Checksum

public interface Checksum

java.util.zip.Checksum

Known indirect subclasses

Adler32	A class that can be used to compute the Adler-32 checksum of a data stream.
CRC32	A class that can be used to compute the CRC-32 of a data stream.
CRC32C	A class that can be used to compute the CRC-32C of a data stream.

An interface representing a data checksum.

Summary

Public methods
`abstract long`	`getValue()` Returns the current checksum value.
`abstract void`	`reset()` Resets the checksum to its initial value.
`default void`	`update(byte[] b)` Updates the current checksum with the specified array of bytes.
`default void`	`update(ByteBuffer buffer)` Updates the current checksum with the bytes from the specified buffer.
`abstract void`	`update(byte[] b, int off, int len)` Updates the current checksum with the specified array of bytes.
`abstract void`	`update(int b)` Updates the current checksum with the specified byte.

Public methods

getValue

Added in API level 1

public abstract long getValue ()

Returns the current checksum value.

Returns
`long`	the current checksum value

reset

Added in API level 1

public abstract void reset ()

Resets the checksum to its initial value.

update

Added in API level 34

public 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`	`byte`: the array of bytes to update the checksum with

Throws
`NullPointerException`	if `b` is `null`

update

Added in API level 34

public 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`	`ByteBuffer`: the ByteBuffer to update the checksum with

Throws
`NullPointerException`	if `buffer` is `null`

update

Added in API level 1

public abstract void update (byte[] b, 
                int off, 
                int len)

Updates the current checksum with the specified array of bytes.

Parameters
`b`	`byte`: the byte array to update the checksum with
`off`	`int`: the start offset of the data
`len`	`int`: the number of bytes to use for the update

update

Added in API level 1

public abstract void update (int b)

Updates the current checksum with the specified byte.

Parameters
`b`	`int`: the byte to update the checksum with