An AlgorithmParameters
object for managing the parameters
for a particular algorithm can be obtained by
calling one of the getInstance
factory methods
(static methods that return instances of a given class).
Once an AlgorithmParameters
object is obtained, it must be
initialized via a call to init
, using an appropriate parameter
specification or parameter encoding.
A transparent parameter specification is obtained from an
AlgorithmParameters
object via a call to
getParameterSpec
, and a byte encoding of the parameters is
obtained via a call to getEncoded
.
Every implementation of the Java platform is required to support the
following standard AlgorithmParameters
algorithms:
AES
DESede
DiffieHellman
DSA
- Since:
- 1.2
- See Also:
-
Constructor Summary
ModifierConstructorDescriptionprotected
AlgorithmParameters
(AlgorithmParametersSpi paramSpi, Provider provider, String algorithm) Creates anAlgorithmParameters
object. -
Method Summary
Modifier and TypeMethodDescriptionfinal String
Returns the name of the algorithm associated with this parameter object.final byte[]
Returns the parameters in their primary encoding format.final byte[]
getEncoded
(String format) Returns the parameters encoded in the specified scheme.static AlgorithmParameters
getInstance
(String algorithm) Returns a parameter object for the specified algorithm.static AlgorithmParameters
getInstance
(String algorithm, String provider) Returns a parameter object for the specified algorithm.static AlgorithmParameters
getInstance
(String algorithm, Provider provider) Returns a parameter object for the specified algorithm.final <T extends AlgorithmParameterSpec>
TgetParameterSpec
(Class<T> paramSpec) Returns a (transparent) specification of this parameter object.final Provider
Returns the provider of this parameter object.final void
init
(byte[] params) Imports the specified parameters and decodes them according to the primary decoding format for parameters.final void
Imports the parameters fromparams
and decodes them according to the specified decoding scheme.final void
init
(AlgorithmParameterSpec paramSpec) Initializes this parameter object using the parameters specified inparamSpec
.final String
toString()
Returns a formatted string describing the parameters.
-
Constructor Details
-
AlgorithmParameters
Creates anAlgorithmParameters
object.- Parameters:
paramSpi
- the delegateprovider
- the provideralgorithm
- the algorithm
-
-
Method Details
-
getAlgorithm
Returns the name of the algorithm associated with this parameter object.- Returns:
- the algorithm name.
-
getInstance
Returns a parameter object for the specified algorithm.This method traverses the list of registered security providers, starting with the most preferred provider. A new
AlgorithmParameters
object encapsulating theAlgorithmParametersSpi
implementation from the first provider that supports the specified algorithm is returned.Note that the list of registered providers may be retrieved via the
Security.getProviders()
method.The returned parameter object must be initialized via a call to
init
, using an appropriate parameter specification or parameter encoding.- Implementation Note:
- The JDK Reference Implementation additionally uses the
jdk.security.provider.preferred
Security
property to determine the preferred provider order for the specified algorithm. This may be different from the order of providers returned bySecurity.getProviders()
. - Parameters:
algorithm
- the name of the algorithm requested. See the AlgorithmParameters section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names.- Returns:
- the new parameter object
- Throws:
NoSuchAlgorithmException
- if noProvider
supports anAlgorithmParametersSpi
implementation for the specified algorithmNullPointerException
- ifalgorithm
isnull
- See Also:
-
getInstance
public static AlgorithmParameters getInstance(String algorithm, String provider) throws NoSuchAlgorithmException, NoSuchProviderException Returns a parameter object for the specified algorithm.A new
AlgorithmParameters
object encapsulating theAlgorithmParametersSpi
implementation from the specified provider is returned. The specified provider must be registered in the security provider list.Note that the list of registered providers may be retrieved via the
Security.getProviders()
method.The returned parameter object must be initialized via a call to
init
, using an appropriate parameter specification or parameter encoding.- Parameters:
algorithm
- the name of the algorithm requested. See the AlgorithmParameters section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names.provider
- the name of the provider.- Returns:
- the new parameter object
- Throws:
IllegalArgumentException
- if the provider name isnull
or emptyNoSuchAlgorithmException
- if anAlgorithmParametersSpi
implementation for the specified algorithm is not available from the specified providerNoSuchProviderException
- if the specified provider is not registered in the security provider listNullPointerException
- ifalgorithm
isnull
- See Also:
-
getInstance
public static AlgorithmParameters getInstance(String algorithm, Provider provider) throws NoSuchAlgorithmException Returns a parameter object for the specified algorithm.A new
AlgorithmParameters
object encapsulating theAlgorithmParametersSpi
implementation from the specified provider is returned. Note that the specified provider does not have to be registered in the provider list.The returned parameter object must be initialized via a call to
init
, using an appropriate parameter specification or parameter encoding.- Parameters:
algorithm
- the name of the algorithm requested. See the AlgorithmParameters section in the Java Security Standard Algorithm Names Specification for information about standard algorithm names.provider
- the name of the provider.- Returns:
- the new parameter object
- Throws:
IllegalArgumentException
- if the provider isnull
NoSuchAlgorithmException
- if anAlgorithmParameterGeneratorSpi
implementation for the specified algorithm is not available from the specifiedProvider
objectNullPointerException
- ifalgorithm
isnull
- Since:
- 1.4
- See Also:
-
getProvider
Returns the provider of this parameter object.- Returns:
- the provider of this parameter object
-
init
Initializes this parameter object using the parameters specified inparamSpec
.- Parameters:
paramSpec
- the parameter specification.- Throws:
InvalidParameterSpecException
- if the given parameter specification is inappropriate for the initialization of this parameter object, or if this parameter object has already been initialized.
-
init
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, or if this parameter object has already been initialized.
-
init
Imports the parameters fromparams
and decodes them according to the specified decoding scheme. Ifformat
isnull
, 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 scheme.- Throws:
IOException
- on decoding errors, or if this parameter object has already been initialized.
-
getParameterSpec
public final <T extends AlgorithmParameterSpec> T getParameterSpec(Class<T> paramSpec) throws InvalidParameterSpecException Returns a (transparent) specification of this parameter object.paramSpec
identifies the specification class in which the parameters should be returned. It could, for example, beDSAParameterSpec.class
, to indicate that the parameters should be returned in an instance of theDSAParameterSpec
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, or if this parameter object has not been initialized.
-
getEncoded
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, or if this parameter object has not been initialized.
-
getEncoded
Returns the parameters encoded in the specified scheme. Ifformat
isnull
, 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, or if this parameter object has not been initialized.
-
toString
-