JavaTM 2 Platform
Std. Ed. v1.3.1

java.security
Class AlgorithmParameters

java.lang.Object
  |
  +--java.security.AlgorithmParameters

public class AlgorithmParameters
extends Object

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.

Since:
1.2
See Also:
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

AlgorithmParameters

protected AlgorithmParameters(AlgorithmParametersSpi paramSpi,
                              Provider provider,
                              String algorithm)
Creates an AlgorithmParameters object.
Parameters:
paramSpi - the delegate
provider - the provider
algorithm - the algorithm
Method Detail

getAlgorithm

public final String getAlgorithm()
Returns the name of the algorithm associated with this parameter object.
Returns:
the algorithm name.

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.

Parameters:
algorithm - the name of the algorithm requested.
Returns:
the new parameter object.
Throws:
NoSuchAlgorithmException - if the algorithm is not available in the environment.

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.

Parameters:
algorithm - the name of the algorithm requested.
provider - the name of the provider.
Returns:
the new parameter object.
Throws:
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.
See Also:
Provider

getProvider

public final Provider getProvider()
Returns the provider of this parameter object.
Returns:
the provider of this parameter object

init

public final void init(AlgorithmParameterSpec paramSpec)
                throws InvalidParameterSpecException
Initializes this parameter 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, or if this parameter object has already been initialized.

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.
Parameters:
params - the encoded parameters.
Throws:
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.
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 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.
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

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.
Returns:
the parameters encoded using their primary encoding format.
Throws:
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.
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

public final String toString()
Returns a formatted string describing the parameters.
Overrides:
toString in class Object
Returns:
a formatted string describing the parameters, or null if this parameter object has not been initialized.

JavaTM 2 Platform
Std. Ed. v1.3.1

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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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