Method tsuidFromMetric

src/meta/TSUIDQuery.java:475–523

Converts the given metric and tags to a TSUID by resolving the strings to their UIDs. Note that the resulting TSUID may not exist if the combination was not written to TSDB @param tsdb The TSDB to use for storage access @param metric The metric name to resolve @param tags The tags to resolve. May no

(final TSDB tsdb, 
      final String metric, final Map<String, String> tags)

   * empty.
   */
  public static Deferred<byte[]> tsuidFromMetric(final TSDB tsdb, 
      final String metric, final Map<String, String> tags) {
    if (metric == null || metric.isEmpty()) {
      throw new IllegalArgumentException("The metric cannot be empty");
    }
    if (tags == null || tags.isEmpty()) {
      throw new IllegalArgumentException("Tags cannot be null or empty "
          + "when getting a TSUID");
    }
    
    final byte[] metric_uid = new byte[TSDB.metrics_width()];
    
    class TagsCB implements Callback<byte[], ArrayList<byte[]>> {
      @Override
      public byte[] call(final ArrayList<byte[]> tag_list) throws Exception {
        final byte[] tsuid = new byte[metric_uid.length + 
                                      ((TSDB.tagk_width() + TSDB.tagv_width()) 
                                          * tag_list.size())];
        int idx = 0;
        System.arraycopy(metric_uid, 0, tsuid, 0, metric_uid.length);
        idx += metric_uid.length;
        for (final byte[] t : tag_list) {
          System.arraycopy(t, 0, tsuid, idx, t.length);
          idx += t.length;
        }
        return tsuid;
      }
      @Override
      public String toString() {
        return "Tag resolution callback";
      }
    }
    
    class MetricCB implements Callback<Deferred<byte[]>, byte[]> {
      @Override
      public Deferred<byte[]> call(final byte[] uid) 
          throws Exception {
        System.arraycopy(uid, 0, metric_uid, 0, uid.length);
        return Tags.resolveAllAsync(tsdb, tags).addCallback(new TagsCB());
      }
      @Override
      public String toString() {
        return "Metric resolution callback";
      }
    }
    
    return tsdb.getUIDAsync(UniqueIdType.METRIC, metric)
        .addCallbackDeferring(new MetricCB());
  }

  /**
   * Attempts to retrieve the last data point for the given TSUID.