SingleWriterDoubleRecorder (HdrHistogram 2.1.12-SNAPSHOT API)

java.lang.Object
- org.HdrHistogram.SingleWriterDoubleRecorder

All Implemented Interfaces:

DoubleValueRecorder
```
public class SingleWriterDoubleRecorder
extends Object
implements DoubleValueRecorder
```
Records floating point values, and provides stable interval DoubleHistogram 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.
SingleWriterDoubleRecorder expects only a single thread (the "single writer") to call recordValue(double) or recordValueWithExpectedInterval(double, double) at any point in time. It DOES NOT support concurrent recording 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 SingleWriterDoubleRecorder looks like this:
```
 SingleWriterDoubleRecorder recorder = new SingleWriterDoubleRecorder(2); // Two decimal point accuracy
 DoubleHistogram 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
`SingleWriterDoubleRecorder(int numberOfSignificantValueDigits)`	Construct an auto-resizing `SingleWriterDoubleRecorder` using a precision stated as a number of significant decimal digits.
`SingleWriterDoubleRecorder(long highestToLowestValueRatio, int numberOfSignificantValueDigits)`	Construct a `SingleWriterDoubleRecorder` dynamic range of values to cover and a number of significant decimal digits.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`DoubleHistogram`	`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.
`DoubleHistogram`	`getIntervalHistogram(DoubleHistogram histogramToRecycle)`	Get an interval histogram, which will include a stable, consistent view of all value counts accumulated since the last interval histogram was taken.
`DoubleHistogram`	`getIntervalHistogram(DoubleHistogram 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(DoubleHistogram targetHistogram)`	Place a copy of the value counts accumulated since accumulated (since the last interval histogram was taken) into `targetHistogram`.
`void`	`recordValue(double value)`	Record a value
`void`	`recordValueWithCount(double value, long count)`	Record a value in the histogram (adding to the value's current count)
`void`	`recordValueWithExpectedInterval(double value, double 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
  - SingleWriterDoubleRecorder
```
public SingleWriterDoubleRecorder(int numberOfSignificantValueDigits)
```
    Construct an auto-resizing SingleWriterDoubleRecorder using a precision stated as a number of significant decimal digits.
    
    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.
  - SingleWriterDoubleRecorder
```
public SingleWriterDoubleRecorder(long highestToLowestValueRatio,
                                  int numberOfSignificantValueDigits)
```
    Construct a SingleWriterDoubleRecorder dynamic range of values to cover and a number of significant decimal digits.
    
    Parameters:
    
    highestToLowestValueRatio - specifies the dynamic range to use (as a ratio)
    
    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(double value)
```
    Record a value
    
    Specified by:
    
    recordValue in interface DoubleValueRecorder
    
    Parameters:
    
    value - the value to record
    
    Throws:
    
    ArrayIndexOutOfBoundsException - (may throw) if value is exceeds highestTrackableValue
  - recordValueWithCount
```
public void recordValueWithCount(double value,
                                 long count)
                          throws ArrayIndexOutOfBoundsException
```
    Record a value in the histogram (adding to the value's current count)
    
    Specified by:
    
    recordValueWithCount in interface DoubleValueRecorder
    
    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(double value,
                                            double 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 DoubleHistogram.recordValueWithExpectedInterval(double, double) for more explanations about coordinated omission and expected interval correction. *
    
    Specified by:
    
    recordValueWithExpectedInterval in interface DoubleValueRecorder
    
    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 DoubleHistogram 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 DoubleHistogram getIntervalHistogram(DoubleHistogram 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 SingleWriterDoubleRecorder) 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 DoubleHistogram getIntervalHistogram(DoubleHistogram 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 SingleWriterDoubleRecorder. If false, will allow recycling histograms previously returned by other instances of SingleWriterDoubleRecorder.
    
    Returns:
    
    a histogram containing the value counts accumulated since the last interval histogram was taken.
  - getIntervalHistogramInto
```
public void getIntervalHistogramInto(DoubleHistogram targetHistogram)
```
    Place a copy of the value counts accumulated since accumulated (since the last interval histogram was taken) into targetHistogram. Calling getIntervalHistogramInto(org.HdrHistogram.DoubleHistogram)() 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 DoubleValueRecorder

Class SingleWriterDoubleRecorder

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

SingleWriterDoubleRecorder

SingleWriterDoubleRecorder

Method Detail

recordValue

recordValueWithCount

recordValueWithExpectedInterval

getIntervalHistogram

getIntervalHistogram

getIntervalHistogram

getIntervalHistogramInto

reset