| /** |
| * 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.hdfs.server.namenode; |
| |
| import java.io.IOException; |
| import java.util.Iterator; |
| import java.util.NoSuchElementException; |
| import java.util.Optional; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.apache.hadoop.hdfs.protocol.Block; |
| import org.apache.hadoop.hdfs.server.common.FileRegion; |
| import org.apache.hadoop.hdfs.server.common.blockaliasmap.BlockAliasMap; |
| |
| /** |
| * Null sink for region information emitted from FSImage. |
| */ |
| @InterfaceAudience.Public |
| @InterfaceStability.Unstable |
| public class NullBlockAliasMap extends BlockAliasMap<FileRegion> { |
| |
| @Override |
| public Reader<FileRegion> getReader(Reader.Options opts, String blockPoolID) |
| throws IOException { |
| return new Reader<FileRegion>() { |
| @Override |
| public Iterator<FileRegion> iterator() { |
| return new Iterator<FileRegion>() { |
| @Override |
| public boolean hasNext() { |
| return false; |
| } |
| @Override |
| public FileRegion next() { |
| throw new NoSuchElementException(); |
| } |
| @Override |
| public void remove() { |
| throw new UnsupportedOperationException(); |
| } |
| }; |
| } |
| |
| @Override |
| public void close() throws IOException { |
| // do nothing |
| } |
| |
| @Override |
| public Optional<FileRegion> resolve(Block ident) throws IOException { |
| throw new UnsupportedOperationException(); |
| } |
| }; |
| } |
| |
| @Override |
| public Writer getWriter(Writer.Options opts, String blockPoolID) |
| throws IOException { |
| return new Writer<FileRegion>() { |
| @Override |
| public void store(FileRegion token) throws IOException { |
| // do nothing |
| } |
| |
| @Override |
| public void close() throws IOException { |
| // do nothing |
| } |
| }; |
| } |
| |
| @Override |
| public void refresh() throws IOException { |
| // do nothing |
| } |
| |
| @Override |
| public void close() throws IOException { |
| |
| } |
| } |