private boolean handleSetInstances()

in twill-yarn/src/main/java/org/apache/twill/internal/appmaster/ApplicationMasterService.java [715:744]

• 24 lines of code
• 9 McCabe index (conditional complexity)

  private boolean handleSetInstances(final Message message, final Runnable completion) {
    if (message.getType() != Message.Type.SYSTEM || message.getScope() != Message.Scope.RUNNABLE) {
      return false;
    }

    Command command = message.getCommand();
    Map<String, String> options = command.getOptions();
    if (!"instances".equals(command.getCommand()) || !options.containsKey("count")) {
      return false;
    }

    final String runnableName = message.getRunnableName();
    if (runnableName == null || runnableName.isEmpty() || !twillSpec.getRunnables().containsKey(runnableName)) {
      LOG.info("Unknown runnable {}", runnableName);
      return false;
    }

    final int newCount = Integer.parseInt(options.get("count"));
    final int oldCount = expectedContainers.getExpected(runnableName);

    LOG.info("Received change instances request for {}, from {} to {}.", runnableName, oldCount, newCount);

    if (newCount == oldCount) {   // Nothing to do, simply complete the request.
      completion.run();
      return true;
    }

    instanceChangeExecutor.execute(createSetInstanceRunnable(message, completion, oldCount, newCount));
    return true;
  }