Package org.HdrHistogram

Class AbstractHistogram

java.lang.Object
org.HdrHistogram.EncodableHistogram
org.HdrHistogram.AbstractHistogramBase
org.HdrHistogram.AbstractHistogram
All Implemented Interfaces:
Serializable, ValueRecorder
Direct Known Subclasses:
Histogram, IntCountsHistogram, ShortCountsHistogram
public abstract class AbstractHistogram extends AbstractHistogramBase implements ValueRecorder, Serializable

An abstract base class for integer values High Dynamic Range (HDR) Histograms

AbstractHistogram supports the recording and analyzing sampled data value counts across a configurable integer value range with configurable value precision within the range. Value precision is expressed as the number of significant 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.

For example, a Histogram could be configured to track the counts of observed integer values between 0 and 3,600,000,000 while maintaining a value precision of 3 significant digits across that range. Value quantization within the range will thus be no larger than 1/1,000th (or 0.1%) of any value. This example Histogram could be used to track and analyze the counts of observed response times ranging between 1 microsecond and 1 hour in magnitude, while maintaining a value resolution of 1 microsecond up to 1 millisecond, a resolution of 1 millisecond (or better) up to one second, and a resolution of 1 second (or better) up to 1,000 seconds. At it's maximum tracked value (1 hour), it would still maintain a resolution of 3.6 seconds (or better).

See package description for org.HdrHistogram for details.

See Also:

  • Field Details

    • leadingZeroCountBase

      int leadingZeroCountBase
      Number of leading zeros in the largest value that can fit in bucket 0.

    • subBucketHalfCountMagnitude

      int subBucketHalfCountMagnitude

    • unitMagnitude

      int unitMagnitude
      Largest k such that 2^k <= lowestDiscernibleValue

    • subBucketHalfCount

      int subBucketHalfCount

    • subBucketMask

      long subBucketMask
      Biggest value that can fit in bucket 0

    • unitMagnitudeMask

      long unitMagnitudeMask
      Lowest unitMagnitude bits are set

    • maxValue

      volatile long maxValue

    • minNonZeroValue

      volatile long minNonZeroValue

    • maxValueUpdater

      private static final AtomicLongFieldUpdater<AbstractHistogram> maxValueUpdater

    • minNonZeroValueUpdater

      private static final AtomicLongFieldUpdater<AbstractHistogram> minNonZeroValueUpdater

    • serialVersionUID

      private static final long serialVersionUID
      See Also:

    • ENCODING_HEADER_SIZE

      private static final int ENCODING_HEADER_SIZE
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    • V0_ENCODING_HEADER_SIZE

      private static final int V0_ENCODING_HEADER_SIZE
      See Also:

    • V0EncodingCookieBase

      private static final int V0EncodingCookieBase
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    • V0CompressedEncodingCookieBase

      private static final int V0CompressedEncodingCookieBase
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    • V1EncodingCookieBase

      private static final int V1EncodingCookieBase
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    • V1CompressedEncodingCookieBase

      private static final int V1CompressedEncodingCookieBase
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    • V2EncodingCookieBase

      private static final int V2EncodingCookieBase
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    • V2CompressedEncodingCookieBase

      private static final int V2CompressedEncodingCookieBase
      See Also:

    • V2maxWordSizeInBytes

      private static final int V2maxWordSizeInBytes
      See Also:

    • encodingCookieBase

      private static final int encodingCookieBase
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    • compressedEncodingCookieBase

      private static final int compressedEncodingCookieBase
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    • constructorArgsTypes

      private static final Class[] constructorArgsTypes

  • Constructor Details

    • AbstractHistogram

      protected AbstractHistogram(int numberOfSignificantValueDigits)
      Construct an auto-resizing histogram 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 - 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.

    • AbstractHistogram

      protected AbstractHistogram(long lowestDiscernibleValue, long highestTrackableValue, int numberOfSignificantValueDigits)
      Construct a histogram 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 discerned (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 - 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.

    • AbstractHistogram

      protected AbstractHistogram(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 Details

    • getCountAtIndex

      abstract long getCountAtIndex(int index)

    • getCountAtNormalizedIndex

      abstract long getCountAtNormalizedIndex(int index)

    • incrementCountAtIndex

      abstract void incrementCountAtIndex(int index)

    • addToCountAtIndex

      abstract void addToCountAtIndex(int index, long value)

    • setCountAtIndex

      abstract void setCountAtIndex(int index, long value)

    • setCountAtNormalizedIndex

      abstract void setCountAtNormalizedIndex(int index, long value)

    • getNormalizingIndexOffset

      abstract int getNormalizingIndexOffset()

    • setNormalizingIndexOffset

      abstract void setNormalizingIndexOffset(int normalizingIndexOffset)

    • shiftNormalizingIndexByOffset

      abstract void shiftNormalizingIndexByOffset(int offsetToAdd, boolean lowestHalfBucketPopulated, double newIntegerToDoubleValueConversionRatio)

    • setTotalCount

      abstract void setTotalCount(long totalCount)

    • incrementTotalCount

      abstract void incrementTotalCount()

    • addToTotalCount

      abstract void addToTotalCount(long value)

    • clearCounts

      abstract void clearCounts()

    • _getEstimatedFootprintInBytes

      abstract int _getEstimatedFootprintInBytes()

    • resize

      abstract void resize(long newHighestTrackableValue)

    • getTotalCount

      public abstract long getTotalCount()
      Get the total count of all recorded values in the histogram
      Returns:
      the total count of all recorded values in the histogram

    • updatedMaxValue

      private void updatedMaxValue(long value)
      Set internally tracked maxValue to new value if new value is greater than current one. May be overridden by subclasses for synchronization or atomicity purposes.
      Parameters:
      value - new maxValue to set

    • resetMaxValue

      private void resetMaxValue(long maxValue)

    • updateMinNonZeroValue

      private void updateMinNonZeroValue(long value)
      Set internally tracked minNonZeroValue to new value if new value is smaller than current one. May be overridden by subclasses for synchronization or atomicity purposes.
      Parameters:
      value - new minNonZeroValue to set

    • resetMinNonZeroValue

      private void resetMinNonZeroValue(long minNonZeroValue)

    • init

      private void init(long lowestDiscernibleValue, long highestTrackableValue, int numberOfSignificantValueDigits, double integerToDoubleValueConversionRatio, int normalizingIndexOffset)

    • establishSize

      final void establishSize(long newHighestTrackableValue)
      The buckets (each of which has subBucketCount sub-buckets, here assumed to be 2048 as an example) overlap: 
       The 0'th bucket covers from 0...2047 in multiples of 1, using all 2048 sub-buckets
 The 1'th bucket covers from 2048..4097 in multiples of 2, using only the top 1024 sub-buckets
 The 2'th bucket covers from 4096..8191 in multiple of 4, using only the top 1024 sub-buckets
 ...
      Bucket 0 is "special" here. It is the only one that has 2048 entries. All the rest have 1024 entries (because their bottom half overlaps with and is already covered by the all of the previous buckets put together). In other words, the k'th bucket could represent 0 * 2^k to 2048 * 2^k in 2048 buckets with 2^k precision, but the midpoint of 1024 * 2^k = 2048 * 2^(k-1) = the k-1'th bucket's end, so we would use the previous bucket for those lower values as it has better precision.

    • determineArrayLengthNeeded

      final int determineArrayLengthNeeded(long highestTrackableValue)

    • isAutoResize

      public boolean isAutoResize()
      Indicate whether or not the histogram is set to auto-resize and auto-adjust it's highestTrackableValue
      Returns:
      autoResize setting

    • supportsAutoResize

      public boolean supportsAutoResize()
      Indicate whether or not the histogram is capable of supporting auto-resize functionality. Note that this is an indication that enabling auto-resize by calling setAutoResize() is allowed, and NOT that the histogram will actually auto-resize. Use isAutoResize() to determine if the histogram is in auto-resize mode.
      Returns:
      autoResize setting

    • setAutoResize

      public void setAutoResize(boolean autoResize)
      Control whether or not the histogram can auto-resize and auto-adjust it's highestTrackableValue
      Parameters:
      autoResize - autoResize setting

    • recordValue

      public void recordValue(long value) throws ArrayIndexOutOfBoundsException
      Record a value in the histogram
      Specified by:
      recordValue in interface ValueRecorder
      Parameters:
      value - The value to be recorded
      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 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(long). 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.

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

      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

    • recordConvertedDoubleValue

      void recordConvertedDoubleValue(double value)

    • recordConvertedDoubleValueWithCount

      public void recordConvertedDoubleValueWithCount(double value, long count) throws ArrayIndexOutOfBoundsException
      Throws:
      ArrayIndexOutOfBoundsException

    • recordValue

      public void recordValue(long value, long expectedIntervalBetweenValueSamples) throws ArrayIndexOutOfBoundsException
      Deprecated.
      Record a value in the histogram. This deprecated method has identical behavior to recordValueWithExpectedInterval(). It was renamed to avoid ambiguity.
      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

    • updateMinAndMax

      void updateMinAndMax(long value)

    • recordCountAtValue

      private void recordCountAtValue(long count, long value) throws ArrayIndexOutOfBoundsException
      Throws:
      ArrayIndexOutOfBoundsException

    • recordSingleValue

      private void recordSingleValue(long value) throws ArrayIndexOutOfBoundsException
      Throws:
      ArrayIndexOutOfBoundsException

    • handleRecordException

      private void handleRecordException(long count, long value, Exception ex)

    • recordValueWithCountAndExpectedInterval

      private void recordValueWithCountAndExpectedInterval(long value, long count, long expectedIntervalBetweenValueSamples) throws ArrayIndexOutOfBoundsException
      Throws:
      ArrayIndexOutOfBoundsException

    • recordSingleValueWithExpectedInterval

      private void recordSingleValueWithExpectedInterval(long value, long expectedIntervalBetweenValueSamples) throws ArrayIndexOutOfBoundsException
      Throws:
      ArrayIndexOutOfBoundsException

    • reset

      public void reset()
      Reset the contents and stats of this histogram
      Specified by:
      reset in interface ValueRecorder

    • copy

      public abstract AbstractHistogram copy()
      Create a copy of this histogram, complete with data and everything.
      Returns:
      A distinct copy of this histogram.

    • copyCorrectedForCoordinatedOmission

      public abstract AbstractHistogram copyCorrectedForCoordinatedOmission(long 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(AbstractHistogram targetHistogram)
      Copy this histogram into the target histogram, overwriting it's contents.
      Parameters:
      targetHistogram - the histogram to copy into

    • copyIntoCorrectedForCoordinatedOmission

      public void copyIntoCorrectedForCoordinatedOmission(AbstractHistogram targetHistogram, long expectedIntervalBetweenValueSamples)
      Copy this histogram, corrected for coordinated omission, into the target histogram, overwriting it's contents. (see copyCorrectedForCoordinatedOmission(long) 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(AbstractHistogram otherHistogram) throws ArrayIndexOutOfBoundsException
      Add the contents of another histogram to this one.

      As part of adding the contents, the start/end timestamp range of this histogram will be extended to include the start/end timestamp range of the other histogram.

      Parameters:
      otherHistogram - The other histogram.
      Throws:
      ArrayIndexOutOfBoundsException - (may throw) if values in fromHistogram's are higher than highestTrackableValue.

    • subtract

      public void subtract(AbstractHistogram otherHistogram) throws ArrayIndexOutOfBoundsException, IllegalArgumentException
      Subtract the contents of another histogram from this one.

      The start/end timestamps of this histogram will remain unchanged.

      Parameters:
      otherHistogram - The other histogram.
      Throws:
      ArrayIndexOutOfBoundsException - (may throw) if values in otherHistogram's are higher than highestTrackableValue.
      IllegalArgumentException

    • addWhileCorrectingForCoordinatedOmission

      public void addWhileCorrectingForCoordinatedOmission(AbstractHistogram otherHistogram, long 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:
      otherHistogram - The other histogram. highestTrackableValue and largestValueWithSingleUnitResolution 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

    • shiftValuesLeft

      public void shiftValuesLeft(int numberOfBinaryOrdersOfMagnitude)
      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 will 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.
      Parameters:
      numberOfBinaryOrdersOfMagnitude - The number of binary orders of magnitude to shift by

    • shiftValuesLeft

      void shiftValuesLeft(int numberOfBinaryOrdersOfMagnitude, double newIntegerToDoubleValueConversionRatio)

    • nonConcurrentNormalizingIndexShift

      void nonConcurrentNormalizingIndexShift(int shiftAmount, boolean lowestHalfBucketPopulated)

    • shiftLowestHalfBucketContentsLeft

      private void shiftLowestHalfBucketContentsLeft(int shiftAmount, int preShiftZeroIndex)

    • shiftValuesRight

      public void shiftValuesRight(int numberOfBinaryOrdersOfMagnitude)
      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 will 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.

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

    • shiftValuesRight

      void shiftValuesRight(int numberOfBinaryOrdersOfMagnitude, double newIntegerToDoubleValueConversionRatio)

    • 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

    • oneAtATimeHashStep

      private int oneAtATimeHashStep(int h, int v)

    • getLowestDiscernibleValue

      public long getLowestDiscernibleValue()
      get the configured lowestDiscernibleValue
      Returns:
      lowestDiscernibleValue

    • getHighestTrackableValue

      public long getHighestTrackableValue()
      get the configured highestTrackableValue
      Returns:
      highestTrackableValue

    • getNumberOfSignificantValueDigits

      public int getNumberOfSignificantValueDigits()
      get the configured numberOfSignificantValueDigits
      Returns:
      numberOfSignificantValueDigits

    • sizeOfEquivalentValueRange

      public long sizeOfEquivalentValueRange(long 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 size of the range of values equivalent to the given value.

    • lowestEquivalentValue

      public long lowestEquivalentValue(long 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 long highestEquivalentValue(long 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 long medianEquivalentValue(long 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 long nextNonEquivalentValue(long 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(long value1, long 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 with 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 associate with this histogram

    • getMinValue

      public long getMinValue()
      Get the lowest recorded value level in the histogram. If the histogram has no recorded values, the value returned is undefined.
      Returns:
      the Min value recorded in the histogram

    • getMaxValue

      public long getMaxValue()
      Get the highest recorded value level in the histogram. If the histogram has no recorded values, the value returned is undefined.
      Returns:
      the Max value recorded in the histogram

    • getMinNonZeroValue

      public long getMinNonZeroValue()
      Get the lowest recorded non-zero value level in the histogram. If the histogram has no recorded values, the value returned is undefined.
      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 Max value recorded in the histogram

    • 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 long getValueAtPercentile(double percentile)
      Get the value at a given percentile. Returns the largest value that (100% - percentile) [+/- 1 ulp] of the overall recorded value entries in the histogram are either larger than or equivalent to. Returns 0 if no recorded values exist.

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

      Parameters:
      percentile - The percentile for which to return the associated value
      Returns:
      The largest value that (100% - percentile) [+/- 1 ulp] of the overall recorded value entries in the histogram are either larger than or equivalent to. Returns 0 if no recorded values exist.

    • getPercentileAtOrBelowValue

      public double getPercentileAtOrBelowValue(long 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(long, long) 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 long getCountBetweenValues(long lowValue, long 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(long 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 AbstractHistogram.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<HistogramIterationValue> through the histogram using a PercentileIterator

    • linearBucketValues

      public AbstractHistogram.LinearBucketValues linearBucketValues(long 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<HistogramIterationValue> through the histogram using a LinearIterator

    • logarithmicBucketValues

      public AbstractHistogram.LogarithmicBucketValues logarithmicBucketValues(long 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<HistogramIterationValue> through the histogram using a LogarithmicIterator

    • recordedValues

      public AbstractHistogram.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<HistogramIterationValue> through the histogram using a RecordedValuesIterator

    • allValues

      public AbstractHistogram.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<HistogramIterationValue> through the histogram using a AllValuesIterator

    • 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.

    • writeObject

      private void writeObject(ObjectOutputStream o) throws IOException
      Throws:
      IOException

    • readObject

      private void readObject(ObjectInputStream o) throws IOException, ClassNotFoundException
      Throws:
      IOException
      ClassNotFoundException

    • 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

    • getNeededByteBufferCapacity

      int getNeededByteBufferCapacity(int relevantLength)

    • getNeededPayloadByteBufferCapacity

      int getNeededPayloadByteBufferCapacity(int relevantLength)

    • getNeededV0PayloadByteBufferCapacity

      int getNeededV0PayloadByteBufferCapacity(int relevantLength)

    • getEncodingCookie

      private int getEncodingCookie()

    • getCompressedEncodingCookie

      private int getCompressedEncodingCookie()

    • getCookieBase

      private static int getCookieBase(int cookie)

    • getWordSizeInBytesFromCookie

      private static int getWordSizeInBytesFromCookie(int cookie)

    • 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

      static <T extends AbstractHistogram> T decodeFromByteBuffer(ByteBuffer buffer, Class<T> histogramClass, long minBarForHighestTrackableValue)

    • decodeFromByteBuffer

      private static <T extends AbstractHistogram> T decodeFromByteBuffer(ByteBuffer buffer, Class<T> histogramClass, long minBarForHighestTrackableValue, Inflater decompressor) throws DataFormatException
      Throws:
      DataFormatException

    • fillCountsArrayFromSourceBuffer

      private int fillCountsArrayFromSourceBuffer(ByteBuffer sourceBuffer, int lengthInBytes, int wordSizeInBytes)

    • fillBufferFromCountsArray

      void fillBufferFromCountsArray(ByteBuffer buffer)

    • decodeFromCompressedByteBuffer

      static <T extends AbstractHistogram> T decodeFromCompressedByteBuffer(ByteBuffer buffer, Class<T> histogramClass, long minBarForHighestTrackableValue) throws DataFormatException
      Throws:
      DataFormatException

    • recordedValuesToString

      private String recordedValuesToString()

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • establishInternalTackingValues

      void establishInternalTackingValues()

    • establishInternalTackingValues

      void establishInternalTackingValues(int lengthToCover)

    • getBucketsNeededToCoverValue

      int getBucketsNeededToCoverValue(long value)

    • getLengthForNumberOfBuckets

      int getLengthForNumberOfBuckets(int numberOfBuckets)
      If we have N such that subBucketCount * 2^N > max value, we need storage for N+1 buckets, each with enough slots to hold the top half of the subBucketCount (the lower half is covered by previous buckets), and the +1 being used for the lower half of the 0'th bucket. Or, equivalently, we need 1 more bucket to capture the max value if we consider the sub-bucket length to be halved.

    • countsArrayIndex

      int countsArrayIndex(long value)

    • countsArrayIndex

      private int countsArrayIndex(int bucketIndex, int subBucketIndex)

    • getBucketIndex

      int getBucketIndex(long value)
      Returns:
      the lowest (and therefore highest precision) bucket index that can represent the value

    • getSubBucketIndex

      int getSubBucketIndex(long value, int bucketIndex)

    • normalizeIndex

      int normalizeIndex(int index, int normalizingIndexOffset, int arrayLength)
      Returns:
      The value `index - normalizingIndexOffset` modulo arrayLength (always non-negative)

    • valueFromIndex

      private long valueFromIndex(int bucketIndex, int subBucketIndex)

    • valueFromIndex

      final long valueFromIndex(int index)

    • numberOfSubBuckets

      static int numberOfSubBuckets(int numberOfSignificantValueDigits)