1 /**
2 * Copyright (C) 2005-2009 Alfresco Software Limited.
3 *
4 * This file is part of the Spring Surf Extension project.
5 *
6 * Licensed under the Apache License, Version 2.0 (the "License");
7 * you may not use this file except in compliance with the License.
8 * You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18
19 package org.springframework.extensions.webscripts.connector;
20
21 import java.util.concurrent.ConcurrentHashMap;
22 import java.util.concurrent.ConcurrentMap;
23
24 /**
25 * The EndpointManager is responsible for maintaining connection timeout and connection
26 * retry information for endpoints. It may be used by multiple Connector objects to
27 * ensure that shared endpoints are not repeatedly connected to or waited on.
28 *
29 * @author Kevin Roast
30 */
31 public final class EndpointManager
32 {
33 /** timeout value in milliseconds before a reconnection
34 to a particular endpoint should be attempted */
35 private static final int RECONNECT_TIMEOUT = 20000;
36
37 /** conncurrent map of endpoint->timeout values */
38 private static ConcurrentMap<String, Long> endpointTimeouts = new ConcurrentHashMap<String, Long>();
39
40
41 /**
42 * Private constructor
43 */
44 private EndpointManager()
45 {
46 }
47
48
49 /**
50 * Register an endpoint with the manager - the same endpoint can be registered
51 * any number of times with side effects.
52 *
53 * @param endpoint The endpoint to register
54 */
55 public static void registerEndpoint(String endpoint)
56 {
57 endpointTimeouts.putIfAbsent(endpoint, 0L);
58 }
59
60 /**
61 * Returns true if the connector should make a connection attempt to the specified
62 * endpoint, false if the endpoint is still in the "wait" period between retries.
63 *
64 * @param endpoint The endpoint to test
65 *
66 * @return true to allow connect, false otherwise
67 */
68 public static boolean allowConnect(String endpoint)
69 {
70 return (endpointTimeouts.get(endpoint) + RECONNECT_TIMEOUT < System.currentTimeMillis());
71 }
72
73 /**
74 * Process the given response code for an endpoint - recording if that remote
75 * connection is unavailable for a time. Returns true if further response
76 * processing should continue, false otherwise.
77 *
78 * @param endpoint The endpoint to record code against
79 * @param code Response code
80 *
81 * @return true if further processing should continue, false otherwise
82 */
83 public static boolean processResponseCode(String endpoint, int code)
84 {
85 boolean allowContinue = true;;
86
87 if (RemoteClient.SC_REMOTE_CONN_NOHOST == code ||
88 RemoteClient.SC_REMOTE_CONN_TIMEOUT == code)
89 {
90 // If special error codes were returned, don't check the remote connection
91 // again for a short time. This is to ensure that if an endpoint is not
92 // currently available, we don't continually connect+timeout potentially
93 // 100's of times in a row therefore slowing the server startup etc.
94 endpointTimeouts.put(endpoint, System.currentTimeMillis());
95 allowContinue = false;
96 }
97
98 return allowContinue;
99 }
100 }