1 /** 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 package org.apache.hadoop.hdfs; 19 20 import java.io.IOException; 21 import java.util.ArrayList; 22 23 import org.apache.hadoop.conf.Configuration; 24 import org.apache.hadoop.hdfs.DFSClient.DFSOutputStream; 25 import org.apache.hadoop.hdfs.server.namenode.DatanodeDescriptor; 26 import org.apache.hadoop.fs.FSDataOutputStream; 27 import org.apache.hadoop.fs.FileSystem; 28 import org.apache.hadoop.fs.Path; 29 30 import junit.framework.TestCase; 31 32 /** 33 * This class tests DatanodeDescriptor.getBlocksScheduled() at the 34 * NameNode. This counter is supposed to keep track of blocks currently 35 * scheduled to a datanode. 36 */ 37 public class TestBlocksScheduledCounter extends TestCase { 38 testBlocksScheduledCounter()39 public void testBlocksScheduledCounter() throws IOException { 40 41 MiniDFSCluster cluster = new MiniDFSCluster(new Configuration(), 1, 42 true, null); 43 cluster.waitActive(); 44 FileSystem fs = cluster.getFileSystem(); 45 46 //open a file an write a few bytes: 47 FSDataOutputStream out = fs.create(new Path("/testBlockScheduledCounter")); 48 for (int i=0; i<1024; i++) { 49 out.write(i); 50 } 51 // flush to make sure a block is allocated. 52 ((DFSOutputStream)(out.getWrappedStream())).sync(); 53 54 ArrayList<DatanodeDescriptor> dnList = new ArrayList<DatanodeDescriptor>(); 55 cluster.getNameNode().getNamesystem().DFSNodesStatus(dnList, dnList); 56 DatanodeDescriptor dn = dnList.get(0); 57 58 assertEquals(1, dn.getBlocksScheduled()); 59 60 // close the file and the counter should go to zero. 61 out.close(); 62 assertEquals(0, dn.getBlocksScheduled()); 63 } 64 } 65