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;
20
21 /**
22 * Caches auxiliary data used during repository access like already processed metadata. The data in the cache is meant
23 * for exclusive consumption by the repository system and is opaque to the cache implementation. <strong>Note:</strong>
24 * Actual cache implementations must be thread-safe.
25 *
26 * @see RepositorySystemSession#getCache()
27 */
28 public interface RepositoryCache {
29
30 /**
31 * Puts the specified data into the cache. It is entirely up to the cache implementation how long this data will be
32 * kept before being purged, i.e. callers must not make any assumptions about the lifetime of cached data.
33 * <p>
34 * <em>Warning:</em> The cache will directly save the provided reference. If the cached data is mutable, i.e. could
35 * be modified after being put into the cache, the caller is responsible for creating a copy of the original data
36 * and store the copy in the cache.
37 *
38 * @param session The repository session during which the cache is accessed, must not be {@code null}.
39 * @param key The key to use for lookup of the data, must not be {@code null}.
40 * @param data The data to store in the cache, may be {@code null}.
41 */
42 void put(RepositorySystemSession session, Object key, Object data);
43
44 /**
45 * Gets the specified data from the cache.
46 * <p>
47 * <em>Warning:</em> The cache will directly return the saved reference. If the cached data is to be modified after
48 * its retrieval, the caller is responsible to create a copy of the returned data and use this instead of the cache
49 * record.
50 *
51 * @param session The repository session during which the cache is accessed, must not be {@code null}.
52 * @param key The key to use for lookup of the data, must not be {@code null}.
53 * @return The requested data or {@code null} if none was present in the cache.
54 */
55 Object get(RepositorySystemSession session, Object key);
56 }