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 @SuppressWarnings("deprecation") 93 Object o = Class.forName(cn, true, 94 ClassLoader.getSystemClassLoader()).newInstance(); 95 provider = (HttpServerProvider)o; 96 return true; 97 } catch (ClassNotFoundException | 98 IllegalAccessException | 99 InstantiationException | 100 SecurityException x) { 101 throw new ServiceConfigurationError(null, x); 102 } 103 } 104 105 private static boolean loadProviderAsService() { 106 Iterator<HttpServerProvider> i = 107 ServiceLoader.load(HttpServerProvider.class, 108 ClassLoader.getSystemClassLoader()) 109 .iterator(); 110 for (;;) { 111 try { 112 if (!i.hasNext()) 113 return false; 114 provider = i.next(); 115 return true; 116 } catch (ServiceConfigurationError sce) { 117 if (sce.getCause() instanceof SecurityException) { 118 // Ignore the security exception, try the next provider 119 continue; 120 } 121 throw sce; 122 } 123 } 124 } 125 126 /** 127 * Returns the system wide default HttpServerProvider for this invocation of 128 * the Java virtual machine. 129 * 130 * <p> The first invocation of this method locates the default provider 131 * object as follows: </p> 132 * 133 * <ol> 134 * 135 * <li><p> If the system property 136 * {@code com.sun.net.httpserver.HttpServerProvider} is defined then it 137 * is taken to be the fully-qualified name of a concrete provider class. 138 * The class is loaded and instantiated; if this process fails then an 139 * unspecified unchecked error or exception is thrown. </p></li> 140 * 141 * <li><p> If a provider class has been installed in a jar file that is 142 * visible to the system class loader, and that jar file contains a 143 * provider-configuration file named 144 * {@code com.sun.net.httpserver.HttpServerProvider} in the resource 145 * directory {@code META-INF/services}, then the first class name 146 * specified in that file is taken. The class is loaded and 147 * instantiated; if this process fails then an unspecified unchecked error 148 * or exception is thrown. </p></li> 149 * 150 * <li><p> Finally, if no provider has been specified by any of the above 151 * means then the system-default provider class is instantiated and the 152 * result is returned. </p></li> 153 * 154 * </ol> 155 * 156 * <p> Subsequent invocations of this method return the provider that was 157 * returned by the first invocation. </p> 158 * 159 * @return The system-wide default HttpServerProvider 160 */ 161 public static HttpServerProvider provider () { 162 synchronized (lock) { 163 if (provider != null) 164 return provider; 165 return (HttpServerProvider)AccessController 166 .doPrivileged(new PrivilegedAction<Object>() { 167 public Object run() { 168 if (loadProviderFromProperty()) 169 return provider; 170 if (loadProviderAsService()) 171 return provider; 172 provider = new sun.net.httpserver.DefaultHttpServerProvider(); 173 return provider; 174 } 175 }); 176 } 177 } 178 179 }