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.spi.connector.checksum;
20
21 import java.util.List;
22 import java.util.Map;
23
24 import org.eclipse.aether.RepositorySystemSession;
25 import org.eclipse.aether.spi.connector.ArtifactDownload;
26
27 /**
28 * Component able to provide (expected) checksums to connector beforehand the download happens. Checksum provided by
29 * this component are of kind {@link org.eclipse.aether.spi.connector.checksum.ChecksumPolicy.ChecksumKind#PROVIDED}.
30 *
31 * @since 1.8.0
32 */
33 public interface ProvidedChecksumsSource {
34 /**
35 * May return the provided checksums (for given artifact transfer) from source other than remote repository, or
36 * {@code null} if it have no checksums available for given transfer. Provided checksums are "opt-in" for
37 * transfer, in a way IF they are available upfront, they will be enforced according to checksum policy
38 * in effect. Otherwise, provided checksum verification is completely left out.
39 * <p>
40 * For enabled provided checksum source is completely acceptable to return {@code null} values, as that carries
41 * the meaning "nothing to add here", as there are no checksums to be provided upfront transfer. Semantically, this
42 * is equivalent to returning empty map, but signals the intent better.
43 *
44 * @param transfer The transfer that is about to be executed.
45 * @param checksumAlgorithmFactories The checksum algorithms that are expected.
46 * @return Map of expected checksums, or {@code null}.
47 */
48 Map<String, String> getProvidedArtifactChecksums(
49 RepositorySystemSession session,
50 ArtifactDownload transfer,
51 List<ChecksumAlgorithmFactory> checksumAlgorithmFactories);
52 }