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.internal.impl.filter;
020
021import javax.inject.Inject;
022import javax.inject.Named;
023import javax.inject.Singleton;
024
025import java.util.Collections;
026import java.util.HashMap;
027import java.util.Map;
028import java.util.stream.Collectors;
029
030import org.eclipse.aether.RepositorySystemSession;
031import org.eclipse.aether.artifact.Artifact;
032import org.eclipse.aether.impl.RemoteRepositoryFilterManager;
033import org.eclipse.aether.metadata.Metadata;
034import org.eclipse.aether.repository.RemoteRepository;
035import org.eclipse.aether.spi.connector.filter.RemoteRepositoryFilter;
036import org.eclipse.aether.spi.connector.filter.RemoteRepositoryFilterSource;
037
038import static java.util.Objects.requireNonNull;
039
040/**
041 * Default implementation of {@link RemoteRepositoryFilterManager}, it always returns a {@link RemoteRepositoryFilter}
042 * instance, even if no filter sources enabled/registered (then "always allow" instance).
043 * <p>
044 * The created {@link RemoteRepositoryFilter} instance is created once per session and cached.
045 *
046 * @since 1.9.0
047 */
048@Singleton
049@Named
050public final class DefaultRemoteRepositoryFilterManager implements RemoteRepositoryFilterManager {
051    private static final String INSTANCE_KEY = DefaultRemoteRepositoryFilterManager.class.getName() + ".instance";
052
053    private final Map<String, RemoteRepositoryFilterSource> sources;
054
055    @Inject
056    public DefaultRemoteRepositoryFilterManager(Map<String, RemoteRepositoryFilterSource> sources) {
057        this.sources = requireNonNull(sources);
058    }
059
060    @Override
061    public RemoteRepositoryFilter getRemoteRepositoryFilter(RepositorySystemSession session) {
062        // use session specific key to distinguish between "derived" sessions
063        String instanceSpecificKey = INSTANCE_KEY + "." + session.hashCode();
064        return (RemoteRepositoryFilter) session.getData().computeIfAbsent(instanceSpecificKey, () -> {
065            HashMap<String, RemoteRepositoryFilter> filters = new HashMap<>();
066            for (Map.Entry<String, RemoteRepositoryFilterSource> entry : sources.entrySet()) {
067                RemoteRepositoryFilter filter = entry.getValue().getRemoteRepositoryFilter(session);
068                if (filter != null) {
069                    filters.put(entry.getKey(), filter);
070                }
071            }
072            if (!filters.isEmpty()) {
073                return new Participants(filters);
074            } else {
075                return null;
076            }
077        });
078    }
079
080    /**
081     * {@link RemoteRepositoryFilter} instance when there are participant filters present. It evaluates into result
082     * using {@link Consensus}.
083     */
084    private static class Participants implements RemoteRepositoryFilter {
085        private final Map<String, RemoteRepositoryFilter> participants;
086
087        private Participants(Map<String, RemoteRepositoryFilter> participants) {
088            this.participants = Collections.unmodifiableMap(participants);
089        }
090
091        @Override
092        public RemoteRepositoryFilter.Result acceptArtifact(RemoteRepository remoteRepository, Artifact artifact) {
093            return new Consensus(
094                    participants.entrySet().stream().collect(Collectors.toMap(Map.Entry::getKey, e -> e.getValue()
095                            .acceptArtifact(remoteRepository, artifact))));
096        }
097
098        @Override
099        public RemoteRepositoryFilter.Result acceptMetadata(RemoteRepository remoteRepository, Metadata metadata) {
100            return new Consensus(
101                    participants.entrySet().stream().collect(Collectors.toMap(Map.Entry::getKey, e -> e.getValue()
102                            .acceptMetadata(remoteRepository, metadata))));
103        }
104    }
105
106    /**
107     * {@link RemoteRepositoryFilter.Result} based on "consensus". All participant have to "accept" to make this
108     * instance "accept".
109     */
110    private static class Consensus implements RemoteRepositoryFilter.Result {
111        private final boolean accepted;
112
113        private final String reasoning;
114
115        Consensus(Map<String, RemoteRepositoryFilter.Result> results) {
116            this.accepted = results.values().stream().allMatch(RemoteRepositoryFilter.Result::isAccepted);
117            this.reasoning = results.values().stream()
118                    .filter(r -> !r.isAccepted())
119                    .map(RemoteRepositoryFilter.Result::reasoning)
120                    .collect(Collectors.joining("; "));
121        }
122
123        @Override
124        public boolean isAccepted() {
125            return accepted;
126        }
127
128        @Override
129        public String reasoning() {
130            return reasoning;
131        }
132    }
133}