OneRRule r = newRule((Attribute) enum.nextElement(), data);
try { OneRRule r = newRule((Attribute) enum.nextElement(), data);
  public void buildClassifier(Instances instances)     throws Exception {        boolean noRule = true;    if (instances.checkForStringAttributes()) {      throw new Exception("Can't handle string attributes!");    }    if (instances.classAttribute().isNumeric()) {      throw new Exception("Can't handle numeric class!");    }    Instances data = new Instances(instances);    // new dataset without missing class values    data.deleteWithMissingClass();    if (data.numInstances() == 0) {      throw new Exception("No instances with a class value!");    }    // for each attribute ...    Enumeration enum = instances.enumerateAttributes();    while (enum.hasMoreElements()) {      OneRRule r = newRule((Attribute) enum.nextElement(), data);      // if this attribute is the best so far, replace the rule      if (noRule || r.m_correct > m_rule.m_correct) {	m_rule = r;      }      noRule = false;    }