How to use

chooseTarget

method

in

org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault

private enum NodeNotChosenReason {
 NOT_IN_SERVICE("the node is not in service"),
 NODE_STALE("the node is stale"),
 NODE_TOO_BUSY("the node is too busy"),
 TOO_MANY_NODES_ON_RACK("the rack has too many chosen nodes"),
 NOT_ENOUGH_STORAGE_SPACE("not enough storage space to place the block");
 private final String text;
 NodeNotChosenReason(final String logText) {
  text = logText;
 }
 private String getText() {
  return text;
 }
}

if (favoredNodes == null || favoredNodes.size() == 0) {
 return chooseTarget(src, numOfReplicas, writer,
   new ArrayList<DatanodeStorageInfo>(numOfReplicas), false, 
   excludedNodes, blocksize, storagePolicy, flags);
   chooseTarget(src, numOfReplicas, writer,
     new ArrayList<DatanodeStorageInfo>(numOfReplicas), false,
     favoriteAndExcludedNodes, blocksize, storagePolicy, flags);
return chooseTarget(src, numOfReplicas, writer, 
  new ArrayList<DatanodeStorageInfo>(numOfReplicas), false, 
  excludedNodes, blocksize, storagePolicy, flags);

 excludedNodeCopy.add(writer);
localNode = chooseTarget(numOfReplicas, writer,
  excludedNodeCopy, blocksize, maxNodesPerRack, results,
  avoidStaleNodes, storagePolicy,
localNode = chooseTarget(numOfReplicas, writer, excludedNodes,
  blocksize, maxNodesPerRack, results, avoidStaleNodes,
  storagePolicy, EnumSet.noneOf(StorageType.class), results.isEmpty());

 @Override
 public DatanodeStorageInfo[] chooseTarget(String srcPath,
                  int numOfReplicas,
                  Node writer,
                  List<DatanodeStorageInfo> chosenNodes,
                  boolean returnChosenNodes,
                  Set<Node> excludedNodes,
                  long blocksize,
                  final BlockStoragePolicy storagePolicy) {
  DatanodeStorageInfo[] results = super.chooseTarget(srcPath,
    numOfReplicas, writer, chosenNodes, returnChosenNodes, excludedNodes,
    blocksize, storagePolicy);
  try {
   Thread.sleep(3000);
  } catch (InterruptedException e) {}
  return results;
 }
}

if (favoredNodes == null || favoredNodes.size() == 0) {
 return chooseTarget(src, numOfReplicas, writer,
   new ArrayList<DatanodeStorageInfo>(numOfReplicas), false, 
   excludedNodes, blocksize, storagePolicy);
   chooseTarget(src, numOfReplicas, writer, results,
     false, favoriteAndExcludedNodes, blocksize, storagePolicy);
 for (int i = 0; i < remainingTargets.length; i++) {
return chooseTarget(src, numOfReplicas, writer, 
  new ArrayList<DatanodeStorageInfo>(numOfReplicas), false, 
  excludedNodes, blocksize, storagePolicy);

final Node localNode = chooseTarget(numOfReplicas, writer, excludedNodes,
  blocksize, maxNodesPerRack, results, avoidStaleNodes, storagePolicy,
  EnumSet.noneOf(StorageType.class), results.isEmpty());

if (favoredNodes == null || favoredNodes.size() == 0) {
 return chooseTarget(src, numOfReplicas, writer,
   new ArrayList<DatanodeStorageInfo>(numOfReplicas), false, 
   excludedNodes, blocksize, storagePolicy);
   chooseTarget(src, numOfReplicas, writer, results,
     false, favoriteAndExcludedNodes, blocksize, storagePolicy);
 for (int i = 0; i < remainingTargets.length; i++) {
return chooseTarget(src, numOfReplicas, writer, 
  new ArrayList<DatanodeStorageInfo>(numOfReplicas), false, 
  excludedNodes, blocksize, storagePolicy);

final Node localNode = chooseTarget(numOfReplicas, writer, excludedNodes,
  blocksize, maxNodesPerRack, results, avoidStaleNodes, storagePolicy,
  EnumSet.noneOf(StorageType.class), results.isEmpty());

return chooseTarget(numOfReplicas, writer, oldExcludedNodes, blocksize,
  maxNodesPerRack, results, false, storagePolicy, unavailableStorages,
  newBlock);
return chooseTarget(numOfReplicas, writer, oldExcludedNodes, blocksize,
  maxNodesPerRack, results, false, storagePolicy, unavailableStorages,
  newBlock);

targets = repl.chooseTarget(filename, 4, dataNodes[0], chosenNodes, false, 
  excludedNodes, BLOCK_SIZE, TestBlockStoragePolicy.DEFAULT_STORAGE_POLICY);
assertEquals(targets.length, 4);
excludedNodes.add(dataNodes[1]); 
chosenNodes.add(storages[2]);
targets = repl.chooseTarget(filename, 1, dataNodes[0], chosenNodes, true,
  excludedNodes, BLOCK_SIZE, TestBlockStoragePolicy.DEFAULT_STORAGE_POLICY);
System.out.println("targets=" + Arrays.asList(targets));

return chooseTarget(numOfReplicas, writer, oldExcludedNodes, blocksize,
  maxNodesPerRack, results, false, storagePolicy, unavailableStorages,
  newBlock);
return chooseTarget(numOfReplicas, writer, oldExcludedNodes, blocksize,
  maxNodesPerRack, results, false, storagePolicy, unavailableStorages,
  newBlock);