001package org.eclipse.aether.util.repository;
002
003/*
004 * Licensed to the Apache Software Foundation (ASF) under one
005 * or more contributor license agreements.  See the NOTICE file
006 * distributed with this work for additional information
007 * regarding copyright ownership.  The ASF licenses this file
008 * to you under the Apache License, Version 2.0 (the
009 * "License"); you may not use this file except in compliance
010 * with the License.  You may obtain a copy of the License at
011 * 
012 *  http://www.apache.org/licenses/LICENSE-2.0
013 * 
014 * Unless required by applicable law or agreed to in writing,
015 * software distributed under the License is distributed on an
016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017 * KIND, either express or implied.  See the License for the
018 * specific language governing permissions and limitations
019 * under the License.
020 */
021
022import org.eclipse.aether.repository.Authentication;
023import org.eclipse.aether.repository.AuthenticationSelector;
024import org.eclipse.aether.repository.RemoteRepository;
025
026/**
027 * An authentication selector that delegates to another selector but only if a repository has no authentication data
028 * yet. If authentication has already been assigned to a repository, that is selected.
029 */
030public final class ConservativeAuthenticationSelector
031    implements AuthenticationSelector
032{
033
034    private final AuthenticationSelector selector;
035
036    /**
037     * Creates a new selector that delegates to the specified selector.
038     * 
039     * @param selector The selector to delegate to in case a repository has no authentication yet, must not be
040     *            {@code null}.
041     */
042    public ConservativeAuthenticationSelector( AuthenticationSelector selector )
043    {
044        if ( selector == null )
045        {
046            throw new IllegalArgumentException( "no authentication selector specified" );
047        }
048        this.selector = selector;
049    }
050
051    public Authentication getAuthentication( RemoteRepository repository )
052    {
053        Authentication auth = repository.getAuthentication();
054        if ( auth != null )
055        {
056            return auth;
057        }
058        return selector.getAuthentication( repository );
059    }
060
061}