/** @throws InvalidKeyException if the specified key cannot be used to initialize any provider. */
private static Engine.SpiAndProvider tryAlgorithm(Key key, Provider provider, String algorithm)
throws InvalidKeyException {
if (provider != null) {
Provider.Service service = provider.getService(SERVICE, algorithm);
if (service == null) {
return null;
}
return tryAlgorithmWithProvider(null, service);
}
ArrayList<Provider.Service> services = ENGINE.getServices(algorithm);
if (services == null || services.isEmpty()) {
return null;
}
boolean keySupported = false;
for (Provider.Service service : services) {
if (key == null || service.supportsParameter(key)) {
keySupported = true;
Engine.SpiAndProvider sap = tryAlgorithmWithProvider(key, service);
if (sap != null) {
return sap;
}
}
}
if (!keySupported) {
throw new InvalidKeyException("No provider supports the provided key");
}
return null;
}
public static final CertificateFactory getInstance(String type) throws CertificateException {
if (type == null) {
throw new NullPointerException("type == null");
}
try {
SpiAndProvider sap = ENGINE.getInstance(type, null);
return new CertificateFactory((CertificateFactorySpi) sap.spi, sap.provider, type);
} catch (Throwable e) {
throw new CertificateException(e);
}
}
public static final CertificateFactory getInstance(String type, Provider provider)
throws CertificateException {
if (provider == null) {
throw new IllegalArgumentException("provider == null");
} else if (type == null) {
throw new NullPointerException("type == null");
} else {
try {
return new CertificateFactory(
(CertificateFactorySpi) ENGINE.getInstance(type, provider, null), provider, type);
} catch (Throwable e) {
throw new CertificateException(e);
}
}
}
/**
* Returns a new instance of {@code MessageDigest} that utilizes the specified algorithm.
*
* @param algorithm the name of the algorithm to use
* @return a new instance of {@code MessageDigest} that utilizes the specified algorithm
* @throws NoSuchAlgorithmException if the specified algorithm is not available
* @throws NullPointerException if {@code algorithm} is {@code null}
*/
public static MessageDigest getInstance(String algorithm) throws NoSuchAlgorithmException {
if (algorithm == null) {
throw new NullPointerException();
}
MessageDigest result;
synchronized (engine) {
engine.getInstance(algorithm, null);
if (engine.spi instanceof MessageDigest) {
result = (MessageDigest) engine.spi;
result.algorithm = algorithm;
result.provider = engine.provider;
return result;
}
return new MessageDigestImpl((MessageDigestSpi) engine.spi, engine.provider, algorithm);
}
}
private static Engine.SpiAndProvider tryAlgorithmWithProvider(Key key, Provider.Service service) {
try {
if (key != null && !service.supportsParameter(key)) {
return null;
}
Engine.SpiAndProvider sap = ENGINE.getInstance(service, null);
if (sap.spi == null || sap.provider == null) {
return null;
}
if (!(sap.spi instanceof SignatureSpi)) {
return null;
}
return sap;
} catch (NoSuchAlgorithmException ignored) {
}
return null;
}
