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/* AlgorithmParameterGenerator.java --- Algorithm Parameter Generator
Copyright (c) 1999 by Free Software Foundation, Inc.
Written by Mark Benvenuto <ivymccough@worldnet.att.net>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Library General Public License as published
by the Free Software Foundation, version 2. (see COPYING.LIB)
This program 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 this program; if not, write to the Free Software Foundation
Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307 USA. */
package java.security;
import java.security.spec.AlgorithmParameterSpec;
/**
AlgorithmParameterGenerator is used to generate
algorithm parameters for specified algorithms.
This class is used to generate the algorithm parameters
for a specific algorithm.
@since JDK 1.2
@author Mark Benvenuto
*/
public class AlgorithmParameterGenerator
{
private AlgorithmParameterGeneratorSpi paramGenSpi;
private Provider provider;
private String algorithm;
/**
Creates an instance of AlgorithmParameters
@param paramSpi A parameters engine to use
@param provider A provider to use
@param algorithm The algorithm
*/
protected AlgorithmParameterGenerator(AlgorithmParameterGeneratorSpi paramGenSpi, Provider provider, String algorithm)
{
this.paramGenSpi = paramGenSpi;
this.provider = provider;
this.algorithm = algorithm;
}
/**
Returns the name of the algorithm used
@return A string with the name of the algorithm
*/
public final String getAlgorithm()
{
return algorithm;
}
/**
Gets an instance of the AlgorithmParameterGenerator class
which generates algorithm parameters for the specified algorithm.
If the algorithm is not found then, it throws NoSuchAlgorithmException.
@param algorithm the name of algorithm to choose
@return a AlgorithmParameterGenerator repesenting the desired algorithm
@throws NoSuchAlgorithmException if the algorithm is not implemented by providers
*/
public static AlgorithmParameterGenerator getInstance(String algorithm)
throws NoSuchAlgorithmException
{
Provider[] p = Security.getProviders ();
for (int i = 0; i < p.length; i++)
{
String classname = p[i].getProperty ("AlgorithmParameterGenerator." + algorithm);
if (classname != null)
return getInstance (classname, algorithm, p[i]);
}
throw new NoSuchAlgorithmException (algorithm);
}
/**
Gets an instance of the AlgorithmParameterGenerator class
which generates algorithm parameters for the specified algorithm.
If the algorithm is not found then, it throws NoSuchAlgorithmException.
@param algorithm the name of algorithm to choose
@param provider the name of the provider to find the algorithm in
@return a AlgorithmParameterGenerator repesenting the desired algorithm
@throws NoSuchAlgorithmException if the algorithm is not implemented by the provider
@throws NoSuchProviderException if the provider is not found
*/
public static AlgorithmParameterGenerator getInstance(String algorithm, String provider)
throws NoSuchAlgorithmException, NoSuchProviderException
{
Provider p = Security.getProvider(provider);
if( p == null)
throw new NoSuchProviderException();
return getInstance (p.getProperty ("AlgorithmParameterGenerator." + algorithm),
algorithm, p);
}
private static AlgorithmParameterGenerator getInstance (String classname,
String algorithm,
Provider provider)
throws NoSuchAlgorithmException
{
try {
return new AlgorithmParameterGenerator( (AlgorithmParameterGeneratorSpi )Class.forName( classname ).newInstance(), provider, algorithm );
} catch( ClassNotFoundException cnfe) {
throw new NoSuchAlgorithmException("Class not found");
} catch( InstantiationException ie) {
throw new NoSuchAlgorithmException("Class instantiation failed");
} catch( IllegalAccessException iae) {
throw new NoSuchAlgorithmException("Illegal Access");
}
}
/**
Gets the provider that the class is from.
@return the provider of this class
*/
public final Provider getProvider()
{
return provider;
}
/**
Initializes the Algorithm Parameter Generator with the specified
size. (Since no source of randomness is supplied, a default
one is supplied).
@param size size (in bits) to use
*/
public final void init(int size)
{
init( size, new SecureRandom() );
}
/**
Initializes the Algorithm Parameter Generator with the specified
size and source of randomness.
@param size size (in bits) to use
@param random source of randomness to use
*/
public final void init(int size, SecureRandom random)
{
paramGenSpi.engineInit( size, random );
}
/**
Initializes the Algorithm Parameter Generator with the specified
AlgorithmParameterSpec. (Since no source of randomness is supplied,
a default one is supplied).
@param genParamSpec the AlgorithmParameterSpec class to use
*/
public final void init(AlgorithmParameterSpec genParamSpec) throws InvalidAlgorithmParameterException
{
init( genParamSpec, new SecureRandom() );
}
/**
Initializes the Algorithm Parameter Generator with the specified
AlgorithmParameterSpec and source of randomness.
@param genParamSpec the AlgorithmParameterSpec class to use
@param random source of randomness to use
*/
public final void init(AlgorithmParameterSpec genParamSpec, SecureRandom random) throws InvalidAlgorithmParameterException
{
paramGenSpi.engineInit( genParamSpec, random );
}
/**
Generate a new set of AlgorithmParameters.
@returns a new set of algorithm parameters
*/
public final AlgorithmParameters generateParameters()
{
return paramGenSpi.engineGenerateParameters();
}
}
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