org.HdrHistogram
Class SynchronizedHistogram

java.lang.Object
  org.HdrHistogram.EncodableHistogram
      org.HdrHistogram.AbstractHistogram
          org.HdrHistogram.Histogram
              org.HdrHistogram.SynchronizedHistogram

All Implemented Interfaces:

Serializable

public class SynchronizedHistogram
extends Histogram

An integer values High Dynamic Range (HDR) Histogram that is synchronized as a whole

A SynchronizedHistogram is a variant of Histogram that is synchronized as a whole, such that queries, copying, and addition operations are atomic with relation to modification on the SynchronizedHistogram, and such that external accessors (e.g. iterations on the histogram data) that synchronize on the SynchronizedHistogram instance can safely assume that no modifications to the histogram data occur within their synchronized block.

It is important to note that synchrionization can result in blocking recoding calls. If non-blocking recoding operations are required, consider using ConcurrentHistogram, AtomicHistogram, or (recommended) Recorder or SingleWriterRecorder which were intended for concurrent operations.

See package description for org.HdrHistogram and Histogram for more details.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.HdrHistogram.AbstractHistogram

AbstractHistogram.AllValues, AbstractHistogram.LinearBucketValues, AbstractHistogram.LogarithmicBucketValues, AbstractHistogram.Percentiles, AbstractHistogram.RecordedValues

Constructor Summary

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

SynchronizedHistogram(int numberOfSignificantValueDigits)
Construct an auto-resizing SynchronizedHistogram with a lowest discernible value of 1 and an auto-adjusting highestTrackableValue.

SynchronizedHistogram(long highestTrackableValue, int numberOfSignificantValueDigits)
Construct a SynchronizedHistogram given the Highest value to be tracked and a number of significant decimal digits.

SynchronizedHistogram(long lowestDiscernibleValue, long highestTrackableValue, int numberOfSignificantValueDigits)
Construct a SynchronizedHistogram given the Lowest and Highest values to be tracked and a number of significant decimal digits.

Method Summary

void	add(AbstractHistogram otherHistogram) Add the contents of another histogram to this one.
SynchronizedHistogram	copy() Create a copy of this histogram, complete with data and everything.
SynchronizedHistogram	copyCorrectedForCoordinatedOmission(long expectedIntervalBetweenValueSamples) Get a copy of this histogram, corrected for coordinated omission.
static SynchronizedHistogram	decodeFromByteBuffer(ByteBuffer buffer, long minBarForHighestTrackableValue) Construct a new histogram by decoding it from a ByteBuffer.
static SynchronizedHistogram	decodeFromCompressedByteBuffer(ByteBuffer buffer, long minBarForHighestTrackableValue) Construct a new histogram by decoding it from a compressed form in a ByteBuffer.
long	getTotalCount() Get the total count of all recorded values in the histogram
void	shiftValuesLeft(int numberOfBinaryOrdersOfMagnitude) Shift recorded values to the left (the equivalent of a << shift operation on all recorded values).
void	shiftValuesRight(int numberOfBinaryOrdersOfMagnitude) Shift recorded values to the right (the equivalent of a >> shift operation on all recorded values).

Methods inherited from class org.HdrHistogram.AbstractHistogram

addWhileCorrectingForCoordinatedOmission, allValues, copyInto, copyIntoCorrectedForCoordinatedOmission, encodeIntoByteBuffer, encodeIntoCompressedByteBuffer, encodeIntoCompressedByteBuffer, equals, getCountAtValue, getCountBetweenValues, getEndTimeStamp, getEstimatedFootprintInBytes, getHighestTrackableValue, getLowestDiscernibleValue, getMaxValue, getMaxValueAsDouble, getMean, getMinNonZeroValue, getMinValue, getNeededByteBufferCapacity, getNumberOfSignificantValueDigits, getPercentileAtOrBelowValue, getStartTimeStamp, getStdDeviation, getValueAtPercentile, highestEquivalentValue, isAutoResize, linearBucketValues, logarithmicBucketValues, lowestEquivalentValue, medianEquivalentValue, nextNonEquivalentValue, outputPercentileDistribution, outputPercentileDistribution, outputPercentileDistribution, percentiles, recordedValues, recordValue, recordValue, recordValueWithCount, recordValueWithExpectedInterval, reset, setAutoResize, setEndTimeStamp, setStartTimeStamp, sizeOfEquivalentValueRange, subtract, valuesAreEquivalent

Methods inherited from class java.lang.Object

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

Constructor Detail

SynchronizedHistogram

public SynchronizedHistogram(int numberOfSignificantValueDigits)

Construct an auto-resizing SynchronizedHistogram with a lowest discernible value of 1 and an auto-adjusting highestTrackableValue. Can auto-reize 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.

SynchronizedHistogram

public SynchronizedHistogram(long highestTrackableValue,
                             int numberOfSignificantValueDigits)

Construct a SynchronizedHistogram 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.

SynchronizedHistogram

public SynchronizedHistogram(long lowestDiscernibleValue,
                             long highestTrackableValue,
                             int numberOfSignificantValueDigits)

Construct a SynchronizedHistogram 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.

SynchronizedHistogram

public SynchronizedHistogram(AbstractHistogram source)

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

Parameters:

source - The source histogram to duplicate

Method Detail

add

public void add(AbstractHistogram otherHistogram)

Description copied from class: AbstractHistogram

Add the contents of another histogram to this one.

Overrides:

add in class AbstractHistogram

Parameters:

otherHistogram - The other histogram.

shiftValuesLeft

public void shiftValuesLeft(int numberOfBinaryOrdersOfMagnitude)

Description copied from class: AbstractHistogram

Shift recorded values to the left (the equivalent of a << shift operation on all recorded values). The configured integer value range limits and value precision setting wull remain unchanged. An ArrayIndexOutOfBoundsException will be thrown if any recorded values may be lost as a result of the attempted operation, reflecting an "overflow" conditions. Expect such an overflow exception if the operation would cause the current maxValue to be scaled to a value that is outside of the covered value range.

Overrides:

shiftValuesLeft in class AbstractHistogram

Parameters:

numberOfBinaryOrdersOfMagnitude - The number of binary orders of magnitude to shift by

shiftValuesRight

public void shiftValuesRight(int numberOfBinaryOrdersOfMagnitude)

Description copied from class: AbstractHistogram

Shift recorded values to the right (the equivalent of a >> shift operation on all recorded values). The configured integer value range limits and value precision setting wull remain unchanged.

Shift right operations that do not underflow are reversible with a shift left operation with no loss of information. An ArrayIndexOutOfBoundsException reflecting an "underflow" conditions will be thrown if any recorded values may lose representation accuracy as a result of the attempted shift operation.

For a shift of a single order of magnitude, expect such an underflow exception if any recorded non-zero values up to [numberOfSignificantValueDigits (rounded up to nearest power of 2) multiplied by (2 ^ numberOfBinaryOrdersOfMagnitude) currently exist in the histogram.

Overrides:

shiftValuesRight in class AbstractHistogram

Parameters:

numberOfBinaryOrdersOfMagnitude - The number of binary orders of magnitude to shift by

copy

public SynchronizedHistogram copy()

Description copied from class: AbstractHistogram

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

Overrides:

copy in class Histogram

Returns:

A distinct copy of this histogram.

copyCorrectedForCoordinatedOmission

public SynchronizedHistogram copyCorrectedForCoordinatedOmission(long expectedIntervalBetweenValueSamples)

Description copied from class: AbstractHistogram

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.

Overrides:

copyCorrectedForCoordinatedOmission in class Histogram

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.

getTotalCount

public long getTotalCount()

Description copied from class: AbstractHistogram

Get the total count of all recorded values in the histogram

Overrides:

getTotalCount in class Histogram

Returns:

the total count of all recorded values in the histogram

decodeFromByteBuffer

public static SynchronizedHistogram decodeFromByteBuffer(ByteBuffer buffer,
                                                         long minBarForHighestTrackableValue)

Construct a new histogram by decoding it from a ByteBuffer.

Parameters:

buffer - The buffer to decode from

minBarForHighestTrackableValue - Force highestTrackableValue to be set at least this high

Returns:

The newly constructed histogram

decodeFromCompressedByteBuffer

public static SynchronizedHistogram decodeFromCompressedByteBuffer(ByteBuffer buffer,
                                                                   long minBarForHighestTrackableValue)
                                                            throws DataFormatException

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

Parameters:

buffer - The buffer to decode from

minBarForHighestTrackableValue - Force highestTrackableValue to be set at least this high

Returns:

The newly constructed histogram

Throws:

DataFormatException - on error parsing/decompressing the buffer