| /** |
| * 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 org.apache.hadoop.fs; |
| |
| import java.io.IOException; |
| import java.net.URLStreamHandlerFactory; |
| import java.util.Map; |
| import java.util.concurrent.ConcurrentHashMap; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.apache.hadoop.conf.Configuration; |
| |
| /** |
| * Factory for URL stream handlers. |
| * |
| * There is only one handler whose job is to create UrlConnections. A |
| * FsUrlConnection relies on FileSystem to choose the appropriate FS |
| * implementation. |
| * |
| * Before returning our handler, we make sure that FileSystem knows an |
| * implementation for the requested scheme/protocol. |
| */ |
| @InterfaceAudience.Private |
| @InterfaceStability.Unstable |
| public class FsUrlStreamHandlerFactory implements |
| URLStreamHandlerFactory { |
| |
| private static final Logger LOG = |
| LoggerFactory.getLogger(FsUrlStreamHandlerFactory.class); |
| |
| /** |
| * These are the protocols with MUST NOT be exported, as doing so |
| * would conflict with the standard URL handlers registered by |
| * the JVM. Many things will break. |
| */ |
| public static final String[] UNEXPORTED_PROTOCOLS = { |
| "http", "https" |
| }; |
| |
| // The configuration holds supported FS implementation class names. |
| private Configuration conf; |
| |
| // This map stores whether a protocol is know or not by FileSystem |
| private Map<String, Boolean> protocols = |
| new ConcurrentHashMap<String, Boolean>(); |
| |
| // The URL Stream handler |
| private java.net.URLStreamHandler handler; |
| |
| public FsUrlStreamHandlerFactory() { |
| this(new Configuration()); |
| } |
| |
| public FsUrlStreamHandlerFactory(Configuration conf) { |
| this.conf = new Configuration(conf); |
| // force init of FileSystem code to avoid HADOOP-9041 |
| try { |
| FileSystem.getFileSystemClass("file", conf); |
| } catch (IOException io) { |
| throw new RuntimeException(io); |
| } |
| this.handler = new FsUrlStreamHandler(this.conf); |
| for (String protocol : UNEXPORTED_PROTOCOLS) { |
| protocols.put(protocol, false); |
| } |
| } |
| |
| @Override |
| public java.net.URLStreamHandler createURLStreamHandler(String protocol) { |
| LOG.debug("Creating handler for protocol {}", protocol); |
| if (!protocols.containsKey(protocol)) { |
| boolean known = true; |
| try { |
| Class<? extends FileSystem> impl |
| = FileSystem.getFileSystemClass(protocol, conf); |
| LOG.debug("Found implementation of {}: {}", protocol, impl); |
| } |
| catch (IOException ex) { |
| known = false; |
| } |
| protocols.put(protocol, known); |
| } |
| if (protocols.get(protocol)) { |
| LOG.debug("Using handler for protocol {}", protocol); |
| return handler; |
| } else { |
| // FileSystem does not know the protocol, let the VM handle this |
| LOG.debug("Unknown protocol {}, delegating to default implementation", |
| protocol); |
| return null; |
| } |
| } |
| |
| } |