public final synchronized void allocate()

in twill-yarn/src/main/java/org/apache/twill/internal/yarn/AbstractYarnAMClient.java [105:153]
35 lines of code
10 McCabe index (conditional complexity)

  public final synchronized void allocate(float progress, AllocateHandler handler) throws Exception {
    // In one allocate cycle, either only do new container request or removal of requests.
    // This is a workaround for YARN-314.
    // When remove a container request, AMRMClient will send a container request with size = 0
    // With bug YARN-314, if we mix the allocate call with new container request of the same priority,
    // in some cases the RM would not see the new request (based on sorting of resource capability),
    // but rather only see the one with size = 0.
    if (removes.isEmpty()) {
      for (T request : requests) {
        addContainerRequest(request);
      }
      requests.clear();
    } else {
      for (T request : removes) {
        removeContainerRequest(request);
      }
      removes.clear();
    }

    if (!blacklistAdditions.isEmpty() || !blacklistRemovals.isEmpty()) {
      updateBlacklist(blacklistAdditions, blacklistRemovals);
      blacklistAdditions.clear();
      blacklistRemovals.clear();
    }

    AllocateResult allocateResponse = doAllocate(progress);
    List<RunnableProcessLauncher> launchers = allocateResponse.getLaunchers();

    if (!launchers.isEmpty()) {
      handler.acquired(launchers);

      // If no process has been launched through the given launcher, return the container.
      for (ProcessLauncher<YarnContainerInfo> l : launchers) {
        // This cast always works.
        RunnableProcessLauncher launcher = (RunnableProcessLauncher) l;
        if (!launcher.isLaunched()) {
          YarnContainerInfo containerInfo = launcher.getContainerInfo();
          // Casting is needed in Java 8, otherwise it complains about ambiguous method over the info(String, Throwable)
          LOG.info("Nothing to run in container, releasing it: {}", (Object) containerInfo.getContainer());
          releaseAssignedContainer(containerInfo);
        }
      }
    }

    List<YarnContainerStatus> completed = allocateResponse.getCompletedStatus();
    if (!completed.isEmpty()) {
      handler.completed(completed);
    }
  }