001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.eclipse.aether.spi.connector.transport.http;
020
021import java.util.Map;
022import java.util.function.Function;
023
024/**
025 * Checksum extractor. Uses all known {@link ChecksumExtractorStrategy} components to extract included checksums,
026 * first extractor returning non-empty value wins.
027 *
028 * @since 2.0.0
029 */
030public interface ChecksumExtractor {
031    /**
032     * Extract checksums using given getter, if possible, or {@code null}.
033     * <p>
034     * The supplied {@code headerGetter} function should provide access to given transport response HTTP Headers in
035     * some common way, like for example returning first header value, or {@code null} if header not present.
036     *
037     * @param headerGetter A function that provides access to response HTTP Headers, never {@code null}.
038     * @return Map of extracted checksums, or {@code null} if none extracted.
039     */
040    Map<String, String> extractChecksums(Function<String, String> headerGetter);
041}