com.yahoo.bullet.common.metrics

Class MetricCollector

java.lang.Object

com.yahoo.bullet.common.metrics.MetricCollector

public class MetricCollector
extends Object

Utility class to concurrently store frequency and average metrics for various string keys. Averages are computed by storing the absolute totals of each metric along with the counts and the actual average division is computed on extractMetrics(). This method will also reset all the metrics stored. Use this class if you want to count or average metrics periodically and with high concurrency, extract them and report them somewhere.

Constructor Summary

Constructors

Constructor and Description
MetricCollector(List<String> frequencies) A constructor that sets up the collector with an initial count of 0 for each of the given metrics.
MetricCollector(List<String> frequencies, List<String> averages) A constructor that sets up the collector with an initial count of 0 for each of the given metrics.

Method Summary

Modifier and Type	Method and Description
void	add(String key, long total) Add the given total to the existing sum for the given key.
void	average(String key, long absoluteTotal) Increment one instance of an average metric with the absolute total.
void	average(String key, long absoluteTotal, long frequencyTotal) Average the given absolute total and frequency total into the metric so far.
Map<String,Number>	extractMetrics() Gets and resets the metrics currently stored in the collector.
void	increment(String key) Increment the value for the given key.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MetricCollector

public MetricCollector(List<String> frequencies)

A constructor that sets up the collector with an initial count of 0 for each of the given metrics.

Parameters:

frequencies - The List of metrics to initialize to a count of zero.

MetricCollector

public MetricCollector(List<String> frequencies,
                       List<String> averages)

A constructor that sets up the collector with an initial count of 0 for each of the given metrics.

Parameters:

frequencies - The List of frequencies to initialize to a count of zero.

averages - The List of averages to maintain.

Method Detail

increment

public void increment(String key)

Increment the value for the given key. It will be created if it does not exist.

Parameters:

key - The key to increment.

add

public void add(String key,
                long total)

Add the given total to the existing sum for the given key. It will be created if it does not exist.

Parameters:

key - The key to add to.

total - The total to add as.

average

public void average(String key,
                    long absoluteTotal)

Increment one instance of an average metric with the absolute total.

Parameters:

key - The average metric to add the total to.

absoluteTotal - The total to add.

average

public void average(String key,
                    long absoluteTotal,
                    long frequencyTotal)

Average the given absolute total and frequency total into the metric so far.

Parameters:

key - The name of the average metric.

absoluteTotal - The total of the metric being averaged.

frequencyTotal - The total number of instances of the absolute metric provided in this call.

extractMetrics

public Map<String,Number> extractMetrics()

Gets and resets the metrics currently stored in the collector.

Returns:

Map of names to counts of frequencies.