FsUrlStreamHandlerFactory.java
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上传日期:2018-01-08
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文件大小:3k
源码类别:
网格计算
开发平台:
Java
- /**
- * 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.net.URLStreamHandlerFactory;
- import java.util.HashMap;
- import java.util.Map;
- 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.
- */
- public class FsUrlStreamHandlerFactory implements
- URLStreamHandlerFactory {
- // 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 HashMap<String, Boolean>();
- // The URL Stream handler
- private java.net.URLStreamHandler handler;
- public FsUrlStreamHandlerFactory() {
- this.conf = new Configuration();
- // force the resolution of the configuration files
- // this is required if we want the factory to be able to handle
- // file:// URLs
- this.conf.getClass("fs.file.impl", null);
- this.handler = new FsUrlStreamHandler(this.conf);
- }
- public FsUrlStreamHandlerFactory(Configuration conf) {
- this.conf = new Configuration(conf);
- // force the resolution of the configuration files
- this.conf.getClass("fs.file.impl", null);
- this.handler = new FsUrlStreamHandler(this.conf);
- }
- public java.net.URLStreamHandler createURLStreamHandler(String protocol) {
- if (!protocols.containsKey(protocol)) {
- boolean known =
- (conf.getClass("fs." + protocol + ".impl", null) != null);
- protocols.put(protocol, known);
- }
- if (protocols.get(protocol)) {
- return handler;
- } else {
- // FileSystem does not know the protocol, let the VM handle this
- return null;
- }
- }
- }