1 /*
2 * ====================================================================
3 * Licensed to the Apache Software Foundation (ASF) under one
4 * or more contributor license agreements. See the NOTICE file
5 * distributed with this work for additional information
6 * regarding copyright ownership. The ASF licenses this file
7 * to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance
9 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing,
14 * software distributed under the License is distributed on an
15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16 * KIND, either express or implied. See the License for the
17 * specific language governing permissions and limitations
18 * under the License.
19 * ====================================================================
20 *
21 * This software consists of voluntary contributions made by many
22 * individuals on behalf of the Apache Software Foundation. For more
23 * information on the Apache Software Foundation, please see
24 * <http://www.apache.org/>.
25 *
26 */
27
28 package org.apache.hc.client5.http.impl.classic;
29
30 import java.io.IOException;
31
32 import org.apache.hc.client5.http.HttpResponseException;
33 import org.apache.hc.core5.annotation.Contract;
34 import org.apache.hc.core5.annotation.ThreadingBehavior;
35 import org.apache.hc.core5.http.ClassicHttpResponse;
36 import org.apache.hc.core5.http.HttpEntity;
37 import org.apache.hc.core5.http.HttpStatus;
38 import org.apache.hc.core5.http.io.HttpClientResponseHandler;
39 import org.apache.hc.core5.http.io.entity.EntityUtils;
40
41 /**
42 * A generic {@link HttpClientResponseHandler} that works with the response entity
43 * for successful (2xx) responses. If the response code was >= 300, the response
44 * body is consumed and an {@link HttpResponseException} is thrown.
45 * <p>
46 * If this is used with
47 * {@link org.apache.hc.client5.http.classic.HttpClient#execute(
48 * org.apache.hc.core5.http.ClassicHttpRequest, HttpClientResponseHandler)},
49 * HttpClient may handle redirects (3xx responses) internally.
50 * </p>
51 *
52 * @param <T> the type of the value determined by the response.
53 * @since 4.4
54 */
55 @Contract(threading = ThreadingBehavior.STATELESS)
56 public abstract class AbstractHttpClientResponseHandler<T> implements HttpClientResponseHandler<T> {
57
58 /**
59 * Read the entity from the response body and pass it to the entity handler
60 * method if the response was successful (a 2xx status code). If no response
61 * body exists, this returns null. If the response was unsuccessful (>= 300
62 * status code), throws an {@link HttpResponseException}.
63 */
64 @Override
65 public T handleResponse(final ClassicHttpResponse response) throws IOException {
66 final HttpEntity entity = response.getEntity();
67 if (response.getCode() >= HttpStatus.SC_REDIRECTION) {
68 EntityUtils.consume(entity);
69 throw new HttpResponseException(response.getCode(), response.getReasonPhrase());
70 }
71 return entity == null ? null : handleEntity(entity);
72 }
73
74 /**
75 * Handle the response entity and transform it into the actual response
76 * object.
77 */
78 public abstract T handleEntity(HttpEntity entity) throws IOException;
79
80 }