1 /*
2 * Copyright (c) 2005, 2011, 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.FileDescriptor;
29 import java.io.IOException;
30 import java.net.*;
31 import java.security.AccessController;
32 import java.security.PrivilegedAction;
33 import java.util.Iterator;
34 import sun.misc.Service;
35 import sun.misc.ServiceConfigurationError;
36 import sun.security.action.GetPropertyAction;
37 import com.sun.net.httpserver.*;
38
39 /**
40 * Service provider class for HttpServer.
41 * Sub-classes of HttpServerProvider provide an implementation of {@link HttpServer} and
42 * associated classes. Applications do not normally use this class.
43 * See {@link #provider()} for how providers are found and loaded.
44 */
45 public abstract class HttpServerProvider {
46
47 /**
48 * creates a HttpServer from this provider
49 * @param addr the address to bind to. May be <code>null</code>
50 * @param backlog the socket backlog. A value of <code>zero</code> means the systems default
51 */
52 public abstract HttpServer createHttpServer (InetSocketAddress addr, int backlog) throws IOException;
53
54 /**
55 * creates a HttpsServer from this provider
56 * @param addr the address to bind to. May be <code>null</code>
57 * @param backlog the socket backlog. A value of <code>zero</code> means the systems default
58 */
59 public abstract HttpsServer createHttpsServer (InetSocketAddress addr, int backlog) throws IOException;
60
61
62
63 private static final Object lock = new Object();
64 private static HttpServerProvider provider = null;
65
66 /**
67 * Initializes a new instance of this class. </p>
68 *
69 * @throws SecurityException
70 * If a security manager has been installed and it denies
71 * {@link RuntimePermission}<tt>("httpServerProvider")</tt>
72 */
73 protected HttpServerProvider() {
74 SecurityManager sm = System.getSecurityManager();
75 if (sm != null)
76 sm.checkPermission(new RuntimePermission("httpServerProvider"));
77 }
78
79 private static boolean loadProviderFromProperty() {
80 String cn = System.getProperty("com.sun.net.httpserver.HttpServerProvider");
81 if (cn == null)
82 return false;
83 try {
84 Class<?> c = Class.forName(cn, true,
85 ClassLoader.getSystemClassLoader());
86 provider = (HttpServerProvider)c.newInstance();
87 return true;
88 } catch (ClassNotFoundException x) {
89 throw new ServiceConfigurationError(x);
90 } catch (InstantiationException x) {
91 throw new ServiceConfigurationError(x);
92 } catch (IllegalAccessException x) {
93 throw new ServiceConfigurationError(x);
94 } catch (SecurityException x) {
95 throw new ServiceConfigurationError(x);
96 }
97 }
98
99 private static boolean loadProviderAsService() {
100 @SuppressWarnings("unchecked")
101 Iterator<HttpServerProvider> i = Service.providers(HttpServerProvider.class,
102 ClassLoader.getSystemClassLoader());
103 for (;;) {
104 try {
105 if (!i.hasNext())
106 return false;
107 provider = i.next();
108 return true;
109 } catch (ServiceConfigurationError sce) {
110 if (sce.getCause() instanceof SecurityException) {
111 // Ignore the security exception, try the next provider
112 continue;
113 }
114 throw sce;
115 }
116 }
117 }
118
119 /**
120 * Returns the system wide default HttpServerProvider for this invocation of
121 * the Java virtual machine.
122 *
123 * <p> The first invocation of this method locates the default provider
124 * object as follows: </p>
125 *
126 * <ol>
127 *
128 * <li><p> If the system property
129 * <tt>com.sun.net.httpserver.HttpServerProvider</tt> is defined then it is
130 * taken to be the fully-qualified name of a concrete provider class.
131 * The class is loaded and instantiated; if this process fails then an
132 * unspecified unchecked error or exception is thrown. </p></li>
133 *
134 * <li><p> If a provider class has been installed in a jar file that is
135 * visible to the system class loader, and that jar file contains a
136 * provider-configuration file named
137 * <tt>com.sun.net.httpserver.HttpServerProvider</tt> in the resource
138 * directory <tt>META-INF/services</tt>, then the first class name
139 * specified in that file is taken. The class is loaded and
140 * instantiated; if this process fails then an unspecified unchecked error or exception is
141 * thrown. </p></li>
142 *
143 * <li><p> Finally, if no provider has been specified by any of the above
144 * means then the system-default provider class is instantiated and the
145 * result is returned. </p></li>
146 *
147 * </ol>
148 *
149 * <p> Subsequent invocations of this method return the provider that was
150 * returned by the first invocation. </p>
151 *
152 * @return The system-wide default HttpServerProvider
153 */
154 public static HttpServerProvider provider () {
155 synchronized (lock) {
156 if (provider != null)
157 return provider;
158 return (HttpServerProvider)AccessController
159 .doPrivileged(new PrivilegedAction<Object>() {
160 public Object run() {
161 if (loadProviderFromProperty())
162 return provider;
163 if (loadProviderAsService())
164 return provider;
165 provider = new sun.net.httpserver.DefaultHttpServerProvider();
166 return provider;
167 }
168 });
169 }
170 }
171
172 }