import org.apache.hadoop.hdfs.server.namenode.FSNamesystem.SafeModeInfo; //导入依赖的package包/类
/**
 * @return the number of blocks marked safe by safemode, or -1
 * if safemode is not running.
 */
public static int getSafeModeSafeBlocks(NameNode nn) {
  SafeModeInfo smi = nn.getNamesystem().getSafeModeInfoForTests();
  if (smi == null) {
    return -1;
  }
  return smi.blockSafe;
}
 

import org.apache.hadoop.hdfs.server.namenode.FSNamesystem.SafeModeInfo; //导入依赖的package包/类
/**
 * @return true if safemode is not running, or if safemode has already
 * initialized the replication queues
 */
public static boolean safeModeInitializedReplQueues(NameNode nn) {
  SafeModeInfo smi = nn.getNamesystem().getSafeModeInfoForTests();
  if (smi == null) {
    return true;
  }
  return smi.initializedReplQueues;
}
 

import org.apache.hadoop.hdfs.server.namenode.FSNamesystem.SafeModeInfo; //导入依赖的package包/类
/**
 * @return the number of blocks marked safe by safemode, or -1
 * if safemode is not running.
 */
public static int getSafeModeSafeBlocks(NameNode nn) throws IOException {
  SafeModeInfo smi = nn.getNamesystem().getSafeModeInfoForTests();
  if (smi == null) {
    return -1;
  }
  return smi.blockSafe();
}
 

import org.apache.hadoop.hdfs.server.namenode.FSNamesystem.SafeModeInfo; //导入依赖的package包/类
/**
 * @return true if safemode is not running, or if safemode has already
 * initialized the replication queues
 */
public static boolean safeModeInitializedReplQueues(NameNode nn) {
  SafeModeInfo smi = nn.getNamesystem().getSafeModeInfoForTests();
  if (smi == null) {
    return true;
  }
  return smi.initializedReplicationQueues;
}
 

import org.apache.hadoop.hdfs.server.namenode.FSNamesystem.SafeModeInfo; //导入依赖的package包/类
/**
 * Make sure the client retries when the active NN is in safemode
 */
@Test (timeout=300000)
public void testClientRetrySafeMode() throws Exception {
  final Map<Path, Boolean> results = Collections
      .synchronizedMap(new HashMap<Path, Boolean>());
  final Path test = new Path("/test");
  // let nn0 enter safemode
  NameNodeAdapter.enterSafeMode(nn0, false);
  SafeModeInfo safeMode = (SafeModeInfo) Whitebox.getInternalState(
      nn0.getNamesystem(), "safeMode");
  Whitebox.setInternalState(safeMode, "extension", Integer.valueOf(30000));
  LOG.info("enter safemode");
  new Thread() {
    @Override
    public void run() {
      try {
        boolean mkdir = fs.mkdirs(test);
        LOG.info("mkdir finished, result is " + mkdir);
        synchronized (TestHASafeMode.this) {
          results.put(test, mkdir);
          TestHASafeMode.this.notifyAll();
        }
      } catch (Exception e) {
        LOG.info("Got Exception while calling mkdir", e);
      }
    }
  }.start();
  
  // make sure the client's call has actually been handled by the active NN
  assertFalse("The directory should not be created while NN in safemode",
      fs.exists(test));
  
  Thread.sleep(1000);
  // let nn0 leave safemode
  NameNodeAdapter.leaveSafeMode(nn0);
  LOG.info("leave safemode");
  
  synchronized (this) {
    while (!results.containsKey(test)) {
      this.wait();
    }
    assertTrue(results.get(test));
  }
}