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 */
019package org.eclipse.aether.util.repository;
020
021import org.eclipse.aether.repository.Authentication;
022import org.eclipse.aether.repository.AuthenticationSelector;
023import org.eclipse.aether.repository.RemoteRepository;
024
025import static java.util.Objects.requireNonNull;
026
027/**
028 * An authentication selector that delegates to another selector but only if a repository has no authentication data
029 * yet. If authentication has already been assigned to a repository, that is selected.
030 */
031public final class ConservativeAuthenticationSelector implements AuthenticationSelector {
032
033    private final AuthenticationSelector selector;
034
035    /**
036     * Creates a new selector that delegates to the specified selector.
037     *
038     * @param selector The selector to delegate to in case a repository has no authentication yet, must not be
039     *            {@code null}.
040     */
041    public ConservativeAuthenticationSelector(AuthenticationSelector selector) {
042        this.selector = requireNonNull(selector, "authentication selector cannot be null");
043    }
044
045    public Authentication getAuthentication(RemoteRepository repository) {
046        requireNonNull(repository, "repository cannot be null");
047        Authentication auth = repository.getAuthentication();
048        if (auth != null) {
049            return auth;
050        }
051        return selector.getAuthentication(repository);
052    }
053}