1 /*
2 * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package com.sun.net.httpserver.spi;
27
28 import java.io.IOException;
29 import java.net.*;
30 import java.security.AccessController;
31 import java.security.PrivilegedAction;
32 import java.util.Iterator;
33 import java.util.ServiceLoader;
34 import java.util.ServiceConfigurationError;
35 import com.sun.net.httpserver.*;
36
37 /**
38 * Service provider class for HttpServer.
39 * Sub-classes of HttpServerProvider provide an implementation of
40 * {@link HttpServer} and associated classes. Applications do not normally use
41 * this class. See {@link #provider()} for how providers are found and loaded.
42 */
43 public abstract class HttpServerProvider {
44
45 /**
46 * creates a HttpServer from this provider
47 *
48 * @param addr
49 * the address to bind to. May be {@code null}
50 *
51 * @param backlog
52 * the socket backlog. A value of {@code zero} means the systems default
53 */
54 public abstract HttpServer createHttpServer(InetSocketAddress addr,
55 int backlog)
56 throws IOException;
57
58 /**
59 * creates a HttpsServer from this provider
60 *
61 * @param addr
62 * the address to bind to. May be {@code null}
63 *
64 * @param backlog
65 * the socket backlog. A value of {@code zero} means the systems default
66 */
67 public abstract HttpsServer createHttpsServer(InetSocketAddress addr,
68 int backlog)
69 throws IOException;
70
71 private static final Object lock = new Object();
72 private static HttpServerProvider provider = null;
73
74 /**
75 * Initializes a new instance of this class.
76 *
77 * @throws SecurityException
78 * If a security manager has been installed and it denies
79 * {@link RuntimePermission}{@code ("httpServerProvider")}
80 */
81 protected HttpServerProvider() {
82 SecurityManager sm = System.getSecurityManager();
83 if (sm != null)
84 sm.checkPermission(new RuntimePermission("httpServerProvider"));
85 }
86
87 private static boolean loadProviderFromProperty() {
88 String cn = System.getProperty("com.sun.net.httpserver.HttpServerProvider");
89 if (cn == null)
90 return false;
91 try {
92 Class<?> c = Class.forName(cn, true,
93 ClassLoader.getSystemClassLoader());
94 provider = (HttpServerProvider)c.newInstance();
95 return true;
96 } catch (ClassNotFoundException |
97 IllegalAccessException |
98 InstantiationException |
99 SecurityException x) {
100 throw new ServiceConfigurationError(null, x);
101 }
102 }
103
104 private static boolean loadProviderAsService() {
105 Iterator<HttpServerProvider> i =
106 ServiceLoader.load(HttpServerProvider.class,
107 ClassLoader.getSystemClassLoader())
108 .iterator();
109 for (;;) {
110 try {
111 if (!i.hasNext())
112 return false;
113 provider = i.next();
114 return true;
115 } catch (ServiceConfigurationError sce) {
116 if (sce.getCause() instanceof SecurityException) {
117 // Ignore the security exception, try the next provider
118 continue;
119 }
120 throw sce;
121 }
122 }
123 }
124
125 /**
126 * Returns the system wide default HttpServerProvider for this invocation of
127 * the Java virtual machine.
128 *
129 * <p> The first invocation of this method locates the default provider
130 * object as follows: </p>
131 *
132 * <ol>
133 *
134 * <li><p> If the system property
135 * {@code com.sun.net.httpserver.HttpServerProvider} is defined then it
136 * is taken to be the fully-qualified name of a concrete provider class.
137 * The class is loaded and instantiated; if this process fails then an
138 * unspecified unchecked error or exception is thrown. </p></li>
139 *
140 * <li><p> If a provider class has been installed in a jar file that is
141 * visible to the system class loader, and that jar file contains a
142 * provider-configuration file named
143 * {@code com.sun.net.httpserver.HttpServerProvider} in the resource
144 * directory {@code META-INF/services}, then the first class name
145 * specified in that file is taken. The class is loaded and
146 * instantiated; if this process fails then an unspecified unchecked error
147 * or exception is thrown. </p></li>
148 *
149 * <li><p> Finally, if no provider has been specified by any of the above
150 * means then the system-default provider class is instantiated and the
151 * result is returned. </p></li>
152 *
153 * </ol>
154 *
155 * <p> Subsequent invocations of this method return the provider that was
156 * returned by the first invocation. </p>
157 *
158 * @return The system-wide default HttpServerProvider
159 */
160 public static HttpServerProvider provider () {
161 synchronized (lock) {
162 if (provider != null)
163 return provider;
164 return (HttpServerProvider)AccessController
165 .doPrivileged(new PrivilegedAction<Object>() {
166 public Object run() {
167 if (loadProviderFromProperty())
168 return provider;
169 if (loadProviderAsService())
170 return provider;
171 provider = new sun.net.httpserver.DefaultHttpServerProvider();
172 return provider;
173 }
174 });
175 }
176 }
177
178 }