java.security
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).
There are two ways to request such an implementation: by specifying
either just an algorithm name, or both an algorithm name and a package
provider.
- If just an algorithm name is specified, the system will determine if
there is an AlgorithmParameters implementation for the algorithm requested
available in the environment, and if there is more than one, if there is
a preferred one.
- If both an algorithm name and a package provider are specified, the
system will determine if there is an implementation in the package
requested, and throw an exception if there is not.
Once an
AlgorithmParameters
object is returned, 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()
.
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.
|
static AlgorithmParameters | getInstance(String algorithm) - Generates a parameter object for the specified algorithm.
If the default provider package provides an implementation of the
requested algorithm, an instance of
AlgorithmParameters
containing that implementation is returned.
|
static AlgorithmParameters | getInstance(String algorithm, String provider) - Generates a parameter object for the specified algorithm, as supplied
by the specified provider, if such an algorithm is available from the
provider.
The returned parameter object must be initialized via a call to
init() , using an appropriate parameter specification or
parameter encoding.
|
static AlgorithmParameters | getInstance(String algorithm, Provider provider) - Generates an
AlgorithmParameterGenerator object for the
requested algorithm, as supplied from the specified provider, if such a
parameter generator is available from the provider.
|
AlgorithmParameterSpec | getParameterSpec(Class paramSpec) - Returns a (transparent) specification of this parameter object.
|
Provider | getProvider() - Returns the provider of this parameter object.
|
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.
|
void | init(AlgorithmParameterSpec paramSpec) - Initializes this parameter object using the parameters specified in
paramSpec .
|
String | toString() - Returns a formatted string describing the parameters.
|
clone , equals , finalize , getClass , hashCode , notify , notifyAll , toString , wait , wait , wait |
getAlgorithm
public final String getAlgorithm()
Returns the name of the algorithm associated with this parameter object.
getEncoded
public final byte[] getEncoded()
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.
- the parameters encoded using their primary encoding format.
IOException
- on encoding errors, or if this parameter object has not
been initialized.
getEncoded
public final byte[] getEncoded(String format)
throws IOException
Returns the parameters encoded in the specified scheme. 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.
format
- the name of the encoding format.
- the parameters encoded using the specified encoding scheme.
IOException
- on encoding errors, or if this parameter object has
not been initialized.
getInstance
public static AlgorithmParameters getInstance(String algorithm)
throws NoSuchAlgorithmException
Generates a parameter object for the specified algorithm.
If the default provider package provides an implementation of the
requested algorithm, an instance of
AlgorithmParameters
containing that implementation is returned. If the algorithm is not
available in the default package, other packages are searched.
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.
- the new parameter object.
getInstance
public static AlgorithmParameters getInstance(String algorithm,
String provider)
throws NoSuchAlgorithmException,
NoSuchProviderException
Generates a parameter object for the specified algorithm, as supplied
by the specified provider, if such an algorithm is available from the
provider.
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.provider
- the name of the provider.
- the new parameter object.
getInstance
public static AlgorithmParameters getInstance(String algorithm,
Provider provider)
throws NoSuchAlgorithmException
Generates an AlgorithmParameterGenerator
object for the
requested algorithm, as supplied from the specified provider, if such a
parameter generator is available from the provider. Note: the
provider
doesn't have to be registered.
algorithm
- the string name of the algorithm.provider
- the provider.
- the new
AlgorithmParameterGenerator
object.
getParameterSpec
public final AlgorithmParameterSpec getParameterSpec(Class 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, 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.
- the parameter specification.
InvalidParameterSpecException
- if the requested parameter
specification is inappropriate for this parameter object, or if this
parameter object has not been initialized.
getProvider
public final Provider getProvider()
Returns the provider of this parameter object.
- the provider of this parameter object.
init
public final void init(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.
params
- the encoded parameters.
IOException
- on decoding errors, or if this parameter object has
already been initialized.
init
public final void init(byte[] params,
String format)
throws IOException
Imports the parameters from 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.
toString
public final String toString()
Returns a formatted string describing the parameters.
- toString in interface Object
- a formatted string describing the parameters, or
null
if this parameter object has not been initialized.
AlgorithmParameters.java --- Algorithm Parameters Implementation Class
Copyright (C) 1999, 2003, 2004 Free Software Foundation, Inc.
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