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Java™ Platform Standard Ed. 6 |
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java.lang.Object java.security.AlgorithmParameters
public class AlgorithmParameters
This class is used as an opaque representation of cryptographic parameters.
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
.
AlgorithmParameterSpec
,
DSAParameterSpec
,
KeyPairGenerator
Constructor Summary | |
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protected |
AlgorithmParameters(AlgorithmParametersSpi paramSpi,
Provider provider,
String algorithm)
Creates an AlgorithmParameters object. |
Method Summary | ||
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String |
getAlgorithm()
Returns the name of the algorithm associated with this parameter object. |
|
byte[] |
getEncoded()
Returns the parameters in their primary encoding format. |
|
byte[] |
getEncoded(String format)
Returns the parameters encoded in the specified scheme. |
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static AlgorithmParameters |
getInstance(String algorithm)
Returns a parameter object for the specified algorithm. |
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static AlgorithmParameters |
getInstance(String algorithm,
Provider provider)
Returns a parameter object for the specified algorithm. |
|
static AlgorithmParameters |
getInstance(String algorithm,
String provider)
Returns a parameter object for the specified algorithm. |
|
|
getParameterSpec(Class<T> paramSpec)
Returns a (transparent) specification of this parameter object. |
|
Provider |
getProvider()
Returns the provider of this parameter object. |
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void |
init(AlgorithmParameterSpec paramSpec)
Initializes this parameter object using the parameters specified in paramSpec . |
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void |
init(byte[] params)
Imports the specified parameters and decodes them according to the primary decoding format for parameters. |
|
void |
init(byte[] params,
String format)
Imports the parameters from params and decodes them
according to the specified decoding scheme. |
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String |
toString()
Returns a formatted string describing the parameters. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Constructor Detail |
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protected AlgorithmParameters(AlgorithmParametersSpi paramSpi, Provider provider, String algorithm)
paramSpi
- the delegateprovider
- the provideralgorithm
- the algorithmMethod Detail |
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public final String getAlgorithm()
public static AlgorithmParameters getInstance(String algorithm) throws NoSuchAlgorithmException
This method traverses the list of registered security Providers, starting with the most preferred Provider. A new AlgorithmParameters object encapsulating the AlgorithmParametersSpi 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.
algorithm
- the name of the algorithm requested.
See Appendix A in the
Java Cryptography Architecture API Specification & Reference
for information about standard algorithm names.
NoSuchAlgorithmException
- if no Provider supports an
AlgorithmParametersSpi implementation for the
specified algorithm.Provider
public static AlgorithmParameters getInstance(String algorithm, String provider) throws NoSuchAlgorithmException, NoSuchProviderException
A new AlgorithmParameters object encapsulating the AlgorithmParametersSpi 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.
algorithm
- the name of the algorithm requested.
See Appendix A in the
Java Cryptography Architecture API Specification & Reference
for information about standard algorithm names.provider
- the name of the provider.
NoSuchAlgorithmException
- if an AlgorithmParametersSpi
implementation for the specified algorithm is not
available from the specified provider.
NoSuchProviderException
- if the specified provider is not
registered in the security provider list.
IllegalArgumentException
- if the provider name is null
or empty.Provider
public static AlgorithmParameters getInstance(String algorithm, Provider provider) throws NoSuchAlgorithmException
A new AlgorithmParameters object encapsulating the AlgorithmParametersSpi implementation from the specified Provider object is returned. Note that the specified Provider object 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.
algorithm
- the name of the algorithm requested.
See Appendix A in the
Java Cryptography Architecture API Specification & Reference
for information about standard algorithm names.provider
- the name of the provider.
NoSuchAlgorithmException
- if an AlgorithmParameterGeneratorSpi
implementation for the specified algorithm is not available
from the specified Provider object.
IllegalArgumentException
- if the provider is null.Provider
public final Provider getProvider()
public final void init(AlgorithmParameterSpec paramSpec) throws InvalidParameterSpecException
paramSpec
.
paramSpec
- the parameter specification.
InvalidParameterSpecException
- if the given parameter
specification is inappropriate for the initialization of this parameter
object, or if this parameter object has already been initialized.public final void init(byte[] params) throws IOException
params
- the encoded parameters.
IOException
- on decoding errors, or if this parameter object
has already been initialized.public final void init(byte[] params, String format) throws IOException
params
and decodes them
according to the specified decoding scheme.
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.
params
- the encoded parameters.format
- the name of the decoding scheme.
IOException
- on decoding errors, or if this parameter object
has already been initialized.public final <T extends AlgorithmParameterSpec> T getParameterSpec(Class<T> paramSpec) throws InvalidParameterSpecException
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.
paramSpec
- the specification class in which
the parameters should be returned.
InvalidParameterSpecException
- if the requested parameter
specification is inappropriate for this parameter object, or if this
parameter object has not been initialized.public final byte[] getEncoded() throws IOException
IOException
- on encoding errors, or if this parameter object
has not been initialized.public final byte[] getEncoded(String format) throws IOException
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.
format
- the name of the encoding format.
IOException
- on encoding errors, or if this parameter object
has not been initialized.public final String toString()
toString
in class Object
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