public boolean isRunnable() {
    boolean isrunnable = true;
    if (parentTasks != null) {
      for (Task<?> parent : parentTasks) {
        if (!parent.done()) {
          isrunnable = false;
          break;
        }
      }
    }
    return isrunnable;
  }
Remove the dependent task.

@param dependent
         the task to remove
ql/src/java/org/apache/hadoop/hive/ql/exec/Task.java