Class MovingAverage

src/query/expression/MovingAverage.java:37–345

Implements a moving average function windowed on either the number of data points or a unit of time. @since 2.3

 * @since 2.3
 */
public class MovingAverage implements Expression {
  
  @Override
  public DataPoints[] evaluate(final TSQuery data_query, 
      final List<DataPoints[]> query_results, final List<String> params) {
    if (data_query == null) {
      throw new IllegalArgumentException("Missing time series query");
    }
    if (query_results == null || query_results.isEmpty()) {
      return new DataPoints[]{};
    }
    if (params == null || params.isEmpty()) {
      throw new IllegalArgumentException("Missing moving average window size");
    }

    String param = params.get(0);
    if (param == null || param.isEmpty()) {
      throw new IllegalArgumentException("Missing moving average window size");
    }
    param = param.trim();
    
    long condition = -1;
    boolean is_time_unit = false;
    if (param.matches("^[0-9]+$")) {
      try {
        condition = Integer.parseInt(param);
      } catch (NumberFormatException nfe) {
        throw new IllegalArgumentException(
            "Invalid parameter, must be an integer", nfe);
      }
    } else if (param.startsWith("'") && param.endsWith("'")) {
      condition = parseParam(param);
      is_time_unit = true;
    } else {
      throw new IllegalArgumentException("Unparseable window size: " + param);
    }
    if (condition <= 0) {
      throw new IllegalArgumentException("Moving average window must be an "
          + "integer greater than zero");
    }

    int num_results = 0;
    for (final DataPoints[] results : query_results) {
      num_results += results.length;
    }
    
    final PostAggregatedDataPoints[] post_agg_results = 
        new PostAggregatedDataPoints[num_results];
    int ix = 0;
    // one or more queries (m=...&m=...&m=...)
    for (final DataPoints[] sub_query_result : query_results) {
      // group bys (m=sum:foo{host=*})
      for (final DataPoints dps: sub_query_result) {
        // TODO(cl) - Avoid iterating and copying if we can help it. We should
        // be able to pass the original DataPoints object to the seekable view
        // and then iterate through it.
        final List<DataPoint> mutable_points = new ArrayList<DataPoint>();
        for (final DataPoint point: dps) {