Method dumpToFiles

src/graph/Plot.java:203–256

Generates the Gnuplot script and data files. @param basepath The base path to use. A number of new files will be created and their names will all start with this string. @return The number of data points sent to Gnuplot. This can be less than the number of data points involved in the query due to

(final String basepath)

   * @throws IOException if there was an error while writing one of the files.
   */
  public int dumpToFiles(final String basepath) throws IOException {
    int npoints = 0;
    final int nseries = datapoints.size();
    final String datafiles[] = nseries > 0 ? new String[nseries] : null;
    FileSystem.checkDirectory(new File(basepath).getParent(),
        Const.MUST_BE_WRITEABLE, Const.CREATE_IF_NEEDED);
    for (int i = 0; i < nseries; i++) {
      datafiles[i] = basepath + "_" + i + ".dat";
      final PrintWriter datafile = new PrintWriter(datafiles[i]);
      try {
        for (final DataPoint d : datapoints.get(i)) {
          final long ts = d.timestamp() / 1000;          
          if (d.isInteger()) {
            datafile.print(ts + utc_offset);
            datafile.print(' ');
            datafile.print(d.longValue());
          } else {
            final double value = d.doubleValue();

            if (Double.isInfinite(value)) {
              // Infinity is invalid.
              throw new IllegalStateException("Infinity found in"
                  + " datapoints #" + i + ": " + value + " d=" + d);
            } else if (Double.isNaN(value)) {
              // NaNs should be skipped.
              continue;
            }

            datafile.print(ts + utc_offset);
            datafile.print(' ');
            datafile.print(value);
          }
          
          datafile.print('\n');
          
          if (ts >= (start_time & UNSIGNED) && ts <= (end_time & UNSIGNED)) {
            npoints++;
          }
        }
      } finally {
        datafile.close();
      }
    }

    if (npoints == 0) {
      // Gnuplot doesn't like empty graphs when xrange and yrange aren't
      // entirely defined, because it can't decide on good ranges with no
      // data.  We always set the xrange, but the yrange is supplied by the
      // user.  Let's make sure it defines a min and a max.
      params.put("yrange", "[0:10]");  // Doesn't matter what values we use.
    }
    writeGnuplotScript(basepath, datafiles);
    return npoints;
  }

  /**
   * Generates the Gnuplot script.