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The official Couchbase JVM Core IO Library
/**
* Written by Gil Tene of Azul Systems, and released to the public domain,
* as explained at http://creativecommons.org/publicdomain/zero/1.0/
*
* @author Gil Tene
*/
package com.couchbase.client.core.deps.org.HdrHistogram;
import java.util.Iterator;
/**
* Used for iterating through histogram values in linear steps. The iteration is
* performed in steps of valueUnitsPerBucket in size, terminating when all recorded histogram
* values are exhausted. Note that each iteration "bucket" includes values up to and including
* the next bucket boundary value.
*/
public class LinearIterator extends AbstractHistogramIterator implements Iterator {
private long valueUnitsPerBucket;
private long currentStepHighestValueReportingLevel;
private long currentStepLowestValueReportingLevel;
/**
* Reset iterator for re-use in a fresh iteration over the same histogram data set.
* @param valueUnitsPerBucket The size (in value units) of each bucket iteration.
*/
public void reset(final long valueUnitsPerBucket) {
reset(histogram, valueUnitsPerBucket);
}
private void reset(final AbstractHistogram histogram, final long valueUnitsPerBucket) {
super.resetIterator(histogram);
this.valueUnitsPerBucket = valueUnitsPerBucket;
this.currentStepHighestValueReportingLevel = valueUnitsPerBucket - 1;
this.currentStepLowestValueReportingLevel = histogram.lowestEquivalentValue(currentStepHighestValueReportingLevel);
}
/**
* @param histogram The histogram this iterator will operate on
* @param valueUnitsPerBucket The size (in value units) of each bucket iteration.
*/
public LinearIterator(final AbstractHistogram histogram, final long valueUnitsPerBucket) {
reset(histogram, valueUnitsPerBucket);
}
@Override
public boolean hasNext() {
if (super.hasNext()) {
return true;
}
// If the next iteration will not move to the next sub bucket index (which is empty if
// if we reached this point), then we are not yet done iterating (we want to iterate
// until we are no longer on a value that has a count, rather than util we first reach
// the last value that has a count. The difference is subtle but important)...
// When this is called, we're about to begin the "next" iteration, so
// currentStepHighestValueReportingLevel has already been incremented, and we use it
// without incrementing its value.
return (currentStepHighestValueReportingLevel < nextValueAtIndex);
}
@Override
void incrementIterationLevel() {
currentStepHighestValueReportingLevel += valueUnitsPerBucket;
currentStepLowestValueReportingLevel = histogram.lowestEquivalentValue(currentStepHighestValueReportingLevel);
}
@Override
long getValueIteratedTo() {
return currentStepHighestValueReportingLevel;
}
@Override
boolean reachedIterationLevel() {
return ((currentValueAtIndex >= currentStepLowestValueReportingLevel) ||
(currentIndex >= histogram.countsArrayLength - 1)) ;
}
}