| /* |
| * Copyright (c) 2009, 2011, Oracle and/or its affiliates. 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. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| package sun.net.ftp; |
| |
| import java.security.AccessController; |
| import java.security.PrivilegedAction; |
| import java.util.ServiceConfigurationError; |
| //import java.util.ServiceLoader; |
| |
| /** |
| * Service provider class for FtpClient. |
| * Sub-classes of FtpClientProvider provide an implementation of {@link FtpClient} |
| * and associated classes. Applications do not normally use this class directly. |
| * See {@link #provider() } for how providers are found and loaded. |
| * |
| * @since 1.7 |
| */ |
| public abstract class FtpClientProvider { |
| |
| /** |
| * Creates a FtpClient from this provider. |
| * |
| * @return The created {@link FtpClient}. |
| */ |
| public abstract FtpClient createFtpClient(); |
| private static final Object lock = new Object(); |
| private static FtpClientProvider provider = null; |
| |
| /** |
| * Initializes a new instance of this class. |
| * |
| * @throws SecurityException if a security manager is installed and it denies |
| * {@link RuntimePermission}{@code ("ftpClientProvider")} |
| */ |
| protected FtpClientProvider() { |
| SecurityManager sm = System.getSecurityManager(); |
| if (sm != null) { |
| sm.checkPermission(new RuntimePermission("ftpClientProvider")); |
| } |
| } |
| |
| private static boolean loadProviderFromProperty() { |
| String cm = System.getProperty("sun.net.ftpClientProvider"); |
| if (cm == null) { |
| return false; |
| } |
| try { |
| @SuppressWarnings("deprecation") |
| Object o = Class.forName(cm, true, null).newInstance(); |
| provider = (FtpClientProvider)o; |
| return true; |
| } catch (ClassNotFoundException | |
| IllegalAccessException | |
| InstantiationException | |
| SecurityException x) { |
| throw new ServiceConfigurationError(x.toString()); |
| } |
| } |
| |
| private static boolean loadProviderAsService() { |
| // Iterator<FtpClientProvider> i = |
| // ServiceLoader.load(FtpClientProvider.class, |
| // ClassLoader.getSystemClassLoader()).iterator(); |
| // |
| // while (i.hasNext()) { |
| // try { |
| // provider = i.next(); |
| // return true; |
| // } catch (ServiceConfigurationError sce) { |
| // if (sce.getCause() instanceof SecurityException) { |
| // // Ignore, try next provider, if any |
| // continue; |
| // } |
| // throw sce; |
| // } |
| // } |
| return false; |
| } |
| |
| /** |
| * Returns the system wide default FtpClientProvider 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 |
| * {@code java.net.FtpClientProvider} 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 |
| * {@code java.net.FtpClientProvider} in the resource |
| * directory {@code META-INF/services}, 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 FtpClientProvider |
| */ |
| public static FtpClientProvider provider() { |
| synchronized (lock) { |
| if (provider != null) { |
| return provider; |
| } |
| return (FtpClientProvider) AccessController.doPrivileged( |
| new PrivilegedAction<Object>() { |
| |
| public Object run() { |
| if (loadProviderFromProperty()) { |
| return provider; |
| } |
| if (loadProviderAsService()) { |
| return provider; |
| } |
| provider = new sun.net.ftp.impl.DefaultFtpClientProvider(); |
| return provider; |
| } |
| }); |
| } |
| } |
| } |