code: public void addVertex(final AbstractJobInputVertex inputVertex) {
  
  		if (!inputVertices.containsKey(inputVertex.getID())) {
  			inputVertices.put(inputVertex.getID(), inputVertex);
  		}
  	}
docs: Adds a new input vertex to the job graph if it is not already included.
  
  @param inputVertex
  the new input vertex to be added