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ExemptionMechanismSpi (Java 2 Platform SE v1.4.1) - JDK 5 Documentation v1.4.1, Java 2 SDK 英文文档

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JavaTM 2 Platform
Std. Ed. v1.4.1
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javax.crypto
Class ExemptionMechanismSpi

java.lang.Object
  |
  +--javax.crypto.ExemptionMechanismSpi
public abstract class ExemptionMechanismSpi
extends Object

This class defines the Service Provider Interface (SPI) for the ExemptionMechanism 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 exemption mechanism.

Since:
1.4

Constructor Summary
ExemptionMechanismSpi()
           
 
Method Summary
protected abstract  byte[] engineGenExemptionBlob()
          Generates the exemption mechanism key blob.
protected abstract  int engineGenExemptionBlob(byte[] output, int outputOffset)
          Generates the exemption mechanism key blob, and stores the result in the output buffer, starting at outputOffset inclusive.
protected abstract  int engineGetOutputSize(int inputLen)
          Returns the length in bytes that an output buffer would need to be in order to hold the result of the next engineGenExemptionBlob operation, given the input length inputLen (in bytes).
protected abstract  void engineInit(Key key)
          Initializes this exemption mechanism with a key.
protected abstract  void engineInit(Key key, AlgorithmParameters params)
          Initializes this exemption mechanism with a key and a set of algorithm parameters.
protected abstract  void engineInit(Key key, AlgorithmParameterSpec params)
          Initializes this exemption mechanism with a key and a set of algorithm parameters.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ExemptionMechanismSpi

public ExemptionMechanismSpi()
Method Detail

engineGetOutputSize

protected abstract int engineGetOutputSize(int inputLen)
Returns the length in bytes that an output buffer would need to be in order to hold the result of the next engineGenExemptionBlob operation, given the input length inputLen (in bytes).

The actual output length of the next engineGenExemptionBlob call may be smaller than the length returned by this method.

Parameters:
inputLen - the input length (in bytes)
Returns:
the required output buffer size (in bytes)

engineInit

protected abstract void engineInit(Key key)
                            throws InvalidKeyException,
                                   ExemptionMechanismException
Initializes this exemption mechanism with a key.

If this exemption mechanism requires any algorithm parameters that cannot be derived from the given key, the underlying exemption mechanism implementation is supposed to generate the required parameters itself (using provider-specific default values); in the case that algorithm parameters must be specified by the caller, an InvalidKeyException is raised.

Parameters:
key - the key for this exemption mechanism
Throws:
InvalidKeyException - if the given key is inappropriate for this exemption mechanism.
ExemptionMechanismException - if problem(s) encountered in the process of initializing.

engineInit

protected abstract void engineInit(Key key,
                                   AlgorithmParameterSpec params)
                            throws InvalidKeyException,
                                   InvalidAlgorithmParameterException,
                                   ExemptionMechanismException
Initializes this exemption mechanism with a key and a set of algorithm parameters.

If this exemption mechanism requires any algorithm parameters and params is null, the underlying exemption mechanism implementation is supposed to generate the required parameters itself (using provider-specific default values); in the case that algorithm parameters must be specified by the caller, an InvalidAlgorithmParameterException is raised.

Parameters:
key - the key for this exemption mechanism
params - the algorithm parameters
Throws:
InvalidKeyException - if the given key is inappropriate for this exemption mechanism.
InvalidAlgorithmParameterException - if the given algorithm parameters are inappropriate for this exemption mechanism.
ExemptionMechanismException - if problem(s) encountered in the process of initializing.

engineInit

protected abstract void engineInit(Key key,
                                   AlgorithmParameters params)
                            throws InvalidKeyException,
                                   InvalidAlgorithmParameterException,
                                   ExemptionMechanismException
Initializes this exemption mechanism with a key and a set of algorithm parameters.

If this exemption mechanism requires any algorithm parameters and params is null, the underlying exemption mechanism implementation is supposed to generate the required parameters itself (using provider-specific default values); in the case that algorithm parameters must be specified by the caller, an InvalidAlgorithmParameterException is raised.

Parameters:
key - the key for this exemption mechanism
params - the algorithm parameters
Throws:
InvalidKeyException - if the given key is inappropriate for this exemption mechanism.
InvalidAlgorithmParameterException - if the given algorithm parameters are inappropriate for this exemption mechanism.
ExemptionMechanismException - if problem(s) encountered in the process of initializing.

engineGenExemptionBlob

protected abstract byte[] engineGenExemptionBlob()
                                          throws ExemptionMechanismException
Generates the exemption mechanism key blob.

Returns:
the new buffer with the result key blob.
Throws:
ExemptionMechanismException - if problem(s) encountered in the process of generating.

engineGenExemptionBlob

protected abstract int engineGenExemptionBlob(byte[] output,
                                              int outputOffset)
                                       throws ShortBufferException,
                                              ExemptionMechanismException
Generates the exemption mechanism key blob, and stores the result in the output buffer, starting at outputOffset inclusive.

If the output buffer is too small to hold the result, a ShortBufferException is thrown. In this case, repeat this call with a larger output buffer. Use engineGetOutputSize to determine how big the output buffer should be.

Parameters:
output - the buffer for the result
outputOffset - the offset in output where the result is stored
Returns:
the number of bytes stored in output
Throws:
ShortBufferException - if the given output buffer is too small to hold the result.
ExemptionMechanismException - if problem(s) encountered in the process of generating.
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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2002 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.