zip

Interface Checksum

  • All Known Implementing Classes:
    Adler32, CRC32, CRC32C
    public interface Checksum
    An interface representing a data checksum.
    Since:
    1.1

    • Method Summary

      All Methods Instance Methods Abstract Methods Default Methods 
      Modifier and Type Method Description
      long getValue()
      Returns the current checksum value.
      void reset()
      Resets the checksum to its initial value.
      default void update​(byte[] b)
      Updates the current checksum with the specified array of bytes.
      void update​(byte[] b, int off, int len)
      Updates the current checksum with the specified array of bytes.
      void update​(int b)
      Updates the current checksum with the specified byte.
      default void update​(ByteBuffer buffer)
      Updates the current checksum with the bytes from the specified buffer.

    • Method Detail

      • update

        void update​(int b)
        Updates the current checksum with the specified byte.
        Parameters:
        b - the byte to update the checksum with

      • update

        default void update​(byte[] b)
        Updates the current checksum with the specified array of bytes.
        Implementation Requirements:
        This default implementation is equal to calling update(b, 0, b.length).
        Parameters:
        b - the array of bytes to update the checksum with
        Throws:
        NullPointerException - if b is null
        Since:
        9

      • update

        void update​(byte[] b,
            int off,
            int len)
        Updates the current checksum with the specified array of bytes.
        Parameters:
        b - the byte array to update the checksum with
        off - the start offset of the data
        len - the number of bytes to use for the update

      • update

        default void update​(ByteBuffer buffer)
        Updates the current checksum with the bytes from the specified buffer. The checksum is updated with the remaining bytes in the buffer, starting at the buffer's position. Upon return, the buffer's position will be updated to its limit; its limit will not have been changed.
        API Note:
        For best performance with DirectByteBuffer and other ByteBuffer implementations without a backing array implementers of this interface should override this method.
        Implementation Requirements:
        The default implementation has the following behavior.
        For ByteBuffers backed by an accessible byte array. 
        
 update(buffer.array(),
        buffer.position() + buffer.arrayOffset(),
        buffer.remaining());
        For ByteBuffers not backed by an accessible byte array. 
        
 byte[] b = new byte[Math.min(buffer.remaining(), 4096)];
 while (buffer.hasRemaining()) {
     int length = Math.min(buffer.remaining(), b.length);
     buffer.get(b, 0, length);
     update(b, 0, length);
 }
        Parameters:
        buffer - the ByteBuffer to update the checksum with
        Throws:
        NullPointerException - if buffer is null
        Since:
        9

      • getValue

        long getValue()
        Returns the current checksum value.
        Returns:
        the current checksum value

      • reset

        void reset()
        Resets the checksum to its initial value.