Getting crawl metrics

Call the CasCrawler.getMetrics() method to return the metrics of a crawl. Metrics can be returned for a running crawl or (if the crawl is not running) for the last complete crawl.

The syntax of the method is: 

CasCrawler.getMetrics(CrawlId crawlId)

The crawlId parameter is a CrawlId object that contains the name of the crawl for which metrics are to be returned.

The method returns a List<Metric> object, which (if not empty) will have one or more Metric objects. A Metric is a key-value pair that holds the value of a particular metric. The keys are the metric's ID (a MetricId enum class). See the CAS Server API Reference (Javadoc) for the list of MetricId enumerations.

The CRAWL_STOP_CAUSE MetricId has one of the following values:

If a crawl fails, the CRAWL_FAILURE_REASON MetricId provides a message from the CAS Server explaining the failure.

Your application can print out all or some of the metric values.

To get the metrics of a crawl:

  1. Make sure that you have created a connection to the CAS Server. (A CasCrawler object named crawler is used in this example.)

  2. Set the name for the crawl by first instantiating a CrawlId object and then setting its Id.

    For example: 

    // Create a new crawl Id with the name set to Demo.
CrawlId crawlId = new CrawlId("Demo");

  3. Call the CasCrawler.getMetrics() method with the crawl ID.

    For example: 

    List<Metric> metricList = crawler.getMetrics(crawlId);

  4. Print the metrics by retrieving the values from the Metric objects. For example, if you want to print the number of records that have been processed so far by a running crawl, the code would be: 

    if (crawler.getStatus(demoCrawlId).getState.equals(CrawlerState.RUNNING)) { 
  List<Metric> metricList = crawler.getMetrics(crawlId);
  for (Metric metric : metricList.getMetric()) {
    MetricId id = metric.getMetricId();
    if (id.equals(MetricId.TOTAL_RECORDS)) {
      System.out.println("Total records: " + metric.getValue());
    }
  }
}

The CasCrawler.getMetrics() method throws a CrawlNotFoundException if the specified crawl (the crawlId parameter) does not exist or is otherwise not found.

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