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.routing;
29
30 import org.apache.hc.client5.http.HttpRoute;
31 import org.apache.hc.core5.annotation.Contract;
32 import org.apache.hc.core5.annotation.ThreadingBehavior;
33 import org.apache.hc.core5.http.HttpException;
34 import org.apache.hc.core5.http.HttpHost;
35 import org.apache.hc.core5.http.HttpRequest;
36 import org.apache.hc.core5.http.protocol.HttpContext;
37
38 /**
39 * Encapsulates logic to compute a {@link HttpRoute} to a target host.
40 * Implementations may for example be based on parameters, or on the
41 * standard Java system properties.
42 * <p>
43 * Implementations of this interface must be thread-safe. Access to shared
44 * data must be synchronized as methods of this interface may be executed
45 * from multiple threads.
46 * </p>
47 *
48 * @since 4.0
49 */
50 @Contract(threading = ThreadingBehavior.STATELESS)
51 public interface HttpRoutePlanner {
52
53 /**
54 * Determines the route for the given host.
55 *
56 * @param target the target host for the request.
57 * @param context the context to use for the subsequent execution.
58 * Implementations may accept {@code null}.
59 *
60 * @return the route that the request should take
61 *
62 * @throws HttpException in case of a problem
63 */
64 HttpRoute determineRoute(HttpHost target, HttpContext context) throws HttpException;
65
66 /**
67 * Determines the route for the given host.
68 *
69 * @param target the target host for the request.
70 * @param request the request message. Can be {@code null} if not given / known.
71 * @param context the context to use for the subsequent execution.
72 * Implementations may accept {@code null}.
73 *
74 * @return the route that the request should take
75 * @throws HttpException in case of a problem.
76 *
77 * @since 5.4
78 */
79 default HttpRoute determineRoute(HttpHost target, HttpRequest request, HttpContext context) throws HttpException {
80 return determineRoute(target, context);
81 }
82
83 }