public Map<String, Rxn> getReactions(String compartment) {
   TreeMap<String, Rxn> crxns = new TreeMap<String, Rxn>();
   for (String rn : reactions.keySet()) {
     Rxn r = reactions.get(rn);
     if (r.getLocation().equals(compartment)) {
       crxns.put(rn, r);
     }
   }
   return crxns;
 }
 public Set<String> getOutputReactions(Rxn r) {
   TreeSet<String> rxns = new TreeSet<String>();
   for (String rn : reactions.keySet()) {
     Rxn rxn = reactions.get(rn);
     if (r.connects(rxn)) {
       rxns.add(rn);
     }
   }
   return rxns;
 }
 public Rxn getReaction(String rxnAbbrev) {
   return reactions.get(rxnAbbrev);
 }
 public LogicalORFTree getLogicalORFTree(String rxnAbbrev) {
   return orfSets.get(rxnAbbrev);
 }