1 /*
2  * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License").
5  * You may not use this file except in compliance with the License.
6  * A copy of the License is located at
7  *
8  *  http://aws.amazon.com/apache2.0
9  *
10  * or in the "license" file accompanying this file. This file is distributed
11  * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
12  * express or implied. See the License for the specific language governing
13  * permissions and limitations under the License.
14  */
15 
16 package software.amazon.awssdk.http.auth.aws.internal.signer.chunkedencoding;
17 
18 import java.util.List;
19 import software.amazon.awssdk.annotations.SdkInternalApi;
20 import software.amazon.awssdk.utils.Pair;
21 
22 /**
23  * A functional interface for defining a trailer, where the trailer is a header pair.
24  * <p>
25  * A trailer usually depends on the chunk-data itself (checksum, signature, etc.), but is not required to. Per <a
26  * href="https://datatracker.ietf.org/doc/html/rfc7230#section-4.1.2">RFC-7230</a>, the chunked trailer section is defined as:
27  * <pre>
28  *     trailer-part   = *( header-field CRLF )
29  * </pre>
30  * An implementation of this interface is specifically an element of the {@code trailer-part}. Therefore, all occurrences of
31  * {@code TrailerProvider}'s make up the {@code trailer-part}.
32  */
33 @FunctionalInterface
34 @SdkInternalApi
35 public interface TrailerProvider extends Resettable {
get()36     Pair<String, List<String>> get();
37 }
38