java.security

Class AlgorithmParameterGenerator


public class AlgorithmParameterGenerator
extends Object

The AlgorithmParameterGenerator class is used to generate a set of parameters to be used with a certain algorithm. Parameter generators are constructed using the getInstance() factory methods (static methods that return instances of a given class).

The object that will generate the parameters can be initialized in two different ways: in an algorithm-independent manner, or in an algorithm-specific manner:

In case the client does not explicitly initialize the AlgorithmParameterGenerator (via a call to an init() method), each provider must supply (and document) a default initialization. For example, the GNU provider uses a default modulus prime size of 1024 bits for the generation of DSA parameters.

Since:
1.2
See Also:
AlgorithmParameters, AlgorithmParameterSpec

Constructor Summary

AlgorithmParameterGenerator(AlgorithmParameterGeneratorSpi paramGenSpi, Provider provider, String algorithm)
Creates an AlgorithmParameterGenerator object.

Method Summary

AlgorithmParameters
generateParameters()
Generates the parameters.
String
getAlgorithm()
Returns the standard name of the algorithm this parameter generator is associated with.
static AlgorithmParameterGenerator
getInstance(String algorithm)
Generates an AlgorithmParameterGenerator object that implements the specified digest algorithm.
static AlgorithmParameterGenerator
getInstance(String algorithm, String 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.
static AlgorithmParameterGenerator
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.
Provider
getProvider()
Returns the provider of this algorithm parameter generator object.
void
init(int size)
Initializes this parameter generator for a certain size.
void
init(int size, SecureRandom random)
Initializes this parameter generator for a certain size and source of randomness.
void
init(AlgorithmParameterSpec genParamSpec)
Initializes this parameter generator with a set of algorithm-specific parameter generation values.
void
init(AlgorithmParameterSpec genParamSpec, SecureRandom random)
Initializes this parameter generator with a set of algorithm-specific parameter generation values.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

AlgorithmParameterGenerator

protected AlgorithmParameterGenerator(AlgorithmParameterGeneratorSpi paramGenSpi,
                                      Provider provider,
                                      String algorithm)
Creates an AlgorithmParameterGenerator object.
Parameters:
paramGenSpi - the delegate.
provider - the provider.
algorithm - the algorithm.

Method Details

generateParameters

public final AlgorithmParameters generateParameters()
Generates the parameters.
Returns:
the new AlgorithmParameters object.

getAlgorithm

public final String getAlgorithm()
Returns the standard name of the algorithm this parameter generator is associated with.
Returns:
the string name of the algorithm.

getInstance

public static AlgorithmParameterGenerator getInstance(String algorithm)
            throws NoSuchAlgorithmException
Generates an AlgorithmParameterGenerator object that implements the specified digest algorithm. If the default provider package provides an implementation of the requested digest algorithm, an instance of AlgorithmParameterGenerator containing that implementation is returned. If the algorithm is not available in the default package, other packages are searched.
Parameters:
algorithm - the string name of the algorithm this parameter generator is associated with.
Returns:
the new AlgorithmParameterGenerator object.
Throws:
NoSuchAlgorithmException - if the algorithm is not available in the environment.

getInstance

public static AlgorithmParameterGenerator getInstance(String algorithm,
                                                      String provider)
            throws NoSuchAlgorithmException,
                   NoSuchProviderException
Generates an AlgorithmParameterGenerator object for the requested algorithm, as supplied from the specified provider, if such a parameter generator is available from the provider.
Parameters:
algorithm - the string name of the algorithm.
provider - the string name of the provider.
Returns:
the new AlgorithmParameterGenerator object.
Throws:
NoSuchAlgorithmException - if the algorithm is not available from the provider.
NoSuchProviderException - if the provider is not available in the environment.
IllegalArgumentException - if the provider name is null or empty.
See Also:
Provider

getInstance

public static AlgorithmParameterGenerator 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.
Parameters:
algorithm - the string name of the algorithm.
provider - the provider.
Returns:
the new AlgorithmParameterGenerator object.
Throws:
NoSuchAlgorithmException - if the algorithm is not available from the provider.
IllegalArgumentException - if the provider is null.
Since:
1.4
See Also:
Provider

getProvider

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

init

public final void init(int size)
Initializes this parameter generator for a certain size. To create the parameters, the SecureRandom implementation of the highest-priority installed provider is used as the source of randomness. (If none of the installed providers supply an implementation of SecureRandom, a system-provided source of randomness is used.)
Parameters:
size - the size (number of bits).

init

public final void init(int size,
                       SecureRandom random)
Initializes this parameter generator for a certain size and source of randomness.
Parameters:
size - the size (number of bits).
random - the source of randomness.

init

public final void init(AlgorithmParameterSpec genParamSpec)
            throws InvalidAlgorithmParameterException
Initializes this parameter generator with a set of algorithm-specific parameter generation values. To generate the parameters, the SecureRandom implementation of the highest-priority installed provider is used as the source of randomness. (If none of the installed providers supply an implementation of SecureRandom, a system-provided source of randomness is used.)
Parameters:
genParamSpec - the set of algorithm-specific parameter generation values.
Throws:
InvalidAlgorithmParameterException - if the given parameter generation values are inappropriate for this parameter generator.

init

public final void init(AlgorithmParameterSpec genParamSpec,
                       SecureRandom random)
            throws InvalidAlgorithmParameterException
Initializes this parameter generator with a set of algorithm-specific parameter generation values.
Parameters:
genParamSpec - the set of algorithm-specific parameter generation values.
random - the source of randomness.
Throws:
InvalidAlgorithmParameterException - if the given parameter generation values are inappropriate for this parameter generator.

AlgorithmParameterGenerator.java --- Algorithm Parameter Generator Copyright (C) 1999, 2003, 2004 Free Software Foundation, Inc. This file is part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU Classpath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; see the file COPYING. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.