Implements: ICounters, IReconfigurable, ICounterTimingCallback

Description

The CachedCounters class allows you to create performace counters that measure and store those values in memory.

Important points

• Child classes can implement saving of the counters into various different destinations.

Configuration parameters

options:

• interval: interval in milliseconds to save current counters measurements (default: 5 mins)
• reset_timeout: timeout in milliseconds to reset the counters. 0 disables the reset (default: 0)

Constructors

Creates a new CachedCounters object.

public CachedCounters()

Fields

_interval

Default time interval.

protected final long _interval = 300000

_cache

A dictionary containing the cached values.

protected Map<String, Counter> _cache = new HashMap<>()

_updated

A boolean value that indicates whether the counter has been updated or not.

protected boolean _updated = false

_lastDumpTime

Time of the last dump.

protected long _lastDumpTime = System.currentTimeMillis()

_lastResetTime

Last time when was reset timer

protected long _lastResetTime = System.currentTimeMillis()

_resetTimeout

Timeout to reset timer

protected long _resetTimeout = 0

Instance methods

beginTiming

Begins measurement of execution time interval. It returns CounterTiming object which has to be called at CounterTiming.endTiming to end the measurement and update the counter.

public CounterTiming beginTiming(String name)

• name: String - a counter name of Interval type.
• returns: CounterTiming - a callback object to end timing.

clear

Clears (resets) a counter specified by its name.

public void clear(String name)

• name: string - a counter name to clear.

clearAll

Clears (resets) all counters.

public void clearAll()

configure

Configures component by passing configuration parameters.

public void configure(ConfigParams config)

• config: ConfigParams - configuration parameters to be set.

dump

Dumps (saves) the current values of counters.

public void dump() throws InvocationException

endTiming

Ends measurement of execution elapsed time and updates specified counter.

public void endTiming(String name, float elapsed)

• name: String - a counter name
• elapsed: float - execution elapsed time in milliseconds to update the counter.

get

Gets a counter specified by its name. It counter does not exist or its type doesn’t match the specified type it creates a new one.

public CounterType get(String name, int type)

• name: String - a counter name to retrieve.
• type: int - a counter type.
• returns: Counter - an existing or newly created counter of the specified type.

getAll

Gets all captured counters.

public List<Counter[]> getAll()

• returns: List<Counter[]> - a list with counters.

getInterval

Gets the counters dump/save interval.

public long getInterval()

• returns: long - the interval in milliseconds.

increment

Increments counter by given value.

public void incrementOne(String name)

• name: String - a counter name of Increment type.
• value: number - a value to add to the counter.

incrementOne

Increments counter by 1.

public void incrementOne(String name)

• name: String - a counter name of Increment type.

last

Records the last calculated measurement value. Usually this method is used by metrics calculated externally.

public void last(String name, float value)

• name: String - a counter name of Last type.
• value: float - a last value to record.

setInterval

Sets the counters dump/save interval.

public void setInterval(long value)

• value: long - a new interval in milliseconds.

stats

Calculates min/average/max statistics based on the current and previous values.

public void stats(String name, float value)

• name: String - a counter name of Statistics type
• value: float - a value to update statistics

timestamp

Records the given timestamp.

public void timestamp(String name, ZonedDateTime value

• name: String - a counter name of Timestamp type.
• value: ZonedDateTime - a timestamp to record.

timestampNow

Records the current time as a timestamp.

public void timestampNow(String name)

• name: String - a counter name of Timestamp type.

update

Makes counter measurements as updated and dumps them when timeout expires.

protected void update()

Abstract methods

save

Saves the current counters measurements.

protected abstract void save(List<Counter[]> counters) throws InvocationException

• counters: Counter[] - current counters measurements to be saved.