| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package java.nio.channels.spi; |
| |
| import java.io.IOException; |
| import java.nio.channels.Channel; |
| import java.nio.channels.DatagramChannel; |
| import java.nio.channels.Pipe; |
| import java.nio.channels.ServerSocketChannel; |
| import java.nio.channels.SocketChannel; |
| import java.security.AccessController; |
| import java.security.PrivilegedAction; |
| import java.util.ServiceLoader; |
| import org.apache.harmony.nio.internal.SelectorProviderImpl; |
| |
| /** |
| * {@code SelectorProvider} is an abstract base class that declares methods for |
| * providing instances of {@link DatagramChannel}, {@link Pipe}, |
| * {@link java.nio.channels.Selector} , {@link ServerSocketChannel}, and |
| * {@link SocketChannel}. All the methods of this class are thread-safe. |
| * |
| * <p>A provider instance can be retrieved through a system property or the |
| * configuration file in a jar file; if no provider is available that way then |
| * the system default provider is returned. |
| */ |
| public abstract class SelectorProvider { |
| private static SelectorProvider provider = null; |
| |
| /** |
| * Constructs a new {@code SelectorProvider}. |
| * |
| * @throws SecurityException |
| * if there is a security manager installed that does not permit |
| * the runtime permission labeled "selectorProvider". |
| */ |
| protected SelectorProvider() { |
| super(); |
| if (null != System.getSecurityManager()) { |
| System.getSecurityManager().checkPermission( |
| new RuntimePermission("selectorProvider")); |
| } |
| } |
| |
| /** |
| * Gets a provider instance by executing the following steps when called for |
| * the first time: |
| * <ul> |
| * <li> if the system property "java.nio.channels.spi.SelectorProvider" is |
| * set, the value of this property is the class name of the provider |
| * returned; </li> |
| * <li>if there is a provider-configuration file named |
| * "java.nio.channels.spi.SelectorProvider" in META-INF/services of a jar |
| * file valid in the system class loader, the first class name is the |
| * provider's class name; </li> |
| * <li> otherwise, a system default provider will be returned.</li> |
| * </ul> |
| * |
| * @return the provider. |
| */ |
| synchronized public static SelectorProvider provider() { |
| if (provider == null) { |
| provider = ServiceLoader.loadFromSystemProperty(SelectorProvider.class); |
| if (provider == null) { |
| provider = loadProviderByJar(); |
| } |
| if (provider == null) { |
| provider = AccessController.doPrivileged(new PrivilegedAction<SelectorProvider>() { |
| public SelectorProvider run() { |
| return new SelectorProviderImpl(); |
| } |
| }); |
| } |
| } |
| return provider; |
| } |
| |
| private static SelectorProvider loadProviderByJar() { |
| for (SelectorProvider provider : ServiceLoader.load(SelectorProvider.class, null)) { |
| return provider; |
| } |
| return null; |
| } |
| |
| /** |
| * Creates a new open {@code DatagramChannel}. |
| * |
| * @return the new channel. |
| * @throws IOException |
| * if an I/O error occurs. |
| */ |
| public abstract DatagramChannel openDatagramChannel() throws IOException; |
| |
| /** |
| * Creates a new {@code Pipe}. |
| * |
| * @return the new pipe. |
| * @throws IOException |
| * if an I/O error occurs. |
| */ |
| public abstract Pipe openPipe() throws IOException; |
| |
| /** |
| * Creates a new selector. |
| * |
| * @return the new selector. |
| * @throws IOException |
| * if an I/O error occurs. |
| */ |
| public abstract AbstractSelector openSelector() throws IOException; |
| |
| /** |
| * Creates a new open {@code ServerSocketChannel}. |
| * |
| * @return the new channel. |
| * @throws IOException |
| * if an I/O error occurs. |
| */ |
| public abstract ServerSocketChannel openServerSocketChannel() |
| throws IOException; |
| |
| /** |
| * Create a new open {@code SocketChannel}. |
| * |
| * @return the new channel. |
| * @throws IOException |
| * if an I/O error occurs. |
| */ |
| public abstract SocketChannel openSocketChannel() throws IOException; |
| |
| /** |
| * Returns the channel inherited from the instance that created this |
| * virtual machine. |
| * |
| * @return the channel. |
| * @throws IOException |
| * if an I/O error occurs. |
| * @throws SecurityException |
| * if there is a security manager installed that does not permit |
| * the runtime permission labeled "selectorProvider". |
| */ |
| public Channel inheritedChannel() throws IOException { |
| SecurityManager sm = System.getSecurityManager(); |
| if (sm != null) { |
| sm.checkPermission(new RuntimePermission("inheritedChannel")); |
| } |
| // Android never has stdin/stdout connected to a socket. |
| return null; |
| } |
| } |