MacSpi (Java Platform SE 7 b138)

java.lang.Object
- javax.crypto.MacSpi

```
public abstract class MacSpi
extends Object
```
This class defines the Service Provider Interface (SPI) for the Mac class. All the abstract methods in this class must be implemented by each cryptographic service provider who wishes to supply the implementation of a particular MAC algorithm.
Implementations are free to implement the Cloneable interface.

Since:

1.4

Constructor Summary

Constructors
Constructor and Description

MacSpi()

Constructors
Constructor and Description
`MacSpi()`

Method Summary

Methods
Modifier and Type	Method and Description
`Object`	`clone()` Returns a clone if the implementation is cloneable.
`protected abstract byte[]`	`engineDoFinal()` Completes the MAC computation and resets the MAC for further use, maintaining the secret key that the MAC was initialized with.
`protected abstract int`	`engineGetMacLength()` Returns the length of the MAC in bytes.
`protected abstract void`	`engineInit(Key key, AlgorithmParameterSpec params)` Initializes the MAC with the given (secret) key and algorithm parameters.
`protected abstract void`	`engineReset()` Resets the MAC for further use, maintaining the secret key that the MAC was initialized with.
`protected abstract void`	`engineUpdate(byte input)` Processes the given byte.
`protected abstract void`	`engineUpdate(byte[] input, int offset, int len)` Processes the first `len` bytes in `input`, starting at `offset` inclusive.
`protected void`	`engineUpdate(ByteBuffer input)` Processes `input.remaining()` bytes in the ByteBuffer `input`, starting at `input.position()`.

Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - MacSpi
```
public MacSpi()
```
- Method Detail
  - engineGetMacLength
```
protected abstract int engineGetMacLength()
```
    Returns the length of the MAC in bytes.
    
    Returns:
    the MAC length in bytes.
  - engineInit
```
protected abstract void engineInit(Key key,
              AlgorithmParameterSpec params)
                            throws InvalidKeyException,
                                   InvalidAlgorithmParameterException
```
    Initializes the MAC with the given (secret) key and algorithm parameters.
    
    Parameters:
    key - the (secret) key.
    params - the algorithm parameters.
    
    Throws:
    
    InvalidKeyException - if the given key is inappropriate for initializing this MAC.
    
    InvalidAlgorithmParameterException - if the given algorithm parameters are inappropriate for this MAC.
  - engineUpdate
```
protected abstract void engineUpdate(byte input)
```
    Processes the given byte.
    
    Parameters:
    input - the input byte to be processed.
  - engineUpdate
```
protected abstract void engineUpdate(byte[] input,
                int offset,
                int len)
```
    Processes the first len bytes in input, starting at offset inclusive.
    
    Parameters:
    input - the input buffer.
    offset - the offset in input where the input starts.
    len - the number of bytes to process.
  - engineUpdate
```
protected void engineUpdate(ByteBuffer input)
```
    Processes input.remaining() bytes in the ByteBuffer input, starting at input.position(). Upon return, the buffer's position will be equal to its limit; its limit will not have changed.
    Subclasses should consider overriding this method if they can process ByteBuffers more efficiently than byte arrays.
    
    Parameters:
    input - the ByteBuffer
    Since:
    
    1.5
  - engineDoFinal
```
protected abstract byte[] engineDoFinal()
```
    Completes the MAC computation and resets the MAC for further use, maintaining the secret key that the MAC was initialized with.
    
    Returns:
    the MAC result.
  - engineReset
```
protected abstract void engineReset()
```
    Resets the MAC for further use, maintaining the secret key that the MAC was initialized with.
  - 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

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For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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DRAFT ea-b138

Class MacSpi

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

MacSpi

Method Detail

engineGetMacLength

engineInit

engineUpdate

engineUpdate

engineUpdate

engineDoFinal

engineReset

clone