001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019
020package org.apache.shiro.crypto.hash;
021
022import java.util.Optional;
023import java.util.ServiceLoader;
024import java.util.stream.StreamSupport;
025
026import static java.util.Objects.requireNonNull;
027
028/**
029 * Hashes used by the Shiro2CryptFormat class.
030 *
031 * <p>Instead of maintaining them as an {@code Enum}, ServiceLoaders would provide a pluggable alternative.</p>
032 *
033 * @since 2.0
034 */
035public final class HashProvider {
036
037    private HashProvider() {
038        // utility class
039    }
040
041    /**
042     * Find a KDF implementation by searching the algorithms.
043     *
044     * @param algorithmName the algorithmName to match. This is case-sensitive.
045     * @return an instance of {@link HashProvider} if found, otherwise {@link Optional#empty()}.
046     * @throws NullPointerException if the given parameter algorithmName is {@code null}.
047     */
048    public static Optional<HashSpi> getByAlgorithmName(String algorithmName) {
049        requireNonNull(algorithmName, "algorithmName in HashProvider.getByAlgorithmName");
050        ServiceLoader<HashSpi> hashSpis = load();
051
052        return StreamSupport.stream(hashSpis.spliterator(), false)
053                .filter(hashSpi -> hashSpi.getImplementedAlgorithms().contains(algorithmName))
054                .findAny();
055    }
056
057    @SuppressWarnings("unchecked")
058    private static ServiceLoader<HashSpi> load() {
059        return ServiceLoader.load(HashSpi.class);
060    }
061
062}