001/*
002 * Copyright 2002-2018 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.http;
018
019import org.springframework.lang.Nullable;
020import org.springframework.util.MultiValueMap;
021import org.springframework.util.ObjectUtils;
022
023/**
024 * Represents an HTTP request or response entity, consisting of headers and body.
025 *
026 * <p>Typically used in combination with the {@link org.springframework.web.client.RestTemplate},
027 * like so:
028 * <pre class="code">
029 * HttpHeaders headers = new HttpHeaders();
030 * headers.setContentType(MediaType.TEXT_PLAIN);
031 * HttpEntity&lt;String&gt; entity = new HttpEntity&lt;String&gt;(helloWorld, headers);
032 * URI location = template.postForLocation("https://example.com", entity);
033 * </pre>
034 * or
035 * <pre class="code">
036 * HttpEntity&lt;String&gt; entity = template.getForEntity("https://example.com", String.class);
037 * String body = entity.getBody();
038 * MediaType contentType = entity.getHeaders().getContentType();
039 * </pre>
040 * Can also be used in Spring MVC, as a return value from a @Controller method:
041 * <pre class="code">
042 * &#64;RequestMapping("/handle")
043 * public HttpEntity&lt;String&gt; handle() {
044 *   HttpHeaders responseHeaders = new HttpHeaders();
045 *   responseHeaders.set("MyResponseHeader", "MyValue");
046 *   return new HttpEntity&lt;String&gt;("Hello World", responseHeaders);
047 * }
048 * </pre>
049 *
050 * @author Arjen Poutsma
051 * @author Juergen Hoeller
052 * @since 3.0.2
053 * @param <T> the body type
054 * @see org.springframework.web.client.RestTemplate
055 * @see #getBody()
056 * @see #getHeaders()
057 */
058public class HttpEntity<T> {
059
060        /**
061         * The empty {@code HttpEntity}, with no body or headers.
062         */
063        public static final HttpEntity<?> EMPTY = new HttpEntity<>();
064
065
066        private final HttpHeaders headers;
067
068        @Nullable
069        private final T body;
070
071
072        /**
073         * Create a new, empty {@code HttpEntity}.
074         */
075        protected HttpEntity() {
076                this(null, null);
077        }
078
079        /**
080         * Create a new {@code HttpEntity} with the given body and no headers.
081         * @param body the entity body
082         */
083        public HttpEntity(T body) {
084                this(body, null);
085        }
086
087        /**
088         * Create a new {@code HttpEntity} with the given headers and no body.
089         * @param headers the entity headers
090         */
091        public HttpEntity(MultiValueMap<String, String> headers) {
092                this(null, headers);
093        }
094
095        /**
096         * Create a new {@code HttpEntity} with the given body and headers.
097         * @param body the entity body
098         * @param headers the entity headers
099         */
100        public HttpEntity(@Nullable T body, @Nullable MultiValueMap<String, String> headers) {
101                this.body = body;
102                HttpHeaders tempHeaders = new HttpHeaders();
103                if (headers != null) {
104                        tempHeaders.putAll(headers);
105                }
106                this.headers = HttpHeaders.readOnlyHttpHeaders(tempHeaders);
107        }
108
109
110        /**
111         * Returns the headers of this entity.
112         */
113        public HttpHeaders getHeaders() {
114                return this.headers;
115        }
116
117        /**
118         * Returns the body of this entity.
119         */
120        @Nullable
121        public T getBody() {
122                return this.body;
123        }
124
125        /**
126         * Indicates whether this entity has a body.
127         */
128        public boolean hasBody() {
129                return (this.body != null);
130        }
131
132
133        @Override
134        public boolean equals(@Nullable Object other) {
135                if (this == other) {
136                        return true;
137                }
138                if (other == null || other.getClass() != getClass()) {
139                        return false;
140                }
141                HttpEntity<?> otherEntity = (HttpEntity<?>) other;
142                return (ObjectUtils.nullSafeEquals(this.headers, otherEntity.headers) &&
143                                ObjectUtils.nullSafeEquals(this.body, otherEntity.body));
144        }
145
146        @Override
147        public int hashCode() {
148                return (ObjectUtils.nullSafeHashCode(this.headers) * 29 + ObjectUtils.nullSafeHashCode(this.body));
149        }
150
151        @Override
152        public String toString() {
153                StringBuilder builder = new StringBuilder("<");
154                if (this.body != null) {
155                        builder.append(this.body);
156                        builder.append(',');
157                }
158                builder.append(this.headers);
159                builder.append('>');
160                return builder.toString();
161        }
162
163}