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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.eclipse.aether.internal.impl.synccontext.named;
20  
21  import java.util.Collection;
22  
23  import org.eclipse.aether.RepositorySystemSession;
24  import org.eclipse.aether.artifact.Artifact;
25  import org.eclipse.aether.metadata.Metadata;
26  import org.eclipse.aether.named.NamedLockKey;
27  
28  /**
29   * Component mapping lock names to passed in artifacts and metadata as required.
30   */
31  public interface NameMapper {
32      /**
33       * Returns {@code true} if lock names returned by this lock name mapper are file system friendly, can be used
34       * as file names and paths.
35       * <p>
36       * <em>Note:</em> The fact that name mapper is "file system friendly" means ONLY that names it produces CAN be
37       * used as file names and paths. Still, it does not mean they will work with ANY file based locking, as for example
38       * {@link org.eclipse.aether.named.providers.FileLockNamedLockFactory} expects names as string encoded
39       * {@link java.net.URI}s. The only name mapper doing it is {@link BasedirNameMapper}.
40       *
41       * @since 1.9.0
42       */
43      boolean isFileSystemFriendly();
44  
45      /**
46       * Creates (opaque) names for passed in artifacts and metadata. Returned collection has max size of sum of the
47       * passed in artifacts and metadata collections, or less. If an empty collection is returned, there will be no
48       * locking happening. Never returns {@code null}. The resulting collection MUST BE "stable" (always sorted by
49       * same criteria) to avoid deadlocks by acquiring locks in same order, essentially disregarding the order of
50       * the input collections.
51       * <p>
52       * There is no requirement of any kind of "parity" between input element count (sum of two collections, that is)
53       * and output collection size, just the returned upper size limit is defined (sum of the passed in two collections
54       * size). If returned collection is empty, no locking will happen, if single element, one lock will be used, if two
55       * then two named locks will be used etc.
56       * <p>
57       * Note: name mapper must not use same string for artifacts and metadata, so even the simplest possible
58       * implementation like {@link StaticNameMapper} uses two different static strings.
59       */
60      Collection<NamedLockKey> nameLocks(
61              RepositorySystemSession session,
62              Collection<? extends Artifact> artifacts,
63              Collection<? extends Metadata> metadatas);
64  }