Recorder (HdrHistogram 2.1.12-SNAPSHOT API)

java.lang.Object
- org.HdrHistogram.Recorder

All Implemented Interfaces:

ValueRecorder
```
public class Recorder
extends Object
implements ValueRecorder
```
Records integer values, and provides stable interval Histogram samples from live recorded data without interrupting or stalling active recording of values. Each interval histogram provided contains all value counts accumulated since the previous interval histogram was taken.
This pattern is commonly used in logging interval histogram information while recording is ongoing.
Recorder supports concurrent recordValue(long) or recordValueWithExpectedInterval(long, long) calls. Recording calls are wait-free on architectures that support atomic increment operations, and are lock-free on architectures that do not.
A common pattern for using a Recorder looks like this:
```
 Recorder recorder = new Recorder(2); // Two decimal point accuracy
 Histogram intervalHistogram = null;
 ...
 [start of some loop construct that periodically wants to grab an interval histogram]
   ...
   // Get interval histogram, recycling previous interval histogram:
   intervalHistogram = recorder.getIntervalHistogram(intervalHistogram);
   histogramLogWriter.outputIntervalHistogram(intervalHistogram);
   ...
 [end of loop construct]
 
```

Constructor Summary

Constructors
Constructor	Description
`Recorder(int numberOfSignificantValueDigits)`	Construct an auto-resizing `Recorder` with a lowest discernible value of 1 and an auto-adjusting highestTrackableValue.
`Recorder(long highestTrackableValue, int numberOfSignificantValueDigits)`	Construct a `Recorder` given the highest value to be tracked and a number of significant decimal digits.
`Recorder(long lowestDiscernibleValue, long highestTrackableValue, int numberOfSignificantValueDigits)`	Construct a `Recorder` given the Lowest and highest values to be tracked and a number of significant decimal digits.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`Histogram`	`getIntervalHistogram()`	Get a new instance of an interval histogram, which will include a stable, consistent view of all value counts accumulated since the last interval histogram was taken.
`Histogram`	`getIntervalHistogram(Histogram histogramToRecycle)`	Get an interval histogram, which will include a stable, consistent view of all value counts accumulated since the last interval histogram was taken.
`Histogram`	`getIntervalHistogram(Histogram histogramToRecycle, boolean enforeContainingInstance)`	Get an interval histogram, which will include a stable, consistent view of all value counts accumulated since the last interval histogram was taken.
`void`	`getIntervalHistogramInto(Histogram targetHistogram)`	Place a copy of the value counts accumulated since accumulated (since the last interval histogram was taken) into `targetHistogram`.
`void`	`recordValue(long value)`	Record a value
`void`	`recordValueWithCount(long value, long count)`	Record a value in the histogram (adding to the value's current count)
`void`	`recordValueWithExpectedInterval(long value, long expectedIntervalBetweenValueSamples)`	Record a value
`void`	`reset()`	Reset any value counts accumulated thus far.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - Recorder
```
public Recorder(int numberOfSignificantValueDigits)
```
    Construct an auto-resizing Recorder with a lowest discernible value of 1 and an auto-adjusting highestTrackableValue. Can auto-resize up to track values up to (Long.MAX_VALUE / 2).
    
    Parameters:
    
    numberOfSignificantValueDigits - Specifies the precision to use. This is the number of significant decimal digits to which the histogram will maintain value resolution and separation. Must be a non-negative integer between 0 and 5.
  - Recorder
```
public Recorder(long highestTrackableValue,
                int numberOfSignificantValueDigits)
```
    Construct a Recorder given the highest value to be tracked and a number of significant decimal digits. The histogram will be constructed to implicitly track (distinguish from 0) values as low as 1.
    
    Parameters:
    
    highestTrackableValue - The highest value to be tracked by the histogram. Must be a positive integer that is >= 2.
    
    numberOfSignificantValueDigits - Specifies the precision to use. This is the number of significant decimal digits to which the histogram will maintain value resolution and separation. Must be a non-negative integer between 0 and 5.
  - Recorder
```
public Recorder(long lowestDiscernibleValue,
                long highestTrackableValue,
                int numberOfSignificantValueDigits)
```
    Construct a Recorder given the Lowest and highest values to be tracked and a number of significant decimal digits. Providing a lowestDiscernibleValue is useful is situations where the units used for the histogram's values are much smaller that the minimal accuracy required. E.g. when tracking time values stated in nanosecond units, where the minimal accuracy required is a microsecond, the proper value for lowestDiscernibleValue would be 1000.
    
    Parameters:
    
    lowestDiscernibleValue - The lowest value that can be tracked (distinguished from 0) by the histogram. Must be a positive integer that is >= 1. May be internally rounded down to nearest power of 2.
    
    highestTrackableValue - The highest value to be tracked by the histogram. Must be a positive integer that is >= (2 * lowestDiscernibleValue).
    
    numberOfSignificantValueDigits - Specifies the precision to use. This is the number of significant decimal digits to which the histogram will maintain value resolution and separation. Must be a non-negative integer between 0 and 5.
- Method Detail
  - recordValue
```
public void recordValue(long value)
                 throws ArrayIndexOutOfBoundsException
```
    Record a value
    
    Specified by:
    
    recordValue in interface ValueRecorder
    
    Parameters:
    
    value - the value to record
    
    Throws:
    
    ArrayIndexOutOfBoundsException - (may throw) if value is exceeds highestTrackableValue
  - recordValueWithCount
```
public void recordValueWithCount(long value,
                                 long count)
                          throws ArrayIndexOutOfBoundsException
```
    Record a value in the histogram (adding to the value's current count)
    
    Specified by:
    
    recordValueWithCount in interface ValueRecorder
    
    Parameters:
    
    value - The value to be recorded
    
    count - The number of occurrences of this value to record
    
    Throws:
    
    ArrayIndexOutOfBoundsException - (may throw) if value is exceeds highestTrackableValue
  - recordValueWithExpectedInterval
```
public void recordValueWithExpectedInterval(long value,
                                            long expectedIntervalBetweenValueSamples)
                                     throws ArrayIndexOutOfBoundsException
```
    Record a value
    To compensate for the loss of sampled values when a recorded value is larger than the expected interval between value samples, Histogram will auto-generate an additional series of decreasingly-smaller (down to the expectedIntervalBetweenValueSamples) value records.
    See related notes AbstractHistogram.recordValueWithExpectedInterval(long, long) for more explanations about coordinated omission and expected interval correction. *
    
    Specified by:
    
    recordValueWithExpectedInterval in interface ValueRecorder
    
    Parameters:
    
    value - The value to record
    
    expectedIntervalBetweenValueSamples - If expectedIntervalBetweenValueSamples is larger than 0, add auto-generated value records as appropriate if value is larger than expectedIntervalBetweenValueSamples
    
    Throws:
    
    ArrayIndexOutOfBoundsException - (may throw) if value is exceeds highestTrackableValue
  - getIntervalHistogram
```
public Histogram getIntervalHistogram()
```
    Get a new instance of an interval histogram, which will include a stable, consistent view of all value counts accumulated since the last interval histogram was taken.
    Calling getIntervalHistogram() will reset the value counts, and start accumulating value counts for the next interval.
    
    Returns:
    
    a histogram containing the value counts accumulated since the last interval histogram was taken.
  - getIntervalHistogram
```
public Histogram getIntervalHistogram(Histogram histogramToRecycle)
```
    Get an interval histogram, which will include a stable, consistent view of all value counts accumulated since the last interval histogram was taken.
    getIntervalHistogram(histogramToRecycle) accepts a previously returned interval histogram that can be recycled internally to avoid allocation and content copying operations, and is therefore significantly more efficient for repeated use than getIntervalHistogram() and getIntervalHistogramInto(). The provided histogramToRecycle must be either be null or an interval histogram returned by a previous call to getIntervalHistogram(histogramToRecycle) or getIntervalHistogram().
    NOTE: The caller is responsible for not recycling the same returned interval histogram more than once. If the same interval histogram instance is recycled more than once, behavior is undefined.
    Calling getIntervalHistogram(histogramToRecycle) will reset the value counts, and start accumulating value counts for the next interval
    
    Parameters:
    
    histogramToRecycle - a previously returned interval histogram (from this instance of Recorder) that may be recycled to avoid allocation and copy operations.
    
    Returns:
    
    a histogram containing the value counts accumulated since the last interval histogram was taken.
  - getIntervalHistogram
```
public Histogram getIntervalHistogram(Histogram histogramToRecycle,
                                      boolean enforeContainingInstance)
```
    Get an interval histogram, which will include a stable, consistent view of all value counts accumulated since the last interval histogram was taken.
    getIntervalHistogram(histogramToRecycle) accepts a previously returned interval histogram that can be recycled internally to avoid allocation and content copying operations, and is therefore significantly more efficient for repeated use than getIntervalHistogram() and getIntervalHistogramInto(). The provided histogramToRecycle must be either be null or an interval histogram returned by a previous call to getIntervalHistogram(histogramToRecycle) or getIntervalHistogram().
    NOTE: The caller is responsible for not recycling the same returned interval histogram more than once. If the same interval histogram instance is recycled more than once, behavior is undefined.
    Calling getIntervalHistogram(histogramToRecycle) will reset the value counts, and start accumulating value counts for the next interval
    
    Parameters:
    
    histogramToRecycle - a previously returned interval histogram that may be recycled to avoid allocation and copy operations.
    
    enforeContainingInstance - if true, will only allow recycling of histograms previously returned from this instance of Recorder. If false, will allow recycling histograms previously returned by other instances of Recorder.
    
    Returns:
    
    a histogram containing the value counts accumulated since the last interval histogram was taken.
  - getIntervalHistogramInto
```
public void getIntervalHistogramInto(Histogram targetHistogram)
```
    Place a copy of the value counts accumulated since accumulated (since the last interval histogram was taken) into targetHistogram. Calling getIntervalHistogramInto() will reset the value counts, and start accumulating value counts for the next interval.
    
    Parameters:
    
    targetHistogram - the histogram into which the interval histogram's data should be copied
  - reset
```
public void reset()
```
    Reset any value counts accumulated thus far.
    
    Specified by:
    
    reset in interface ValueRecorder

Class Recorder

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Recorder

Recorder

Recorder

Method Detail

recordValue

recordValueWithCount

recordValueWithExpectedInterval

getIntervalHistogram

getIntervalHistogram

getIntervalHistogram

getIntervalHistogramInto

reset