Method compile

src/query/expression/ExpressionIterator.java:237–302

Builds the iterator by computing the intersection of all series in all sets and sets up the output. @throws IllegalArgumentException if there aren't any results, or we don't have a result for each variable, or something else is wrong. @throws IllegalDataException if no series were left after computi

()

   * intersection.
   */
  public void compile() {
    if (LOG.isDebugEnabled()) {
      LOG.debug("Compiling " + this);
    }
    if (results.size() < 1) {
      throw new IllegalArgumentException("No results for any variables in "
          + "the expression: " + this);
    }
    if (results.size() < names.size()) {
      throw new IllegalArgumentException("Not enough query results [" 
          + results.size() + " total results found] for the expression variables [" 
          + names.size() + " expected] " + this);
    }
    
    // don't care if we have extra results, but we had darned well better make
    // sure we have a result set for each variable    
    for (final String variable : names) {
      // validation
      final ITimeSyncedIterator it = results.get(variable.toLowerCase());
      if (it == null) {
        throw new IllegalArgumentException("Missing results for variable " + variable);
      }

      if (it instanceof ExpressionIterator) {
        ((ExpressionIterator)it).compile();
      }
      if (LOG.isDebugEnabled()) {
        LOG.debug("Matched variable " + variable + " to " + it);
      }
    }
    
    // TODO implement other set functions
    switch (set_operator) {
    case INTERSECTION:
      iterator = new IntersectionIterator(id, results, intersect_on_query_tagks, 
          include_agg_tags);
      break;
    case UNION:
      iterator = new UnionIterator(id, results, intersect_on_query_tagks, 
          include_agg_tags);
    }
    iteration_results = iterator.getResults();
    
    dps = new ExpressionDataPoint[iterator.getSeriesSize()];
    for (int i = 0; i < iterator.getSeriesSize(); i++) {
      final Iterator<Entry<String, ExpressionDataPoint[]>> it = 
          iteration_results.entrySet().iterator();
      Entry<String, ExpressionDataPoint[]> entry = it.next();
      
      if (entry.getValue() == null || entry.getValue()[i] == null) {
        dps[i] = new ExpressionDataPoint();
      } else {
        dps[i] = new ExpressionDataPoint(entry.getValue()[i]);
      }
      while (it.hasNext()) {
        entry = it.next();
        if (entry.getValue() != null && entry.getValue()[i] != null) {
          dps[i].add(entry.getValue()[i]);