code: public Map<Namespace, String> equivalence(SkinnyUUID sourceUUID)
              throws EquivalencerException {
          if (sourceUUID == null) {
              throw new InvalidArgument("sourceUUID", sourceUUID);
          }
  
          loadEquivalencingEngine();
  
          try {
              final List<Parameter> equivalences = this.paramEquivalencer
                      .findEquivalences(sourceUUID);
              Map<Namespace, String> equivalenceMap = sizedHashMap(equivalences
                      .size());
  
              for (final Parameter equivalence : equivalences) {
                  equivalenceMap.put(equivalence.getNamespace(),
                          equivalence.getValue());
              }
  
              return equivalenceMap;
          } catch (InvalidArgument e) {
              //TODO change exception when paramEquivalencer is changed
              return null;
          } catch (Exception e) {
              final String fmt = "Unable to find equivalences for '%s'";
              final String msg = format(fmt, sourceUUID.toString());
              throw new EquivalencerException(msg, e);
          }
      }
docs: Finds all parameters equivalent to the <tt>sourceParameter</tt>.
  <p>
  Note: The first time any method in {@link Equivalencer} is called the
  equivalencing engine is instantiated, but only once. The equivalencing
  engine loads the BEL equivalence files associated with the framework and
  uses them do perform equivalencing.
  </p>
  
  @param sourceUUID
  @return the equivalent parameters or an empty map if no equivalent
  parameter is found
  @throws EquivalencerException Thrown if an exception occurs finding all
  equivalences