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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.apache.maven.api.services.model;
20  
21  import java.util.function.Supplier;
22  
23  import org.apache.maven.api.annotations.Experimental;
24  import org.apache.maven.api.annotations.ThreadSafe;
25  import org.apache.maven.api.services.Source;
26  
27  /**
28   * Caches auxiliary data used during model building like already processed raw/effective models. The data in the cache
29   * is meant for exclusive consumption by the model builder and is opaque to the cache implementation. The cache key is
30   * formed by a combination of group id, artifact id, version and tag, or by the pom path on the filesystem and tag.
31   * The tag allows for further classification of the associated data on the sole discretion of the model builder.
32   * The cache is expected to be valid through the lifetime of the session, so the model builder is not allowed to
33   * store data which may change during the session, especially effective models which may be different if the
34   * user properties or activate profiles change between two invocations of the model builder.
35   * The cache implementation is expected to be thread-safe.
36   *
37   * @since 4.0.0
38   */
39  @Experimental
40  @ThreadSafe
41  public interface ModelCache {
42  
43      <T> T computeIfAbsent(String groupId, String artifactId, String version, String tag, Supplier<T> data);
44  
45      <T> T computeIfAbsent(Source path, String tag, Supplier<T> data);
46  
47      void clear();
48  }