/*
* Copyright 2005 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package com.sun.net.httpserver.spi;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Iterator;
import java.util.ServiceLoader;
import java.util.ServiceConfigurationError;
import com.sun.net.httpserver.HttpServer;
import com.sun.net.httpserver.HttpsServer;
/**
* Service provider class for HttpServer.
* Sub-classes of HttpServerProvider provide an implementation of {@link HttpServer} and
* associated classes. Applications do not normally use this class.
* See {@link #provider()} for how providers are found and loaded.
*/
public abstract class HttpServerProvider {
/**
* creates a HttpServer from this provider
* @param addr the address to bind to. May be <code>null</code>
* @param backlog the socket backlog. A value of <code>zero</code> means the systems default
*/
public abstract HttpServer createHttpServer (InetSocketAddress addr, int backlog) throws IOException;
/**
* creates a HttpsServer from this provider
* @param addr the address to bind to. May be <code>null</code>
* @param backlog the socket backlog. A value of <code>zero</code> means the systems default
*/
public abstract HttpsServer createHttpsServer (InetSocketAddress addr, int backlog) throws IOException;
private static final Object lock = new Object();
private static HttpServerProvider provider = null;
/**
* Initializes a new instance of this class. </p>
*
* @throws SecurityException
* If a security manager has been installed and it denies
* {@link RuntimePermission}<tt>("httpServerProvider")</tt>
*/
protected HttpServerProvider() {
SecurityManager sm = System.getSecurityManager();
if (sm != null)
sm.checkPermission(new RuntimePermission("httpServerProvider"));
}
private static boolean loadProviderFromProperty() {
String cn = System.getProperty("com.sun.net.httpserver.HttpServerProvider");
if (cn == null)
return false;
try {
Class c = Class.forName(cn, true,
ClassLoader.getSystemClassLoader());
provider = (HttpServerProvider)c.newInstance();
return true;
} catch (ClassNotFoundException x) {
throw configError(x);
} catch (IllegalAccessException x) {
throw configError(x);
} catch (InstantiationException x) {
throw configError(x);
} catch (SecurityException x) {
throw configError(x);
}
}
private static ServiceConfigurationError configError(final Throwable x) {
final ServiceConfigurationError error = new ServiceConfigurationError(x.getMessage());
error.initCause(x);
return error;
}
private static boolean loadProviderAsService() {
final ServiceLoader<HttpServerProvider> loader = ServiceLoader.load(HttpServerProvider.class, null);
final Iterator<HttpServerProvider> i = loader.iterator();
while (i.hasNext()) {
try {
provider = i.next();
return true;
} catch (ServiceConfigurationError sce) {
if (sce.getCause() instanceof SecurityException) {
// Ignore the security exception, try the next provider
continue;
}
throw sce;
}
}
return false;
}
/**
* Returns the system wide default HttpServerProvider for this invocation of
* the Java virtual machine.
*
* <p> The first invocation of this method locates the default provider
* object as follows: </p>
*
* <ol>
*
* <li><p> If the system property
* <tt>com.sun.net.httpserver.HttpServerProvider</tt> is defined then it is
* taken to be the fully-qualified name of a concrete provider class.
* The class is loaded and instantiated; if this process fails then an
* unspecified unchecked error or exception is thrown. </p></li>
*
* <li><p> If a provider class has been installed in a jar file that is
* visible to the system class loader, and that jar file contains a
* provider-configuration file named
* <tt>com.sun.net.httpserver.HttpServerProvider</tt> in the resource
* directory <tt>META-INF/services</tt>, then the first class name
* specified in that file is taken. The class is loaded and
* instantiated; if this process fails then an unspecified unchecked error or exception is
* thrown. </p></li>
*
* <li><p> Finally, if no provider has been specified by any of the above
* means then the system-default provider class is instantiated and the
* result is returned. </p></li>
*
* </ol>
*
* <p> Subsequent invocations of this method return the provider that was
* returned by the first invocation. </p>
*
* @return The system-wide default HttpServerProvider
*/
public static HttpServerProvider provider () {
synchronized (lock) {
if (provider != null)
return provider;
return (HttpServerProvider)AccessController
.doPrivileged(new PrivilegedAction<Object>() {
public Object run() {
if (loadProviderFromProperty())
return provider;
if (loadProviderAsService())
return provider;
provider = new org.jboss.sun.net.httpserver.DefaultHttpServerProvider();
return provider;
}
});
}
}
}