org.springframework.metrics.instrument.stats.quantile

Class SlidingWindow<T>

java.lang.Object

org.springframework.metrics.instrument.stats.quantile.SlidingWindow<T>

Type Parameters:

T - any kind of object

All Implemented Interfaces:

java.io.Serializable

public class SlidingWindow<T>
extends java.lang.Object
implements java.io.Serializable

Modified from: https://github.com/mayconbordin/streaminer#quantiles

This class offers a easy to use sliding window implementation. The size of the window is fixed and can't be modified after initializing the SlidingWindow. You can insert elements of the same type of objects into the window. This objects may vary in size (e.g. if you want to save space by adding only new elements to the window whose values vary at least a given threshold, you would add some kind of summary for all the elements that can be covered using one value. In this case the element's size would be total number of elements that fall into the summary).
Because of moving the borders is left to the user this implementation can be used for managing windows that age per time unit as well as per seen element.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
SlidingWindow(java.lang.Integer windowSize) The window size is fixed after initiating an instance of SlidingWindow

Method Summary

Modifier and Type	Method and Description
void	add(T element) Adds a new element to the window.
void	add(T element, java.lang.Integer size) Adds a new element to the window.
T	get(java.lang.Integer index) Returns the element at position index
java.util.Collection<T>	getAll() Returns a collection containing each element in the window
java.util.Collection<java.lang.Integer>	getAllLifeTimes() Returns a collection containing all elements' life times.
java.lang.Integer	getLifeTime(java.lang.Integer index) Returns the remaining life time of the specified element.
T	getNewestElement() Returns the newest element in the window.
T	getOldestElement() Returns the oldest element in the window.
java.lang.Integer	getSize(java.lang.Integer index) Returns the element's size at position index
java.lang.Integer	getWindowSize() Returns the size of this sliding window.
boolean	isEmpty() Checks whether the SlidingWindow is empty
void	slideWindow(java.lang.Integer positions) Moves the window a given number of positions.
void	slideWindowByOnePosition() Just moves the border of the window by one position.

Methods inherited from class java.lang.Object

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

Constructor Detail

SlidingWindow

public SlidingWindow(java.lang.Integer windowSize)

The window size is fixed after initiating an instance of SlidingWindow

Parameters:

windowSize - a (positive) Integer value.

Method Detail

add

public void add(T element)

Adds a new element to the window. The size of this elements is the default size (i.e. 1).
Please note, that no older elements will be discarded until you slide the window manually!

Parameters:

element -

add

public void add(T element,
                java.lang.Integer size)

Adds a new element to the window. The size of this element is specified by the user.
Please note, that no older elements will be discarded until you slide the window manually!

Parameters:

element -

size - - Integer value that specifies the elements size

Throws:

java.lang.RuntimeException - if size is greater than windowSize or a negative Integer

slideWindowByOnePosition

public void slideWindowByOnePosition()

Just moves the border of the window by one position.

slideWindow

public void slideWindow(java.lang.Integer positions)

Moves the window a given number of positions.

Parameters:

positions - - a Integer value representing the elapsed "time"

Throws:

java.lang.RuntimeException - if positions is a negative value

get

public T get(java.lang.Integer index)

Returns the element at position index

Parameters:

index -

Returns:

element of type T

getOldestElement

public T getOldestElement()

Returns the oldest element in the window.

Returns:

element of type T

getNewestElement

public T getNewestElement()

Returns the newest element in the window.

Returns:

element of type T

getAll

public java.util.Collection<T> getAll()

Returns a collection containing each element in the window

Returns:

a Collection of element of type T

getAllLifeTimes

public java.util.Collection<java.lang.Integer> getAllLifeTimes()

Returns a collection containing all elements' life times.

Returns:

a Collection of element of type Integer

getLifeTime

public java.lang.Integer getLifeTime(java.lang.Integer index)

Returns the remaining life time of the specified element.

Parameters:

index -

Returns:

the life time of an element

getWindowSize

public java.lang.Integer getWindowSize()

Returns the size of this sliding window.

Returns:

an Integer that stands for the size of the window

getSize

public java.lang.Integer getSize(java.lang.Integer index)

Returns the element's size at position index

Parameters:

index -

Returns:

Integer value

isEmpty

public boolean isEmpty()

Checks whether the SlidingWindow is empty

Returns:

true if the SlindingWindow contains any element or false if at least one element in the window is active.