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.synccontext.named;
020
021import java.util.Collection;
022
023import org.eclipse.aether.RepositorySystemSession;
024import org.eclipse.aether.artifact.Artifact;
025import org.eclipse.aether.metadata.Metadata;
026
027/**
028 * Component mapping lock names to passed in artifacts and metadata as required.
029 */
030public interface NameMapper {
031    /**
032     * Returns {@code true} if lock names returned by this lock name mapper are file system friendly, can be used
033     * as file names and paths.
034     *
035     * @since 1.9.0
036     */
037    boolean isFileSystemFriendly();
038
039    /**
040     * Creates (opaque) names for passed in artifacts and metadata. Returned collection has max size of sum of the
041     * passed in artifacts and metadata collections, or less. If an empty collection is returned, there will be no
042     * locking happening. Never returns {@code null}. The resulting collection MUST BE "stable" (always sorted by
043     * same criteria) to avoid deadlocks by acquiring locks in same order, essentially disregarding the order of
044     * the input collections.
045     * <p>
046     * There is no requirement of any kind of "parity" between input element count (sum of two collections, that is)
047     * and output collection size, just the returned upper size limit is defined (sum of the passed in two collections
048     * size). If returned collection is empty, no locking will happen, if single element, one lock will be used, if two
049     * then two named locks will be used etc.
050     * <p>
051     * Note: name mapper must not use same string for artifacts and metadata, so even the simplest possible
052     * implementation like {@link StaticNameMapper} uses two different static strings.
053     */
054    Collection<String> nameLocks(
055            RepositorySystemSession session,
056            Collection<? extends Artifact> artifacts,
057            Collection<? extends Metadata> metadatas);
058}