import org.apache.hadoop.fs.FSDataOutputStream; //導入方法依賴的package包/類

/**

* Test that the reorder algo works as we expect.

*/

@Test

public void testBlockLocation() throws Exception {

// We need to start HBase to get HConstants.HBASE_DIR set in conf

htu.startMiniZKCluster();

MiniHBaseCluster hbm = htu.startMiniHBaseCluster(1, 1);

conf = hbm.getConfiguration();

// The "/" is mandatory, without it we've got a null pointer exception on the namenode

final String fileName = "/helloWorld";

Path p = new Path(fileName);

final int repCount = 3;

Assert.assertTrue((short) cluster.getDataNodes().size() >= repCount);

// Let's write the file

FSDataOutputStream fop = dfs.create(p, (short) repCount);

final double toWrite = 875.5613;

fop.writeDouble(toWrite);

fop.close();

for (int i=0; i<10; i++){

// The interceptor is not set in this test, so we get the raw list at this point

LocatedBlocks l;

final long max = System.currentTimeMillis() + 10000;

do {

l = getNamenode(dfs.getClient()).getBlockLocations(fileName, 0, 1);

Assert.assertNotNull(l.getLocatedBlocks());

Assert.assertEquals(l.getLocatedBlocks().size(), 1);

Assert.assertTrue("Expecting " + repCount + " , got " + l.get(0).getLocations().length,

System.currentTimeMillis() < max);

} while (l.get(0).getLocations().length != repCount);

// Should be filtered, the name is different => The order won't change

Object originalList[] = l.getLocatedBlocks().toArray();

HFileSystem.ReorderWALBlocks lrb = new HFileSystem.ReorderWALBlocks();

lrb.reorderBlocks(conf, l, fileName);

Assert.assertArrayEquals(originalList, l.getLocatedBlocks().toArray());

// Should be reordered, as we pretend to be a file name with a compliant stuff

Assert.assertNotNull(conf.get(HConstants.HBASE_DIR));

Assert.assertFalse(conf.get(HConstants.HBASE_DIR).isEmpty());

String pseudoLogFile = conf.get(HConstants.HBASE_DIR) + "/" +

HConstants.HREGION_LOGDIR_NAME + "/" + host1 + ",6977,6576" + "/mylogfile";

// Check that it will be possible to extract a ServerName from our construction

Assert.assertNotNull("log= " + pseudoLogFile,

DefaultWALProvider.getServerNameFromWALDirectoryName(dfs.getConf(), pseudoLogFile));

// And check we're doing the right reorder.

lrb.reorderBlocks(conf, l, pseudoLogFile);

Assert.assertEquals(host1, l.get(0).getLocations()[2].getHostName());

// Check again, it should remain the same.

lrb.reorderBlocks(conf, l, pseudoLogFile);

Assert.assertEquals(host1, l.get(0).getLocations()[2].getHostName());

}

}