/**
* 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;
import static org.junit.Assert.assertEquals;
import java.io.IOException;
import java.util.ArrayList;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor;
import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeManager;
import org.junit.Test;
/**
* This class tests DatanodeDescriptor.getBlocksScheduled() at the
* NameNode. This counter is supposed to keep track of blocks currently
* scheduled to a datanode.
*/
public class TestBlocksScheduledCounter {
@Test
public void testBlocksScheduledCounter() throws IOException {
MiniDFSCluster cluster = new MiniDFSCluster.Builder(new HdfsConfiguration())
.build();
cluster.waitActive();
FileSystem fs = cluster.getFileSystem();
//open a file an write a few bytes:
FSDataOutputStream out = fs.create(new Path("/testBlockScheduledCounter"));
for (int i=0; i<1024; i++) {
out.write(i);
}
// flush to make sure a block is allocated.
out.hflush();
ArrayList<DatanodeDescriptor> dnList = new ArrayList<DatanodeDescriptor>();
final DatanodeManager dm = cluster.getNamesystem().getBlockManager(
).getDatanodeManager();
dm.fetchDatanodes(dnList, dnList, false);
DatanodeDescriptor dn = dnList.get(0);
assertEquals(1, dn.getBlocksScheduled());
// close the file and the counter should go to zero.
out.close();
assertEquals(0, dn.getBlocksScheduled());
}
}