com.alibaba.csp.sentinel.slots.statistic.base

Class LeapArray<T>

java.lang.Object

com.alibaba.csp.sentinel.slots.statistic.base.LeapArray<T>

Type Parameters:

T - type of statistic data

Direct Known Subclasses:

BucketLeapArray, FutureBucketLeapArray, OccupiableBucketLeapArray, UnaryLeapArray

public abstract class LeapArray<T>
extends Object

Basic data structure for statistic metrics in Sentinel.

Leap array use sliding window algorithm to count data. Each bucket cover windowLengthInMs time span, and the total time span is intervalInMs, so the total bucket amount is: sampleCount = intervalInMs / windowLengthInMs.

Author:

jialiang.linjl, Eric Zhao, Carpenter Lee

Field Summary

Fields

Modifier and Type	Field and Description
protected AtomicReferenceArray<WindowWrap<T>>	array
protected int	intervalInMs
protected int	sampleCount
protected int	windowLengthInMs

Constructor Summary

Constructors

Constructor and Description
LeapArray(int sampleCount, int intervalInMs) The total bucket count is: sampleCount = intervalInMs / windowLengthInMs.

Method Summary

Modifier and Type	Method and Description
void	addWaiting(long time, int acquireCount)
protected long	calculateWindowStart(long timeMillis)
long	currentWaiting()
WindowWrap<T>	currentWindow() Get the bucket at current timestamp.
WindowWrap<T>	currentWindow(long timeMillis) Get bucket item at provided timestamp.
void	debug(long time)
int	getIntervalInMs() Get total interval length of the sliding window in milliseconds.
double	getIntervalInSecond() Get total interval length of the sliding window.
WindowWrap<T>	getPreviousWindow() Get the previous bucket item for current timestamp.
WindowWrap<T>	getPreviousWindow(long timeMillis) Get the previous bucket item before provided timestamp.
int	getSampleCount() Get sample count (total amount of buckets).
WindowWrap<T>	getValidHead() Get the valid "head" bucket of the sliding window at current timestamp.
T	getWindowValue(long timeMillis) Get statistic value from bucket for provided timestamp.
boolean	isWindowDeprecated(long time, WindowWrap<T> windowWrap)
boolean	isWindowDeprecated(WindowWrap<T> windowWrap) Check if a bucket is deprecated, which means that the bucket has been behind for at least an entire window time span.
List<WindowWrap<T>>	list() Get valid bucket list for entire sliding window.
List<WindowWrap<T>>	list(long validTime)
List<WindowWrap<T>>	listAll() Get all buckets for entire sliding window including deprecated buckets.
abstract T	newEmptyBucket(long timeMillis) Create a new statistic value for bucket.
protected abstract WindowWrap<T>	resetWindowTo(WindowWrap<T> windowWrap, long startTime) Reset given bucket to provided start time and reset the value.
List<T>	values() Get aggregated value list for entire sliding window.
List<T>	values(long timeMillis)

Methods inherited from class java.lang.Object

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

Field Detail

windowLengthInMs

protected int windowLengthInMs

sampleCount

protected int sampleCount

intervalInMs

protected int intervalInMs

array

protected final AtomicReferenceArray<WindowWrap<T>> array

Constructor Detail

LeapArray

public LeapArray(int sampleCount,
                 int intervalInMs)

The total bucket count is: sampleCount = intervalInMs / windowLengthInMs.

Parameters:

sampleCount - bucket count of the sliding window

intervalInMs - the total time interval of this LeapArray in milliseconds

Method Detail

currentWindow

public WindowWrap<T> currentWindow()

Get the bucket at current timestamp.

Returns:

the bucket at current timestamp

newEmptyBucket

public abstract T newEmptyBucket(long timeMillis)

Create a new statistic value for bucket.

Parameters:

timeMillis - current time in milliseconds

Returns:

the new empty bucket

resetWindowTo

protected abstract WindowWrap<T> resetWindowTo(WindowWrap<T> windowWrap,
                                               long startTime)

Reset given bucket to provided start time and reset the value.

Parameters:

startTime - the start time of the bucket in milliseconds

windowWrap - current bucket

Returns:

new clean bucket at given start time

calculateWindowStart

protected long calculateWindowStart(long timeMillis)

currentWindow

public WindowWrap<T> currentWindow(long timeMillis)

Get bucket item at provided timestamp.

Parameters:

timeMillis - a valid timestamp in milliseconds

Returns:

current bucket item at provided timestamp if the time is valid; null if time is invalid

getPreviousWindow

public WindowWrap<T> getPreviousWindow(long timeMillis)

Get the previous bucket item before provided timestamp.

Parameters:

timeMillis - a valid timestamp in milliseconds

Returns:

the previous bucket item before provided timestamp

getPreviousWindow

public WindowWrap<T> getPreviousWindow()

Get the previous bucket item for current timestamp.

Returns:

the previous bucket item for current timestamp

getWindowValue

public T getWindowValue(long timeMillis)

Get statistic value from bucket for provided timestamp.

Parameters:

timeMillis - a valid timestamp in milliseconds

Returns:

the statistic value if bucket for provided timestamp is up-to-date; otherwise null

isWindowDeprecated

public boolean isWindowDeprecated(WindowWrap<T> windowWrap)

Check if a bucket is deprecated, which means that the bucket has been behind for at least an entire window time span.

Parameters:

windowWrap - a non-null bucket

Returns:

true if the bucket is deprecated; otherwise false

isWindowDeprecated

public boolean isWindowDeprecated(long time,
                                  WindowWrap<T> windowWrap)

list

public List<WindowWrap<T>> list()

Get valid bucket list for entire sliding window. The list will only contain "valid" buckets.

Returns:

valid bucket list for entire sliding window.

list

public List<WindowWrap<T>> list(long validTime)

listAll

public List<WindowWrap<T>> listAll()

Get all buckets for entire sliding window including deprecated buckets.

Returns:

all buckets for entire sliding window

values

public List<T> values()

Get aggregated value list for entire sliding window. The list will only contain value from "valid" buckets.

Returns:

aggregated value list for entire sliding window

values

public List<T> values(long timeMillis)

getValidHead

public WindowWrap<T> getValidHead()

Get the valid "head" bucket of the sliding window at current timestamp.

Returns:

the "head" bucket if it exists and is valid; otherwise null

getSampleCount

public int getSampleCount()

Get sample count (total amount of buckets).

Returns:

sample count

getIntervalInMs

public int getIntervalInMs()

Get total interval length of the sliding window in milliseconds.

Returns:

interval in second

getIntervalInSecond

public double getIntervalInSecond()

Get total interval length of the sliding window.

Returns:

interval in second

debug

public void debug(long time)

currentWaiting

public long currentWaiting()

addWaiting

public void addWaiting(long time,
                       int acquireCount)