org.HdrHistogram

Class DoubleHistogram

java.lang.Object

org.HdrHistogram.EncodableHistogram

org.HdrHistogram.DoubleHistogram

All Implemented Interfaces:

Serializable, DoubleValueRecorder

Direct Known Subclasses:

ConcurrentDoubleHistogram, PackedDoubleHistogram, SynchronizedDoubleHistogram

public class DoubleHistogram
extends EncodableHistogram
implements DoubleValueRecorder, Serializable

A floating point values High Dynamic Range (HDR) Histogram

It is important to note that DoubleHistogram is not thread-safe, and does not support safe concurrent recording by multiple threads. If concurrent operation is required, consider usings ConcurrentDoubleHistogram, SynchronizedDoubleHistogram, or (recommended) DoubleRecorder or SingleWriterDoubleRecorder which are intended for this purpose.

DoubleHistogram supports the recording and analyzing sampled data value counts across a configurable dynamic range of floating point (double) values, with configurable value precision within the range. Dynamic range is expressed as a ratio between the highest and lowest non-zero values trackable within the histogram at any given time. Value precision is expressed as the number of significant [decimal] digits in the value recording, and provides control over value quantization behavior across the value range and the subsequent value resolution at any given level.

Auto-ranging: Unlike integer value based histograms, the specific value range tracked by a DoubleHistogram is not specified upfront. Only the dynamic range of values that the histogram can cover is (optionally) specified. E.g. When a DoubleHistogram is created to track a dynamic range of 3600000000000 (enough to track values from a nanosecond to an hour), values could be recorded into into it in any consistent unit of time as long as the ratio between the highest and lowest non-zero values stays within the specified dynamic range, so recording in units of nanoseconds (1.0 thru 3600000000000.0), milliseconds (0.000001 thru 3600000.0) seconds (0.000000001 thru 3600.0), hours (1/3.6E12 thru 1.0) will all work just as well.

Auto-resizing: When constructed with no specified dynamic range (or when auto-resize is turned on with setAutoResize(boolean)) a DoubleHistogram will auto-resize its dynamic range to include recorded values as they are encountered. Note that recording calls that cause auto-resizing may take longer to execute, as resizing incurs allocation and copying of internal data structures.

Attempts to record non-zero values that range outside of the specified dynamic range (or exceed the limits of of dynamic range when auto-resizing) may results in ArrayIndexOutOfBoundsException exceptions, either due to overflow or underflow conditions. These exceptions will only be thrown if recording the value would have resulted in discarding or losing the required value precision of values already recorded in the histogram.

See package description for org.HdrHistogram for details.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	DoubleHistogram.AllValues An Iterable<DoubleHistogramIterationValue> through the histogram using a DoubleAllValuesIterator
class	DoubleHistogram.LinearBucketValues An Iterable<DoubleHistogramIterationValue> through the histogram using a DoubleLinearIterator
class	DoubleHistogram.LogarithmicBucketValues An Iterable<DoubleHistogramIterationValue> through the histogram using a DoubleLogarithmicIterator
class	DoubleHistogram.Percentiles An Iterable<DoubleHistogramIterationValue> through the histogram using a DoublePercentileIterator
class	DoubleHistogram.RecordedValues An Iterable<DoubleHistogramIterationValue> through the histogram using a DoubleRecordedValuesIterator

Constructor Summary

Constructors

Modifier	Constructor and Description
	DoubleHistogram(DoubleHistogram source) Construct a DoubleHistogram with the same range settings as a given source, duplicating the source's start/end timestamps (but NOT it's contents)
	DoubleHistogram(int numberOfSignificantValueDigits) Construct a new auto-resizing DoubleHistogram using a precision stated as a number of significant decimal digits.
	DoubleHistogram(int numberOfSignificantValueDigits, Class<? extends AbstractHistogram> internalCountsHistogramClass) Construct a new auto-resizing DoubleHistogram using a precision stated as a number of significant decimal digits.
	DoubleHistogram(long highestToLowestValueRatio, int numberOfSignificantValueDigits) Construct a new DoubleHistogram with the specified dynamic range (provided in highestToLowestValueRatio) and using a precision stated as a number of significant decimal digits.
protected	DoubleHistogram(long highestToLowestValueRatio, int numberOfSignificantValueDigits, Class<? extends AbstractHistogram> internalCountsHistogramClass) Construct a new DoubleHistogram with the specified dynamic range (provided in highestToLowestValueRatio) and using a precision stated as a number of significant decimal digits.

Method Summary

Modifier and Type	Method and Description
void	add(DoubleHistogram fromHistogram) Add the contents of another histogram to this one.
void	addWhileCorrectingForCoordinatedOmission(DoubleHistogram fromHistogram, double expectedIntervalBetweenValueSamples) Add the contents of another histogram to this one, while correcting the incoming data for coordinated omission.
DoubleHistogram.AllValues	allValues() Provide a means of iterating through all histogram values using the finest granularity steps supported by the underlying representation.
DoubleHistogram	copy() Create a copy of this histogram, complete with data and everything.
DoubleHistogram	copyCorrectedForCoordinatedOmission(double expectedIntervalBetweenValueSamples) Get a copy of this histogram, corrected for coordinated omission.
void	copyInto(DoubleHistogram targetHistogram) Copy this histogram into the target histogram, overwriting it's contents.
void	copyIntoCorrectedForCoordinatedOmission(DoubleHistogram targetHistogram, double expectedIntervalBetweenValueSamples) Copy this histogram, corrected for coordinated omission, into the target histogram, overwriting it's contents.
static DoubleHistogram	decodeFromByteBuffer(ByteBuffer buffer, Class<? extends AbstractHistogram> internalCountsHistogramClass, long minBarForHighestToLowestValueRatio) Construct a new DoubleHistogram by decoding it from a ByteBuffer, using a specified AbstractHistogram subclass for tracking internal counts (e.g.
static DoubleHistogram	decodeFromByteBuffer(ByteBuffer buffer, long minBarForHighestToLowestValueRatio) Construct a new DoubleHistogram by decoding it from a ByteBuffer.
static DoubleHistogram	decodeFromCompressedByteBuffer(ByteBuffer buffer, Class<? extends AbstractHistogram> internalCountsHistogramClass, long minBarForHighestToLowestValueRatio) Construct a new DoubleHistogram by decoding it from a compressed form in a ByteBuffer, using a specified AbstractHistogram subclass for tracking internal counts (e.g.
static DoubleHistogram	decodeFromCompressedByteBuffer(ByteBuffer buffer, long minBarForHighestToLowestValueRatio) Construct a new DoubleHistogram by decoding it from a compressed form in a ByteBuffer.
int	encodeIntoByteBuffer(ByteBuffer buffer) Encode this histogram into a ByteBuffer
int	encodeIntoCompressedByteBuffer(ByteBuffer targetBuffer) Encode this histogram in compressed form into a byte array
int	encodeIntoCompressedByteBuffer(ByteBuffer targetBuffer, int compressionLevel) Encode this histogram in compressed form into a byte array
boolean	equals(Object other) Determine if this histogram is equivalent to another.
static DoubleHistogram	fromString(String base64CompressedHistogramString) Construct a new DoubleHistogram by decoding it from a String containing a base64 encoded compressed histogram representation.
long	getCountAtValue(double value) Get the count of recorded values at a specific value (to within the histogram resolution at the value level).
double	getCountBetweenValues(double lowValue, double highValue) Get the count of recorded values within a range of value levels (inclusive to within the histogram's resolution).
long	getEndTimeStamp() get the end time stamp [optionally] stored with this histogram
int	getEstimatedFootprintInBytes() Provide a (conservatively high) estimate of the Histogram's total footprint in bytes
long	getHighestToLowestValueRatio() get the Dynamic range of the histogram: the configured ratio between the highest trackable value and the lowest trackable non zero value at any given time.
double	getIntegerToDoubleValueConversionRatio() Get the current conversion ratio from interval integer value representation to double units.
double	getMaxValue() Get the highest recorded value level in the histogram
double	getMaxValueAsDouble() Get the highest recorded value level in the histogram as a double
double	getMean() Get the computed mean value of all recorded values in the histogram
double	getMinNonZeroValue() Get the lowest recorded non-zero value level in the histogram
double	getMinValue() Get the lowest recorded value level in the histogram
int	getNeededByteBufferCapacity() Get the capacity needed to encode this histogram into a ByteBuffer
int	getNumberOfSignificantValueDigits() get the configured numberOfSignificantValueDigits
double	getPercentileAtOrBelowValue(double value) Get the percentile at a given value.
long	getStartTimeStamp() get the start time stamp [optionally] stored with this histogram
double	getStdDeviation() Get the computed standard deviation of all recorded values in the histogram
String	getTag() get the tag string [optionally] associated with this histogram
long	getTotalCount() Get the total count of all recorded values in the histogram
double	getValueAtPercentile(double percentile) Get the value at a given percentile.
int	hashCode()
double	highestEquivalentValue(double value) Get the highest value that is equivalent to the given value within the histogram's resolution.
boolean	isAutoResize()
DoubleHistogram.LinearBucketValues	linearBucketValues(double valueUnitsPerBucket) Provide a means of iterating through histogram values using linear steps.
DoubleHistogram.LogarithmicBucketValues	logarithmicBucketValues(double valueUnitsInFirstBucket, double logBase) Provide a means of iterating through histogram values at logarithmically increasing levels.
double	lowestEquivalentValue(double value) Get the lowest value that is equivalent to the given value within the histogram's resolution.
double	medianEquivalentValue(double value) Get a value that lies in the middle (rounded up) of the range of values equivalent the given value.
double	nextNonEquivalentValue(double value) Get the next value that is not equivalent to the given value within the histogram's resolution.
void	outputPercentileDistribution(PrintStream printStream, Double outputValueUnitScalingRatio) Produce textual representation of the value distribution of histogram data by percentile.
void	outputPercentileDistribution(PrintStream printStream, int percentileTicksPerHalfDistance, Double outputValueUnitScalingRatio) Produce textual representation of the value distribution of histogram data by percentile.
void	outputPercentileDistribution(PrintStream printStream, int percentileTicksPerHalfDistance, Double outputValueUnitScalingRatio, boolean useCsvFormat) Produce textual representation of the value distribution of histogram data by percentile.
DoubleHistogram.Percentiles	percentiles(int percentileTicksPerHalfDistance) Provide a means of iterating through histogram values according to percentile levels.
DoubleHistogram.RecordedValues	recordedValues() Provide a means of iterating through all recorded histogram values using the finest granularity steps supported by the underlying representation.
void	recordValue(double value) Record a value in the histogram
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 in the histogram.
void	reset() Reset the contents and stats of this histogram
void	setAutoResize(boolean autoResize)
void	setEndTimeStamp(long timeStampMsec) Set the end time stamp value associated with this histogram to a given value.
void	setStartTimeStamp(long timeStampMsec) Set the start time stamp value associated with this histogram to a given value.
void	setTag(String tag) Set the tag string associated with this histogram
double	sizeOfEquivalentValueRange(double value) Get the size (in value units) of the range of values that are equivalent to the given value within the histogram's resolution.
void	subtract(DoubleHistogram otherHistogram) Subtract the contents of another histogram from this one.
boolean	valuesAreEquivalent(double value1, double value2) Determine if two values are equivalent with the histogram's resolution.

Methods inherited from class java.lang.Object

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

Constructor Detail

DoubleHistogram

public DoubleHistogram(int numberOfSignificantValueDigits)

Construct a new auto-resizing DoubleHistogram 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.

DoubleHistogram

public DoubleHistogram(int numberOfSignificantValueDigits,
                       Class<? extends AbstractHistogram> internalCountsHistogramClass)

Construct a new auto-resizing DoubleHistogram using a precision stated as a number of significant decimal digits. The DoubleHistogram will use the specified AbstractHistogram subclass for tracking internal counts (e.g. Histogram, ConcurrentHistogram, SynchronizedHistogram, IntCountsHistogram, ShortCountsHistogram).

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.

internalCountsHistogramClass - The class to use for internal counts tracking

DoubleHistogram

public DoubleHistogram(long highestToLowestValueRatio,
                       int numberOfSignificantValueDigits)

Construct a new DoubleHistogram with the specified dynamic range (provided in highestToLowestValueRatio) and using a precision stated as a number of significant decimal digits.

Parameters:

highestToLowestValueRatio - specifies the dynamic range to use

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.

DoubleHistogram

protected DoubleHistogram(long highestToLowestValueRatio,
                          int numberOfSignificantValueDigits,
                          Class<? extends AbstractHistogram> internalCountsHistogramClass)

Construct a new DoubleHistogram with the specified dynamic range (provided in highestToLowestValueRatio) and using a precision stated as a number of significant decimal digits. The DoubleHistogram will use the specified AbstractHistogram subclass for tracking internal counts (e.g. Histogram, ConcurrentHistogram, SynchronizedHistogram, IntCountsHistogram, ShortCountsHistogram).

Parameters:

highestToLowestValueRatio - specifies the dynamic range to use.

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.

internalCountsHistogramClass - The class to use for internal counts tracking

DoubleHistogram

public DoubleHistogram(DoubleHistogram source)

Construct a DoubleHistogram with the same range settings as a given source, duplicating the source's start/end timestamps (but NOT it's contents)

Parameters:

source - The source histogram to duplicate

Method Detail

isAutoResize

public boolean isAutoResize()

setAutoResize

public void setAutoResize(boolean autoResize)

recordValue

public void recordValue(double value)
                 throws ArrayIndexOutOfBoundsException

Record a value in the histogram

Specified by:

recordValue in interface DoubleValueRecorder

Parameters:

value - The value to be recorded

Throws:

ArrayIndexOutOfBoundsException - (may throw) if value cannot be covered by the histogram's range

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 cannot be covered by the histogram's range

recordValueWithExpectedInterval

public void recordValueWithExpectedInterval(double value,
                                            double expectedIntervalBetweenValueSamples)
                                     throws ArrayIndexOutOfBoundsException

Record a value in the histogram.

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.

Note: This is a at-recording correction method, as opposed to the post-recording correction method provided by copyCorrectedForCoordinatedOmission(double). The use cases for these two methods are mutually exclusive, and only one of the two should be be used on a given data set to correct for the same coordinated omission issue.

See notes in the description of the Histogram calls for an illustration of why this corrective behavior is important.

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 cannot be covered by the histogram's range

reset

public void reset()

Reset the contents and stats of this histogram

Specified by:

reset in interface DoubleValueRecorder

copy

public DoubleHistogram copy()

Create a copy of this histogram, complete with data and everything.

Returns:

A distinct copy of this histogram.

copyCorrectedForCoordinatedOmission

public DoubleHistogram copyCorrectedForCoordinatedOmission(double expectedIntervalBetweenValueSamples)

Get a copy of this histogram, corrected for coordinated omission.

To compensate for the loss of sampled values when a recorded value is larger than the expected interval between value samples, the new histogram will include an auto-generated additional series of decreasingly-smaller (down to the expectedIntervalBetweenValueSamples) value records for each count found in the current histogram that is larger than the expectedIntervalBetweenValueSamples. Note: This is a post-correction method, as opposed to the at-recording correction method provided by recordValueWithExpectedInterval. The two methods are mutually exclusive, and only one of the two should be be used on a given data set to correct for the same coordinated omission issue. by

See notes in the description of the Histogram calls for an illustration of why this corrective behavior is important.

Parameters:

expectedIntervalBetweenValueSamples - If expectedIntervalBetweenValueSamples is larger than 0, add auto-generated value records as appropriate if value is larger than expectedIntervalBetweenValueSamples

Returns:

a copy of this histogram, corrected for coordinated omission.

copyInto

public void copyInto(DoubleHistogram targetHistogram)

Copy this histogram into the target histogram, overwriting it's contents.

Parameters:

targetHistogram - the histogram to copy into

copyIntoCorrectedForCoordinatedOmission

public void copyIntoCorrectedForCoordinatedOmission(DoubleHistogram targetHistogram,
                                                    double expectedIntervalBetweenValueSamples)

Copy this histogram, corrected for coordinated omission, into the target histogram, overwriting it's contents. (see copyCorrectedForCoordinatedOmission(double) for more detailed explanation about how correction is applied)

Parameters:

targetHistogram - the histogram to copy into

expectedIntervalBetweenValueSamples - If expectedIntervalBetweenValueSamples is larger than 0, add auto-generated value records as appropriate if value is larger than expectedIntervalBetweenValueSamples

add

public void add(DoubleHistogram fromHistogram)
         throws ArrayIndexOutOfBoundsException

Add the contents of another histogram to this one.

Parameters:

fromHistogram - The other histogram.

Throws:

ArrayIndexOutOfBoundsException - (may throw) if values in fromHistogram's cannot be covered by this histogram's range

addWhileCorrectingForCoordinatedOmission

public void addWhileCorrectingForCoordinatedOmission(DoubleHistogram fromHistogram,
                                                     double expectedIntervalBetweenValueSamples)

Add the contents of another histogram to this one, while correcting the incoming data for coordinated omission.

To compensate for the loss of sampled values when a recorded value is larger than the expected interval between value samples, the values added will include an auto-generated additional series of decreasingly-smaller (down to the expectedIntervalBetweenValueSamples) value records for each count found in the current histogram that is larger than the expectedIntervalBetweenValueSamples. Note: This is a post-recording correction method, as opposed to the at-recording correction method provided by recordValueWithExpectedInterval. The two methods are mutually exclusive, and only one of the two should be be used on a given data set to correct for the same coordinated omission issue. by

See notes in the description of the Histogram calls for an illustration of why this corrective behavior is important.

Parameters:

fromHistogram - Other histogram. highestToLowestValueRatio and numberOfSignificantValueDigits must match.

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 values exceed highestTrackableValue

subtract

public void subtract(DoubleHistogram otherHistogram)

Subtract the contents of another histogram from this one.

Parameters:

otherHistogram - The other histogram.

Throws:

ArrayIndexOutOfBoundsException - (may throw) if values in fromHistogram's cannot be covered by this histogram's range

equals

public boolean equals(Object other)

Determine if this histogram is equivalent to another.

Overrides:

equals in class Object

Parameters:

other - the other histogram to compare to

Returns:

True if this histogram are equivalent with the other.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

getTotalCount

public long getTotalCount()

Get the total count of all recorded values in the histogram

Returns:

the total count of all recorded values in the histogram

getIntegerToDoubleValueConversionRatio

public double getIntegerToDoubleValueConversionRatio()

Get the current conversion ratio from interval integer value representation to double units. (keep in mind that this can change because it is auto ranging). This ratio can be useful for converting integer values found in iteration, although the preferred form for accessing iteration values would be to use the getDoubleValueIteratedTo() and getDoubleValueIteratedFrom() accessors to HistogramIterationValue iterated values.

Returns:

the current conversion ratio from interval integer value representation to double units.

getNumberOfSignificantValueDigits

public int getNumberOfSignificantValueDigits()

get the configured numberOfSignificantValueDigits

Returns:

numberOfSignificantValueDigits

getHighestToLowestValueRatio

public long getHighestToLowestValueRatio()

get the Dynamic range of the histogram: the configured ratio between the highest trackable value and the lowest trackable non zero value at any given time.

Returns:

the dynamic range of the histogram, expressed as the ratio between the highest trackable value and the lowest trackable non zero value at any given time.

sizeOfEquivalentValueRange

public double sizeOfEquivalentValueRange(double value)

Get the size (in value units) of the range of values that are equivalent to the given value within the histogram's resolution. Where "equivalent" means that value samples recorded for any two equivalent values are counted in a common total count.

Parameters:

value - The given value

Returns:

The lowest value that is equivalent to the given value within the histogram's resolution.

lowestEquivalentValue

public double lowestEquivalentValue(double value)

Get the lowest value that is equivalent to the given value within the histogram's resolution. Where "equivalent" means that value samples recorded for any two equivalent values are counted in a common total count.

Parameters:

value - The given value

Returns:

The lowest value that is equivalent to the given value within the histogram's resolution.

highestEquivalentValue

public double highestEquivalentValue(double value)

Get the highest value that is equivalent to the given value within the histogram's resolution. Where "equivalent" means that value samples recorded for any two equivalent values are counted in a common total count.

Parameters:

value - The given value

Returns:

The highest value that is equivalent to the given value within the histogram's resolution.

medianEquivalentValue

public double medianEquivalentValue(double value)

Get a value that lies in the middle (rounded up) of the range of values equivalent the given value. Where "equivalent" means that value samples recorded for any two equivalent values are counted in a common total count.

Parameters:

value - The given value

Returns:

The value lies in the middle (rounded up) of the range of values equivalent the given value.

nextNonEquivalentValue

public double nextNonEquivalentValue(double value)

Get the next value that is not equivalent to the given value within the histogram's resolution. Where "equivalent" means that value samples recorded for any two equivalent values are counted in a common total count.

Parameters:

value - The given value

Returns:

The next value that is not equivalent to the given value within the histogram's resolution.

valuesAreEquivalent

public boolean valuesAreEquivalent(double value1,
                                   double value2)

Determine if two values are equivalent with the histogram's resolution. Where "equivalent" means that value samples recorded for any two equivalent values are counted in a common total count.

Parameters:

value1 - first value to compare

value2 - second value to compare

Returns:

True if values are equivalent to within the histogram's resolution.

getEstimatedFootprintInBytes

public int getEstimatedFootprintInBytes()

Provide a (conservatively high) estimate of the Histogram's total footprint in bytes

Returns:

a (conservatively high) estimate of the Histogram's total footprint in bytes

getStartTimeStamp

public long getStartTimeStamp()

get the start time stamp [optionally] stored with this histogram

Specified by:

getStartTimeStamp in class EncodableHistogram

Returns:

the start time stamp [optionally] stored with this histogram

setStartTimeStamp

public void setStartTimeStamp(long timeStampMsec)

Set the start time stamp value associated with this histogram to a given value.

Specified by:

setStartTimeStamp in class EncodableHistogram

Parameters:

timeStampMsec - the value to set the time stamp to, [by convention] in msec since the epoch.

getEndTimeStamp

public long getEndTimeStamp()

get the end time stamp [optionally] stored with this histogram

Specified by:

getEndTimeStamp in class EncodableHistogram

Returns:

the end time stamp [optionally] stored with this histogram

setEndTimeStamp

public void setEndTimeStamp(long timeStampMsec)

Set the end time stamp value associated with this histogram to a given value.

Specified by:

setEndTimeStamp in class EncodableHistogram

Parameters:

timeStampMsec - the value to set the time stamp to, [by convention] in msec since the epoch.

getTag

public String getTag()

get the tag string [optionally] associated with this histogram

Specified by:

getTag in class EncodableHistogram

Returns:

tag string [optionally] associated with this histogram

setTag

public void setTag(String tag)

Set the tag string associated with this histogram

Specified by:

setTag in class EncodableHistogram

Parameters:

tag - the tag string to assciate with this histogram

getMinValue

public double getMinValue()

Get the lowest recorded value level in the histogram

Returns:

the Min value recorded in the histogram

getMaxValue

public double getMaxValue()

Get the highest recorded value level in the histogram

Returns:

the Max value recorded in the histogram

getMinNonZeroValue

public double getMinNonZeroValue()

Get the lowest recorded non-zero value level in the histogram

Returns:

the lowest recorded non-zero value level in the histogram

getMaxValueAsDouble

public double getMaxValueAsDouble()

Get the highest recorded value level in the histogram as a double

Specified by:

getMaxValueAsDouble in class EncodableHistogram

Returns:

the highest recorded value level in the histogram as a double

getMean

public double getMean()

Get the computed mean value of all recorded values in the histogram

Returns:

the mean value (in value units) of the histogram data

getStdDeviation

public double getStdDeviation()

Get the computed standard deviation of all recorded values in the histogram

Returns:

the standard deviation (in value units) of the histogram data

getValueAtPercentile

public double getValueAtPercentile(double percentile)

Get the value at a given percentile. When the percentile is > 0.0, the value returned is the value that the given the given percentage of the overall recorded value entries in the histogram are either smaller than or equivalent to. When the percentile is 0.0, the value returned is the value that all value entries in the histogram are either larger than or equivalent to.

Note that two values are "equivalent" in this statement if valuesAreEquivalent(double, double) would return true.

Parameters:

percentile - The percentile for which to return the associated value

Returns:

The value that the given percentage of the overall recorded value entries in the histogram are either smaller than or equivalent to. When the percentile is 0.0, returns the value that all value entries in the histogram are either larger than or equivalent to.

getPercentileAtOrBelowValue

public double getPercentileAtOrBelowValue(double value)

Get the percentile at a given value. The percentile returned is the percentile of values recorded in the histogram that are smaller than or equivalent to the given value.

Note that two values are "equivalent" in this statement if valuesAreEquivalent(double, double) would return true.

Parameters:

value - The value for which to return the associated percentile

Returns:

The percentile of values recorded in the histogram that are smaller than or equivalent to the given value.

getCountBetweenValues

public double getCountBetweenValues(double lowValue,
                                    double highValue)
                             throws ArrayIndexOutOfBoundsException

Get the count of recorded values within a range of value levels (inclusive to within the histogram's resolution).

Parameters:

lowValue - The lower value bound on the range for which to provide the recorded count. Will be rounded down with lowestEquivalentValue.

highValue - The higher value bound on the range for which to provide the recorded count. Will be rounded up with highestEquivalentValue.

Returns:

the total count of values recorded in the histogram within the value range that is >= lowestEquivalentValue(lowValue) and <= highestEquivalentValue(highValue)

Throws:

ArrayIndexOutOfBoundsException

getCountAtValue

public long getCountAtValue(double value)
                     throws ArrayIndexOutOfBoundsException

Get the count of recorded values at a specific value (to within the histogram resolution at the value level).

Parameters:

value - The value for which to provide the recorded count

Returns:

The total count of values recorded in the histogram within the value range that is >= lowestEquivalentValue(value) and <= highestEquivalentValue(value)

Throws:

ArrayIndexOutOfBoundsException

percentiles

public DoubleHistogram.Percentiles percentiles(int percentileTicksPerHalfDistance)

Provide a means of iterating through histogram values according to percentile levels. The iteration is performed in steps that start at 0% and reduce their distance to 100% according to the percentileTicksPerHalfDistance parameter, ultimately reaching 100% when all recorded histogram values are exhausted.

Parameters:

percentileTicksPerHalfDistance - The number of iteration steps per half-distance to 100%.

Returns:

An Iterable<DoubleHistogramIterationValue> through the histogram using a DoublePercentileIterator

linearBucketValues

public DoubleHistogram.LinearBucketValues linearBucketValues(double valueUnitsPerBucket)

Provide a means of iterating through histogram values using linear steps. The iteration is performed in steps of valueUnitsPerBucket in size, terminating when all recorded histogram values are exhausted.

Parameters:

valueUnitsPerBucket - The size (in value units) of the linear buckets to use

Returns:

An Iterable<DoubleHistogramIterationValue> through the histogram using a DoubleLinearIterator

logarithmicBucketValues

public DoubleHistogram.LogarithmicBucketValues logarithmicBucketValues(double valueUnitsInFirstBucket,
                                                                       double logBase)

Provide a means of iterating through histogram values at logarithmically increasing levels. The iteration is performed in steps that start at valueUnitsInFirstBucket and increase exponentially according to logBase, terminating when all recorded histogram values are exhausted.

Parameters:

valueUnitsInFirstBucket - The size (in value units) of the first bucket in the iteration

logBase - The multiplier by which bucket sizes will grow in each iteration step

Returns:

An Iterable<DoubleHistogramIterationValue> through the histogram using a DoubleLogarithmicIterator

recordedValues

public DoubleHistogram.RecordedValues recordedValues()

Provide a means of iterating through all recorded histogram values using the finest granularity steps supported by the underlying representation. The iteration steps through all non-zero recorded value counts, and terminates when all recorded histogram values are exhausted.

Returns:

An Iterable<DoubleHistogramIterationValue> through the histogram using a DoubleRecordedValuesIterator

allValues

public DoubleHistogram.AllValues allValues()

Provide a means of iterating through all histogram values using the finest granularity steps supported by the underlying representation. The iteration steps through all possible unit value levels, regardless of whether or not there were recorded values for that value level, and terminates when all recorded histogram values are exhausted.

Returns:

An Iterable<DoubleHistogramIterationValue> through the histogram using a DoubleAllValuesIterator

outputPercentileDistribution

public void outputPercentileDistribution(PrintStream printStream,
                                         Double outputValueUnitScalingRatio)

Produce textual representation of the value distribution of histogram data by percentile. The distribution is output with exponentially increasing resolution, with each exponentially decreasing half-distance containing five (5) percentile reporting tick points.

Parameters:

printStream - Stream into which the distribution will be output

outputValueUnitScalingRatio - The scaling factor by which to divide histogram recorded values units in output

outputPercentileDistribution

public void outputPercentileDistribution(PrintStream printStream,
                                         int percentileTicksPerHalfDistance,
                                         Double outputValueUnitScalingRatio)

Produce textual representation of the value distribution of histogram data by percentile. The distribution is output with exponentially increasing resolution, with each exponentially decreasing half-distance containing dumpTicksPerHalf percentile reporting tick points.

Parameters:

printStream - Stream into which the distribution will be output

percentileTicksPerHalfDistance - The number of reporting points per exponentially decreasing half-distance

outputValueUnitScalingRatio - The scaling factor by which to divide histogram recorded values units in output

outputPercentileDistribution

public void outputPercentileDistribution(PrintStream printStream,
                                         int percentileTicksPerHalfDistance,
                                         Double outputValueUnitScalingRatio,
                                         boolean useCsvFormat)

Produce textual representation of the value distribution of histogram data by percentile. The distribution is output with exponentially increasing resolution, with each exponentially decreasing half-distance containing dumpTicksPerHalf percentile reporting tick points.

Parameters:

printStream - Stream into which the distribution will be output

percentileTicksPerHalfDistance - The number of reporting points per exponentially decreasing half-distance

outputValueUnitScalingRatio - The scaling factor by which to divide histogram recorded values units in output

useCsvFormat - Output in CSV format if true. Otherwise use plain text form.

getNeededByteBufferCapacity

public int getNeededByteBufferCapacity()

Get the capacity needed to encode this histogram into a ByteBuffer

Specified by:

getNeededByteBufferCapacity in class EncodableHistogram

Returns:

the capacity needed to encode this histogram into a ByteBuffer

encodeIntoByteBuffer

public int encodeIntoByteBuffer(ByteBuffer buffer)

Encode this histogram into a ByteBuffer

Parameters:

buffer - The buffer to encode into

Returns:

The number of bytes written to the buffer

encodeIntoCompressedByteBuffer

public int encodeIntoCompressedByteBuffer(ByteBuffer targetBuffer,
                                          int compressionLevel)

Encode this histogram in compressed form into a byte array

Specified by:

encodeIntoCompressedByteBuffer in class EncodableHistogram

Parameters:

targetBuffer - The buffer to encode into

compressionLevel - Compression level (for java.util.zip.Deflater).

Returns:

The number of bytes written to the buffer

encodeIntoCompressedByteBuffer

public int encodeIntoCompressedByteBuffer(ByteBuffer targetBuffer)

Encode this histogram in compressed form into a byte array

Parameters:

targetBuffer - The buffer to encode into

Returns:

The number of bytes written to the array

decodeFromByteBuffer

public static DoubleHistogram decodeFromByteBuffer(ByteBuffer buffer,
                                                   long minBarForHighestToLowestValueRatio)

Construct a new DoubleHistogram by decoding it from a ByteBuffer.

Parameters:

buffer - The buffer to decode from

minBarForHighestToLowestValueRatio - Force highestTrackableValue to be set at least this high

Returns:

The newly constructed DoubleHistogram

decodeFromByteBuffer

public static DoubleHistogram decodeFromByteBuffer(ByteBuffer buffer,
                                                   Class<? extends AbstractHistogram> internalCountsHistogramClass,
                                                   long minBarForHighestToLowestValueRatio)

Construct a new DoubleHistogram by decoding it from a ByteBuffer, using a specified AbstractHistogram subclass for tracking internal counts (e.g. Histogram, ConcurrentHistogram, SynchronizedHistogram, IntCountsHistogram, ShortCountsHistogram).

Parameters:

buffer - The buffer to decode from

internalCountsHistogramClass - The class to use for internal counts tracking

minBarForHighestToLowestValueRatio - Force highestTrackableValue to be set at least this high

Returns:

The newly constructed DoubleHistogram

decodeFromCompressedByteBuffer

public static DoubleHistogram decodeFromCompressedByteBuffer(ByteBuffer buffer,
                                                             long minBarForHighestToLowestValueRatio)
                                                      throws DataFormatException

Construct a new DoubleHistogram by decoding it from a compressed form in a ByteBuffer.

Parameters:

buffer - The buffer to decode from

minBarForHighestToLowestValueRatio - Force highestTrackableValue to be set at least this high

Returns:

The newly constructed DoubleHistogram

Throws:

DataFormatException - on error parsing/decompressing the buffer

decodeFromCompressedByteBuffer

public static DoubleHistogram decodeFromCompressedByteBuffer(ByteBuffer buffer,
                                                             Class<? extends AbstractHistogram> internalCountsHistogramClass,
                                                             long minBarForHighestToLowestValueRatio)
                                                      throws DataFormatException

Construct a new DoubleHistogram by decoding it from a compressed form in a ByteBuffer, using a specified AbstractHistogram subclass for tracking internal counts (e.g. Histogram, AtomicHistogram, SynchronizedHistogram, IntCountsHistogram, ShortCountsHistogram).

Parameters:

buffer - The buffer to decode from

internalCountsHistogramClass - The class to use for internal counts tracking

minBarForHighestToLowestValueRatio - Force highestTrackableValue to be set at least this high

Returns:

The newly constructed DoubleHistogram

Throws:

DataFormatException - on error parsing/decompressing the buffer

fromString

public static DoubleHistogram fromString(String base64CompressedHistogramString)
                                  throws DataFormatException

Construct a new DoubleHistogram by decoding it from a String containing a base64 encoded compressed histogram representation.

Parameters:

base64CompressedHistogramString - A string containing a base64 encoding of a compressed histogram

Returns:

A DoubleHistogram decoded from the string

Throws:

DataFormatException - on error parsing/decompressing the input