import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor.CachedBlocksList.Type; //导入依赖的package包/类
public void setCachedLocations(LocatedBlock block) {
  CachedBlock cachedBlock =
      new CachedBlock(block.getBlock().getBlockId(),
          (short)0, false);
  cachedBlock = cachedBlocks.get(cachedBlock);
  if (cachedBlock == null) {
    return;
  }
  List<DatanodeDescriptor> datanodes = cachedBlock.getDatanodes(Type.CACHED);
  for (DatanodeDescriptor datanode : datanodes) {
    block.addCachedLoc(datanode);
  }
}
 

import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor.CachedBlocksList.Type; //导入依赖的package包/类
public void setCachedLocations(LocatedBlock block) {
  CachedBlock cachedBlock =
      new CachedBlock(block.getBlock().getBlockId(),
          (short)0, false);
  cachedBlock = cachedBlocks.get(cachedBlock);
  if (cachedBlock == null) {
    return;
  }
  List<DatanodeDescriptor> cachedDNs = cachedBlock.getDatanodes(Type.CACHED);
  for (DatanodeDescriptor datanode : cachedDNs) {
    // Filter out cached blocks that do not have a backing replica.
    //
    // This should not happen since it means the CacheManager thinks
    // something is cached that does not exist, but it's a safety
    // measure.
    boolean found = false;
    for (DatanodeInfo loc : block.getLocations()) {
      if (loc.equals(datanode)) {
        block.addCachedLoc(loc);
        found = true;
        break;
      }
    }
    if (!found) {
      LOG.warn("Datanode {} is not a valid cache location for block {} "
          + "because that node does not have a backing replica!",
          datanode, block.getBlock().getBlockName());
    }
  }
}
 

import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor.CachedBlocksList.Type; //导入依赖的package包/类
/**
 * Wait for the NameNode to have an expected number of cached blocks
 * and replicas.
 * @param nn NameNode
 * @param expectedCachedBlocks if -1, treat as wildcard
 * @param expectedCachedReplicas if -1, treat as wildcard
 * @throws Exception
 */
private static void waitForCachedBlocks(NameNode nn,
    final int expectedCachedBlocks, final int expectedCachedReplicas,
    final String logString) throws Exception {
  final FSNamesystem namesystem = nn.getNamesystem();
  final CacheManager cacheManager = namesystem.getCacheManager();
  LOG.info("Waiting for " + expectedCachedBlocks + " blocks with " +
           expectedCachedReplicas + " replicas.");
  GenericTestUtils.waitFor(new Supplier<Boolean>() {
    @Override
    public Boolean get() {
      int numCachedBlocks = 0, numCachedReplicas = 0;
      namesystem.readLock();
      try {
        GSet<CachedBlock, CachedBlock> cachedBlocks =
            cacheManager.getCachedBlocks();
        if (cachedBlocks != null) {
          for (Iterator<CachedBlock> iter = cachedBlocks.iterator();
              iter.hasNext(); ) {
            CachedBlock cachedBlock = iter.next();
            numCachedBlocks++;
            numCachedReplicas += cachedBlock.getDatanodes(Type.CACHED).size();
          }
        }
      } finally {
        namesystem.readUnlock();
      }

      LOG.info(logString + " cached blocks: have " + numCachedBlocks +
          " / " + expectedCachedBlocks + ".  " +
          "cached replicas: have " + numCachedReplicas +
          " / " + expectedCachedReplicas);

      if (expectedCachedBlocks == -1 ||
          numCachedBlocks == expectedCachedBlocks) {
        if (expectedCachedReplicas == -1 ||
            numCachedReplicas == expectedCachedReplicas) {
          return true;
        }
      }
      return false;
    }
  }, 500, 60000);
}
 

import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor.CachedBlocksList.Type; //导入依赖的package包/类
/**
 * Wait for the NameNode to have an expected number of cached blocks
 * and replicas.
 * @param nn NameNode
 * @param expectedCachedBlocks if -1, treat as wildcard
 * @param expectedCachedReplicas if -1, treat as wildcard
 * @throws Exception
 */
private static void waitForCachedBlocks(NameNode nn,
    final int expectedCachedBlocks, final int expectedCachedReplicas,
    final String logString) throws Exception {
  final FSNamesystem namesystem = nn.getNamesystem();
  final CacheManager cacheManager = namesystem.getCacheManager();
  LOG.info("Waiting for " + expectedCachedBlocks + " blocks with " +
           expectedCachedReplicas + " replicas.");
  GenericTestUtils.waitFor(new Supplier<Boolean>() {
    @Override
    public Boolean get() {
      int numCachedBlocks = 0, numCachedReplicas = 0;
      namesystem.readLock();
      try {
        GSet<CachedBlock, CachedBlock> cachedBlocks =
            cacheManager.getCachedBlocks();
        if (cachedBlocks != null) {
          for (Iterator<CachedBlock> iter = cachedBlocks.iterator();
              iter.hasNext(); ) {
            CachedBlock cachedBlock = iter.next();
            numCachedBlocks++;
            numCachedReplicas += cachedBlock.getDatanodes(Type.CACHED).size();
          }
        }
      } finally {
        namesystem.readUnlock();
      }
      if (expectedCachedBlocks == -1 ||
          numCachedBlocks == expectedCachedBlocks) {
        if (expectedCachedReplicas == -1 ||
            numCachedReplicas == expectedCachedReplicas) {
          return true;
        }
      }
      LOG.info(logString + " cached blocks: have " + numCachedBlocks +
          " / " + expectedCachedBlocks + ".  " +
          "cached replicas: have " + numCachedReplicas +
          " / " + expectedCachedReplicas);
      return false;
    }
  }, 500, 60000);
}
 

import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor.CachedBlocksList.Type; //导入依赖的package包/类
/**
 * Get a list of the datanodes which this block is cached,
 * planned to be cached, or planned to be uncached on.
 *
 * @param type      If null, this parameter is ignored.
 *                  If it is non-null, we match only datanodes which
 *                  have it on this list.
 *                  See {@link DatanodeDescriptor.CachedBlocksList.Type}
 *                  for a description of all the lists.
 *                  
 * @return          The list of datanodes.  Modifying this list does not
 *                  alter the state of the CachedBlock.
 */
public List<DatanodeDescriptor> getDatanodes(Type type) {
  List<DatanodeDescriptor> nodes = new LinkedList<DatanodeDescriptor>();
  for (int i = 0; i < triplets.length; i += 3) {
    CachedBlocksList list = (CachedBlocksList)triplets[i];
    if ((type == null) || (list.getType() == type)) {
      nodes.add(list.getDatanode());
    }
  }
  return nodes;
}
 

import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeDescriptor.CachedBlocksList.Type; //导入依赖的package包/类
/**
 * Get a list of the datanodes which this block is cached,
 * planned to be cached, or planned to be uncached on.
 *
 * @param type      If null, this parameter is ignored.
 *                  If it is non-null, we match only datanodes which
 *                  have it on this list.
 *                  See {@link DatanodeDescriptor#CachedBlocksList#Type}
 *                  for a description of all the lists.
 *                  
 * @return          The list of datanodes.  Modifying this list does not
 *                  alter the state of the CachedBlock.
 */
public List<DatanodeDescriptor> getDatanodes(Type type) {
  List<DatanodeDescriptor> nodes = new LinkedList<DatanodeDescriptor>();
  for (int i = 0; i < triplets.length; i += 3) {
    CachedBlocksList list = (CachedBlocksList)triplets[i];
    if ((type == null) || (list.getType() == type)) {
      nodes.add(list.getDatanode());
    }
  }
  return nodes;
}