Module java.base
Package java.security

## Class AlgorithmParametersSpi

- java.lang.Object
- - java.security.AlgorithmParametersSpi

-     public abstract class AlgorithmParametersSpi
      extends Object

  This class defines the Service Provider Interface (SPI) for the `AlgorithmParameters` class, which is used to manage algorithm parameters.

  All the abstract methods in this class must be implemented by each cryptographic service provider who wishes to supply parameter management for a particular algorithm.

  Since:
    1.2
  See Also:
    `AlgorithmParameters`, `AlgorithmParameterSpec`, `DSAParameterSpec`

- - ### Constructor Summary

    Constructors
    Constructor | Description
    --- | ---
    `AlgorithmParametersSpi()` |

  - ### Method Summary

    Modifier and Type | Method | Description
    --- | --- | ---
    `protected abstract byte[]` | `engineGetEncoded()` | Returns the parameters in their primary encoding format.
    `protected abstract byte[]` | `engineGetEncoded​(String format)` | Returns the parameters encoded in the specified format.
    `protected abstract <T extends AlgorithmParameterSpec> T` | `engineGetParameterSpec​(Class<T> paramSpec)` | Returns a (transparent) specification of this parameters object.
    `protected abstract void` | `engineInit​(byte[] params)` | Imports the specified parameters and decodes them according to the primary decoding format for parameters.
    `protected abstract void` | `engineInit​(byte[] params, String format)` | Imports the parameters from `params` and decodes them according to the specified decoding format.
    `protected abstract void` | `engineInit​(AlgorithmParameterSpec paramSpec)` | Initializes this parameters object using the parameters specified in `paramSpec`.
    `protected abstract String` | `engineToString()` | Returns a formatted string describing the parameters.

    - ### Methods declared in class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### AlgorithmParametersSpi

          public AlgorithmParametersSpi()

  - ### Method Detail

    - #### engineInit

          protected abstract void engineInit​(AlgorithmParameterSpec paramSpec)
                                      throws InvalidParameterSpecException

      Initializes this parameters object using the parameters specified in `paramSpec`.
      Parameters:
        `paramSpec` - the parameter specification.
      Throws:
        `InvalidParameterSpecException` - if the given parameter specification is inappropriate for the initialization of this parameter object.

    - #### engineInit

          protected abstract void engineInit​(byte[] params)
                                      throws IOException

      Imports the specified parameters and decodes them according to the primary decoding format for parameters. The primary decoding format for parameters is ASN.1, if an ASN.1 specification for this type of parameters exists.
      Parameters:
        `params` - the encoded parameters.
      Throws:
        `IOException` - on decoding errors

    - #### engineInit

          protected abstract void engineInit​(byte[] params,
                                             String format)
                                      throws IOException

      Imports the parameters from `params` and decodes them according to the specified decoding format. If `format` is null, the primary decoding format for parameters is used. The primary decoding format is ASN.1, if an ASN.1 specification for these parameters exists.
      Parameters:
        `params` - the encoded parameters.
        `format` - the name of the decoding format.
      Throws:
        `IOException` - on decoding errors

    - #### engineGetParameterSpec

          protected abstract <T extends AlgorithmParameterSpec> T engineGetParameterSpec​(Class<T> paramSpec)
                                                                                  throws InvalidParameterSpecException

      Returns a (transparent) specification of this parameters object. `paramSpec` identifies the specification class in which the parameters should be returned. It could, for example, be `DSAParameterSpec.class`, to indicate that the parameters should be returned in an instance of the `DSAParameterSpec` class.
      Type Parameters:
        `T` - the type of the parameter specification to be returned
      Parameters:
        `paramSpec` - the specification class in which the parameters should be returned.
      Returns:
        the parameter specification.
      Throws:
        `InvalidParameterSpecException` - if the requested parameter specification is inappropriate for this parameter object.

    - #### engineGetEncoded

          protected abstract byte[] engineGetEncoded()
                                              throws IOException

      Returns the parameters in their primary encoding format. The primary encoding format for parameters is ASN.1, if an ASN.1 specification for this type of parameters exists.
      Returns:
        the parameters encoded using their primary encoding format.
      Throws:
        `IOException` - on encoding errors.

    - #### engineGetEncoded

          protected abstract byte[] engineGetEncoded​(String format)
                                              throws IOException

      Returns the parameters encoded in the specified format. If `format` is null, the primary encoding format for parameters is used. The primary encoding format is ASN.1, if an ASN.1 specification for these parameters exists.
      Parameters:
        `format` - the name of the encoding format.
      Returns:
        the parameters encoded using the specified encoding scheme.
      Throws:
        `IOException` - on encoding errors.

    - #### engineToString

          protected abstract String engineToString()

      Returns a formatted string describing the parameters.
      Returns:
        a formatted string describing the parameters.