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JavaTM 2 Platform Std. Ed. v1.3.1 |
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java.lang.Object | +--java.security.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.
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
.
AlgorithmParameterSpec
,
DSAParameterSpec
,
KeyPairGenerator
Constructor Summary | |
protected |
AlgorithmParameters(AlgorithmParametersSpi paramSpi,
Provider provider,
String algorithm)
Creates an AlgorithmParameters object. |
Method Summary | |
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. |
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. |
AlgorithmParameterSpec |
getParameterSpec(Class paramSpec)
Returns a (transparent) specification of this parameter object. |
Provider |
getProvider()
Returns the provider of this parameter object. |
void |
init(AlgorithmParameterSpec paramSpec)
Initializes this parameter object using the parameters specified in paramSpec . |
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. |
String |
toString()
Returns a formatted string describing the parameters. |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Constructor Detail |
protected AlgorithmParameters(AlgorithmParametersSpi paramSpi, Provider provider, String algorithm)
paramSpi
- the delegateprovider
- the provideralgorithm
- the algorithmMethod Detail |
public final String getAlgorithm()
public static AlgorithmParameters getInstance(String algorithm) throws NoSuchAlgorithmException
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.NoSuchAlgorithmException
- if the algorithm is
not available in the environment.public static AlgorithmParameters getInstance(String algorithm, String provider) throws NoSuchAlgorithmException, NoSuchProviderException
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.NoSuchAlgorithmException
- if the algorithm is
not available in the package supplied by the requested
provider.NoSuchProviderException
- if the provider is not
available in the environment.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 AlgorithmParameterSpec getParameterSpec(Class 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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JavaTM 2 Platform Std. Ed. v1.3.1 |
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