private StringBuffer checkDifferences( StringBuffer errors, String prefix, URI leftURI, URI rightURI, Collection<EcoreDifference> differences) { if (differences.size() > 0) { if (errors == null) errors = new StringBuffer(); else errors.append("\n "); errors.append(differences.size() + prefix + "model differences between\n "); errors.append(leftURI); errors.append("\n "); errors.append(rightURI); for (EcoreDifference difference : differences) { errors.append("\n"); errors.append(difference.toString()); } } return errors; }