bmarwell commented on a change in pull request #273: URL: https://github.com/apache/shiro/pull/273#discussion_r554373598
########## File path: crypto/hash/src/main/java/org/apache/shiro/crypto/hash/HashProvider.java ########## @@ -0,0 +1,60 @@ +/* + * 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 org.apache.shiro.crypto.hash; + +import java.util.Optional; +import java.util.ServiceLoader; +import java.util.stream.StreamSupport; + +import static java.util.Objects.requireNonNull; + +/** + * Hashes used by the Shiro2CryptFormat class. + * + * <p>Instead of maintaining them as an {@code Enum}, ServiceLoaders would provide a pluggable alternative.</p> + */ +public final class HashProvider { + + private HashProvider() { + // utility class + } + + /** + * Find a KDF implementation by searching the algorithms. + * + * @param algorithmName the algorithmName to match. This is case-sensitive. + * @return an instance of {@link HashProvider} if found, otherwise {@link Optional#empty()}. + * @throws NullPointerException if the given parameter algorithmName is {@code null}. + */ + public static Optional<HashSpi<? extends Hash>> getByAlgorithmName(String algorithmName) { + requireNonNull(algorithmName, "algorithmName in HashProvider.getByAlgorithmName"); + ServiceLoader<HashSpi<? extends Hash>> hashSpis = load(); + + return StreamSupport.stream(hashSpis.spliterator(), false) + .filter(hashSpi -> hashSpi.getImplementedAlgorithms().contains(algorithmName)) + .findAny(); + } + + @SuppressWarnings("unchecked") + private static ServiceLoader<HashSpi<? extends Hash>> load() { + return (ServiceLoader<HashSpi<? extends Hash>>) (Object) ServiceLoader.load(HashSpi.class); Review comment: What bugs me most is the ugly casting to object and back. But with what I saw from your `jjwt` example, adding a parameter might help with that! ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
