code: private void readRelation(Relationship relation)
     {
        Task predecessor = m_activityMap.get(relation.getPredecessor());
        Task successor = m_activityMap.get(relation.getSuccessor());
        if (predecessor != null && successor != null)
        {
           Duration lag = relation.getLag();
           RelationType type = relation.getType();
           successor.addPredecessor(predecessor, type, lag);
        }
     }
docs: Read an individual Phoenix task relationship.
  
  @param relation Phoenix task relationship