@Override
  public boolean canHandle (TaskExecution aTaskExecution) {
    String parentId = aTaskExecution.getParentId();
    if(parentId!=null) {
      TaskExecution parentExecution = taskExecutionRepo.findOne(parentId);
      return parentExecution.getType().equals(DSL.PARALLEL);
    }
    return false;
  }
<p>A {@link TaskCompletionHandler} implementation which handles completions 
of parallel construct tasks.</p>

<p>This handler keeps track of how many tasks were completed so far and 
when all parallel tasks completed for a given task it will then complete
the overall <code>parallel</code> task.</p> 

@author Arik Cohen
@since May 12, 2017
@see ParallelTaskDispatcher
src/main/java/com/creactiviti/piper/core/task/ParallelTaskCompletionHandler.java