001/*
002 * Copyright 2002-2019 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.web.accept;
018
019import java.util.Collections;
020import java.util.List;
021
022import org.springframework.http.MediaType;
023import org.springframework.util.Assert;
024import org.springframework.web.context.request.NativeWebRequest;
025
026/**
027 * A {@code ContentNegotiationStrategy} that returns a fixed content type.
028 *
029 * @author Rossen Stoyanchev
030 * @since 3.2
031 */
032public class FixedContentNegotiationStrategy implements ContentNegotiationStrategy {
033
034        private final List<MediaType> contentTypes;
035
036
037        /**
038         * Constructor with a single default {@code MediaType}.
039         */
040        public FixedContentNegotiationStrategy(MediaType contentType) {
041                this(Collections.singletonList(contentType));
042        }
043
044        /**
045         * Constructor with an ordered List of default {@code MediaType}'s to return
046         * for use in applications that support a variety of content types.
047         * <p>Consider appending {@link MediaType#ALL} at the end if destinations
048         * are present which do not support any of the other default media types.
049         * @since 5.0
050         */
051        public FixedContentNegotiationStrategy(List<MediaType> contentTypes) {
052                Assert.notNull(contentTypes, "'contentTypes' must not be null");
053                this.contentTypes = Collections.unmodifiableList(contentTypes);
054        }
055
056
057        /**
058         * Return the configured list of media types.
059         */
060        public List<MediaType> getContentTypes() {
061                return this.contentTypes;
062        }
063
064
065        @Override
066        public List<MediaType> resolveMediaTypes(NativeWebRequest request) {
067                return this.contentTypes;
068        }
069
070}