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

    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 Details

    • 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.