org.apache.flink.streaming.api.windowing

Class StreamWindow<T>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractList<E>

java.util.ArrayList<T>

org.apache.flink.streaming.api.windowing.StreamWindow<T>

All Implemented Interfaces:

Serializable, Cloneable, Iterable<T>, Collection<T>, List<T>, RandomAccess, org.apache.flink.util.Collector<T>

public class StreamWindow<T>
extends ArrayList<T>
implements org.apache.flink.util.Collector<T>

Core abstraction for representing windows for WindowedDataStreams. The user can apply transformations on these windows with the appropriate WindowedDataStream methods.

Each stream window consists of a random ID, a number representing the number of partitions for this specific window (ID) and the elements itself. The ID and number of parts will be used to merge the subwindows after distributed transformations.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
int	numberOfParts
int	windowID

Fields inherited from class java.util.AbstractList

modCount

Constructor Summary

Constructors

Constructor and Description
StreamWindow() Creates a new window with a random id
StreamWindow(int windowID) Creates a new window with the specific id
StreamWindow(int windowID, int numberOfParts) Creates a new window with the given id and number of parts
StreamWindow(StreamWindow<T> window) Creates a shallow copy of the window
StreamWindow(StreamWindow<T> window, org.apache.flink.api.common.typeutils.TypeSerializer<T> serializer) Creates a deep copy of the window using the given serializer

Method Summary

Modifier and Type	Method and Description
void	close()
void	collect(T record)
boolean	compatibleWith(StreamWindow<T> otherWindow) Checks whether this window can be merged with the given one.
boolean	equals(Object o)
static <R> StreamWindow<R>	fromElements(R... elements) Creates a new StreamWindow with random id from the given elements
static <R> StreamWindow<R>	merge(List<StreamWindow<R>> windows) Merges compatible windows together.
static <R> StreamWindow<R>	merge(StreamWindow<R>... windows) Merges compatible windows together.
static <X> List<StreamWindow<X>>	partitionBy(StreamWindow<X> streamWindow, org.apache.flink.api.java.functions.KeySelector<X,?> keySelector, boolean withKey) Partitions the window using the given keyselector.
void	setID(int id)
StreamWindow<T>	setNumberOfParts(int n)
static <X> List<StreamWindow<X>>	split(StreamWindow<X> window, int n) Splits the window into n equal (if possible) sizes.
String	toString()

Methods inherited from class java.util.ArrayList

add, add, addAll, addAll, clear, clone, contains, ensureCapacity, forEach, get, indexOf, isEmpty, iterator, lastIndexOf, listIterator, listIterator, remove, remove, removeAll, removeIf, removeRange, replaceAll, retainAll, set, size, sort, spliterator, subList, toArray, toArray, trimToSize

Methods inherited from class java.util.AbstractList

hashCode

Methods inherited from class java.util.AbstractCollection

containsAll

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.List

containsAll, hashCode

Methods inherited from interface java.util.Collection

parallelStream, stream

Field Detail

windowID

public int windowID

numberOfParts

public int numberOfParts

Constructor Detail

StreamWindow

public StreamWindow()

Creates a new window with a random id

StreamWindow

public StreamWindow(int windowID)

Creates a new window with the specific id

Parameters:

windowID - ID of the window

StreamWindow

public StreamWindow(int windowID,
                    int numberOfParts)

Creates a new window with the given id and number of parts

Parameters:

windowID -

numberOfParts -

StreamWindow

public StreamWindow(StreamWindow<T> window)

Creates a shallow copy of the window

Parameters:

window - The window to be copied

StreamWindow

public StreamWindow(StreamWindow<T> window,
                    org.apache.flink.api.common.typeutils.TypeSerializer<T> serializer)

Creates a deep copy of the window using the given serializer

Parameters:

window - The window to be copied

serializer - The serializer used for copying the records.

Method Detail

partitionBy

public static <X> List<StreamWindow<X>> partitionBy(StreamWindow<X> streamWindow,
                                                    org.apache.flink.api.java.functions.KeySelector<X,?> keySelector,
                                                    boolean withKey)
                                             throws Exception

Partitions the window using the given keyselector. A subwindow will be created for each key.

Parameters:

streamWindow - StreamWindow instance to partition

keySelector - The keyselector used for extracting keys.

withKey - Flag to decide whether the key object should be included in the created window

Returns:

A list of the subwindows

Throws:

Exception

split

public static <X> List<StreamWindow<X>> split(StreamWindow<X> window,
                                              int n)

Splits the window into n equal (if possible) sizes.

Parameters:

window - Window to split

n - Number of desired partitions

Returns:

The list of subwindows.

setNumberOfParts

public StreamWindow<T> setNumberOfParts(int n)

setID

public void setID(int id)

compatibleWith

public boolean compatibleWith(StreamWindow<T> otherWindow)

Checks whether this window can be merged with the given one.

Parameters:

otherWindow - The window to test

Returns:

Window compatibility

merge

public static <R> StreamWindow<R> merge(StreamWindow<R>... windows)

Merges compatible windows together.

Parameters:

windows - Windows to merge

Returns:

Merged window

merge

public static <R> StreamWindow<R> merge(List<StreamWindow<R>> windows)

Merges compatible windows together.

Parameters:

windows - Windows to merge

Returns:

Merged window

equals

public boolean equals(Object o)

Specified by:

equals in interface Collection<T>

Specified by:

equals in interface List<T>

Overrides:

equals in class AbstractList<T>

collect

public void collect(T record)

Specified by:

collect in interface org.apache.flink.util.Collector<T>

close

public void close()

Specified by:

close in interface org.apache.flink.util.Collector<T>

toString

public String toString()

Overrides:

toString in class AbstractCollection<T>

fromElements

public static <R> StreamWindow<R> fromElements(R... elements)

Creates a new StreamWindow with random id from the given elements

Parameters:

elements - The elements contained in the resulting window

Returns:

The window