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.http.impl.execchain;
29
30 import java.io.IOException;
31
32 import org.apache.http.HttpException;
33 import org.apache.http.client.methods.CloseableHttpResponse;
34 import org.apache.http.client.methods.HttpExecutionAware;
35 import org.apache.http.client.methods.HttpRequestWrapper;
36 import org.apache.http.client.protocol.HttpClientContext;
37 import org.apache.http.conn.routing.HttpRoute;
38
39 /**
40 * This interface represents an element in the HTTP request execution chain. Each element can
41 * either be a decorator around another element that implements a cross cutting aspect or
42 * a self-contained executor capable of producing a response for the given request.
43 * <p>
44 * Important: please note it is required for decorators that implement post execution aspects
45 * or response post-processing of any sort to release resources associated with the response
46 * by calling {@link CloseableHttpResponse#close()} methods in case of an I/O, protocol or
47 * runtime exception, or in case the response is not propagated to the caller.
48 * </p>
49 *
50 * @since 4.3
51 */
52 public interface ClientExecChain {
53
54 /**
55 * Executes th request either by transmitting it to the target server or
56 * by passing it onto the next executor in the request execution chain.
57 *
58 * @param route connection route.
59 * @param request current request.
60 * @param clientContext current HTTP context.
61 * @param execAware receiver of notifications of blocking I/O operations.
62 * @return HTTP response either received from the opposite endpoint
63 * or generated locally.
64 * @throws IOException in case of a I/O error.
65 * (this type of exceptions are potentially recoverable).
66 * @throws HttpException in case of an HTTP protocol error
67 * (usually this type of exceptions are non-recoverable).
68 */
69 CloseableHttpResponse execute(
70 HttpRoute route,
71 HttpRequestWrapper request,
72 HttpClientContext clientContext,
73 HttpExecutionAware execAware) throws IOException, HttpException;
74
75 }