Package org.apache.iotdb.udf.api.customizer.strategy

Class SlidingSizeWindowAccessStrategy

java.lang.Object

org.apache.iotdb.udf.api.customizer.strategy.SlidingSizeWindowAccessStrategy

All Implemented Interfaces:

AccessStrategy

public class SlidingSizeWindowAccessStrategy
extends java.lang.Object
implements AccessStrategy

Used in UDTF.beforeStart(UDFParameters, UDTFConfigurations).

When the access strategy of a UDTF is set to an instance of this class, the method UDTF.transform(RowWindow, PointCollector) of the UDTF will be called to transform the original data. You need to override the method in your own UDTF class.

Sliding size window is a kind of size-based window. Except for the last call, each call of the method UDTF.transform(RowWindow, PointCollector) processes a window with windowSize rows (aligned by time) of the original data and can generate any number of data points.

Sample code:

{@code

See Also:

UDTF, UDTFConfigurations

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.iotdb.udf.api.customizer.strategy.AccessStrategy

AccessStrategy.AccessStrategyType

Constructor Summary

Constructors

Constructor	Description
SlidingSizeWindowAccessStrategy(int windowSize)	Constructor.
SlidingSizeWindowAccessStrategy(int windowSize, int slidingStep)	Constructor.

Method Summary

Modifier and Type	Method	Description
void	check()	Used by the system to check the access strategy.
AccessStrategy.AccessStrategyType	getAccessStrategyType()	Returns the actual access strategy type.
int	getSlidingStep()
int	getWindowSize()

Methods inherited from class java.lang.Object

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

Constructor Detail

SlidingSizeWindowAccessStrategy

public SlidingSizeWindowAccessStrategy(int windowSize,
                                       int slidingStep)

Constructor. You need to specify the number of rows in each sliding size window (except for the last window) and the sliding step to the next window.

Example

Original data points (time, s1, s2):

• (1, 100, null )
• (2, 100, null )
• (3, 100, null )
• (4, 100, 'error')
• (5, 100, null )
• (6, 101, 'error')
• (7, 102, 'error')

Set windowSize to 2 and set slidingStep to 3, windows will be generated as below: Window 0: [(1, 100, null ), (2, 100, null)] Window 1: [(4, 100, 'error'), (5, 100, null)] Window 2: [(7, 102, 'error')]

Parameters:

windowSize - the number of rows in each sliding size window (0 < windowSize)

slidingStep - the number of rows between the first point of the next window and the first point of the current window (0 < slidingStep)

SlidingSizeWindowAccessStrategy

public SlidingSizeWindowAccessStrategy(int windowSize)

Constructor. You need to specify the number of rows in each sliding size window (except for the last window). The sliding step will be set to the same as the window size.

Parameters:

windowSize - the number of rows in each sliding size window (0 < windowSize)

Method Detail

check

public void check()

Description copied from interface: AccessStrategy

Used by the system to check the access strategy.

Specified by:

check in interface AccessStrategy

getWindowSize

public int getWindowSize()

getSlidingStep

public int getSlidingStep()

getAccessStrategyType

public AccessStrategy.AccessStrategyType getAccessStrategyType()

Description copied from interface: AccessStrategy

Returns the actual access strategy type.

Specified by:

getAccessStrategyType in interface AccessStrategy

Returns:

the actual access strategy type