/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package java.security;
import java.security.spec.AlgorithmParameterSpec;
import org.apache.harmony.security.fortress.Engine;
/**
* {@code AlgorithmParameterGenerator} is an engine class which is capable of
* generating parameters for the algorithm it was initialized with.
*/
public class AlgorithmParameterGenerator {
// Store spi service name
private static final String SERVICE = "AlgorithmParameterGenerator";
// Used to access common engine functionality
private static final Engine ENGINE = new Engine(SERVICE);
// Store SecureRandom
private static final SecureRandom RANDOM = new SecureRandom();
// Store used provider
private final Provider provider;
// Store used AlgorithmParameterGeneratorSpi implementation
private final AlgorithmParameterGeneratorSpi spiImpl;
//Store used algorithm
private final String algorithm;
/**
* Constructs a new instance of {@code AlgorithmParameterGenerator} with the
* given arguments.
*
* @param paramGenSpi
* a concrete implementation, this engine instance delegates to.
* @param provider
* the provider.
* @param algorithm
* the name of the algorithm.
*/
protected AlgorithmParameterGenerator(
AlgorithmParameterGeneratorSpi paramGenSpi, Provider provider,
String algorithm) {
this.provider = provider;
this.algorithm = algorithm;
this.spiImpl = paramGenSpi;
}
/**
* Returns the name of the algorithm.
*
* @return the name of the algorithm.
*/
public final String getAlgorithm() {
return algorithm;
}
/**
* Returns a new instance of {@code AlgorithmParameterGenerator} for the
* specified algorithm.
*
* @param algorithm
* the name of the algorithm to use.
* @return a new instance of {@code AlgorithmParameterGenerator} for the
* specified algorithm.
* @throws NoSuchAlgorithmException
* if the specified algorithm is not available.
* @throws NullPointerException
* if {@code algorithm} is {@code null}.
*/
public static AlgorithmParameterGenerator getInstance(String algorithm)
throws NoSuchAlgorithmException {
if (algorithm == null) {
throw new NullPointerException();
}
Engine.SpiAndProvider sap = ENGINE.getInstance(algorithm, null);
return new AlgorithmParameterGenerator((AlgorithmParameterGeneratorSpi) sap.spi,
sap.provider, algorithm);
}
/**
* Returns a new instance of {@code AlgorithmParameterGenerator} from the
* specified provider for the specified algorithm.
*
* @param algorithm
* the name of the algorithm to use.
* @param provider
* name of the provider of the {@code
* AlgorithmParameterGenerator}.
* @return a new instance of {@code AlgorithmParameterGenerator} for the
* specified algorithm.
* @throws NoSuchAlgorithmException
* if the specified algorithm is not available.
* @throws NoSuchProviderException
* if the specified provider is not available.
* @throws IllegalArgumentException if {@code provider == null || provider.isEmpty()}
* @throws NullPointerException
* if {@code algorithm} is {@code null}.
*/
public static AlgorithmParameterGenerator getInstance(String algorithm,
String provider) throws NoSuchAlgorithmException,
NoSuchProviderException {
if (provider == null || provider.isEmpty()) {
throw new IllegalArgumentException();
}
Provider impProvider = Security.getProvider(provider);
if (impProvider == null) {
throw new NoSuchProviderException(provider);
}
return getInstance(algorithm, impProvider);
}
/**
* Returns a new instance of {@code AlgorithmParameterGenerator} from the
* specified provider for the specified algorithm.
*
* @param algorithm
* the name of the algorithm to use.
* @param provider
* the provider of the {@code AlgorithmParameterGenerator}.
* @return a new instance of {@code AlgorithmParameterGenerator} for the
* specified algorithm.
* @throws NoSuchAlgorithmException
* if the specified algorithm is not available.
* @throws NullPointerException
* if {@code algorithm} is {@code null}.
* @throws IllegalArgumentException if {@code provider == null}
*/
public static AlgorithmParameterGenerator getInstance(String algorithm,
Provider provider) throws NoSuchAlgorithmException {
if (provider == null) {
throw new IllegalArgumentException();
}
if (algorithm == null) {
throw new NullPointerException();
}
Object spi = ENGINE.getInstance(algorithm, provider, null);
return new AlgorithmParameterGenerator((AlgorithmParameterGeneratorSpi) spi, provider,
algorithm);
}
/**
* Returns the provider associated with this {@code
* AlgorithmParameterGenerator}.
*
* @return the provider associated with this {@code
* AlgorithmParameterGenerator}.
*/
public final Provider getProvider() {
return provider;
}
/**
* Initializes this {@code AlgorithmParameterGenerator} with the given size.
* The default parameter set and a default {@code SecureRandom} instance
* will be used.
*
* @param size
* the size (in number of bits).
*/
public final void init(int size) {
spiImpl.engineInit(size, RANDOM);
}
/**
* Initializes this {@code AlgorithmParameterGenerator} with the given size
* and the given {@code SecureRandom}. The default parameter set will be
* used.
*
* @param size
* the size (in number of bits).
* @param random
* the source of randomness.
*/
public final void init(int size, SecureRandom random) {
spiImpl.engineInit(size, random);
}
/**
* Initializes this {@code AlgorithmParameterGenerator} with the given {@code
* AlgorithmParameterSpec}. A default {@code SecureRandom} instance will be
* used.
*
* @param genParamSpec
* the parameters to use.
* @throws InvalidAlgorithmParameterException
* if the specified parameters are not supported.
*/
public final void init(AlgorithmParameterSpec genParamSpec)
throws InvalidAlgorithmParameterException {
spiImpl.engineInit(genParamSpec, RANDOM);
}
/**
* Initializes this {@code AlgorithmParameterGenerator} with the given
* {@code AlgorithmParameterSpec} and the given {@code SecureRandom}.
*
* @param genParamSpec
* the parameters to use.
* @param random
* the source of randomness.
* @throws InvalidAlgorithmParameterException
* if the specified parameters are not supported.
*/
public final void init(AlgorithmParameterSpec genParamSpec,
SecureRandom random) throws InvalidAlgorithmParameterException {
spiImpl.engineInit(genParamSpec, random);
}
/**
* Computes and returns {@code AlgorithmParameters} for this generator's
* algorithm.
*
* @return {@code AlgorithmParameters} for this generator's algorithm.
*/
public final AlgorithmParameters generateParameters() {
return spiImpl.engineGenerateParameters();
}
}