org.gridgain.grid.streamer

Interface GridStreamerWindow<E>

All Superinterfaces:

Iterable<E>

All Known Implementing Classes:

GridStreamerBoundedSizeBatchWindow, GridStreamerBoundedSizeSortedWindow, GridStreamerBoundedSizeWindow, GridStreamerBoundedTimeBatchWindow, GridStreamerBoundedTimeWindow, GridStreamerUnboundedWindow, GridStreamerWindowAdapter

public interface GridStreamerWindow<E>
extends Iterable<E>

Streamer rolling window. Rolling windows allow new event to come in, as well as automatically evicting obsolete events on the other side. Windows allow to query into specific time-frame or specific sample size of the events. With windows, you can answer questions like "What are my top 10 best selling products over last 24 hours?", or "Who are my top 10 users out of last 1,000,000 users who logged in?"

GridGain comes with following rolling windows implementations out of the box:

• GridStreamerUnboundedWindow
• GridStreamerBoundedSizeWindow
• GridStreamerBoundedSizeBatchWindow
• GridStreamerBoundedSizeSortedWindow
• GridStreamerBoundedTimeWindow
• GridStreamerBoundedTimeBatchWindow

Streamer window is configured via GridStreamerConfiguration.getWindows() method.

Method Summary

Methods

Modifier and Type	Method and Description
void	clearEvicted() Clears all evicted entries.
E	dequeue() Dequeues last element from windows.
Collection<E>	dequeue(int cnt) Dequeues up to cnt elements from window.
Collection<E>	dequeueAll() Dequeues all elements from window.
boolean	enqueue(E... evts) Adds events to window.
boolean	enqueue(E evt) Adds single event to window.
boolean	enqueueAll(Collection<E> evts) Adds all events to window.
int	evictionQueueSize() Gets number of entries available for eviction.
<K,V> GridStreamerIndex<E,K,V>	index() Gets default index, if default index is not configured then IllegalArgumentException will be thrown.
<K,V> GridStreamerIndex<E,K,V>	index(String name) Gets index by name, if not index with such name was configured then IllegalArgumentException will be thrown.
Collection<GridStreamerIndex<E,?,?>>	indexes() Gets all indexes configured for this window.
String	name() Gets window name.
E	pollEvicted() If window supports eviction, this method will return next evicted element.
Collection<E>	pollEvicted(int cnt) If window supports eviction, this method will return up to cnt evicted elements.
Collection<E>	pollEvictedAll() If window supports eviction, this method will return all available evicted elements.
Collection<E>	pollEvictedBatch() If window supports batch eviction, this method will poll next evicted batch from window.
void	reset() Resets window.
int	size() Gets number of events currently stored in window.
Collection<E>	snapshot(boolean includeIvicted) Create window snapshot.

Methods inherited from interface java.lang.Iterable

iterator

Method Detail

name

String name()

Gets window name.

Returns:

Window name.

index

<K,V> GridStreamerIndex<E,K,V> index()

Gets default index, if default index is not configured then IllegalArgumentException will be thrown.

Type Parameters:

K - Type of the index key.

V - Type of the index value.

Returns:

Index with default name.

index

<K,V> GridStreamerIndex<E,K,V> index(@Nullable
                                   String name)

Gets index by name, if not index with such name was configured then IllegalArgumentException will be thrown.

Type Parameters:

K - Type of the index key.

V - Type of the index value.

Parameters:

name - Name of the index, if null then analogous to index().

Returns:

Index with a given name.

indexes

Collection<GridStreamerIndex<E,?,?>> indexes()

Gets all indexes configured for this window.

Returns:

All indexes configured for this window or empty collection, if no indexes were configured.

reset

void reset()

Resets window. Usually will clear all events from window.

size

int size()

Gets number of events currently stored in window.

Returns:

Current size of the window.

evictionQueueSize

int evictionQueueSize()

Gets number of entries available for eviction.

Returns:

Number of entries available for eviction.

enqueue

boolean enqueue(E evt)
                throws GridException

Adds single event to window.

Parameters:

evt - Event to add.

Returns:

True if event was added.

Throws:

GridException - If index update failed.

enqueue

boolean enqueue(E... evts)
                throws GridException

Adds events to window.

Parameters:

evts - Events to add.

Returns:

Throws:

GridException - If index update failed.

enqueueAll

boolean enqueueAll(Collection<E> evts)
                   throws GridException

Adds all events to window.

Parameters:

evts - Collection of events to add.

Returns:

True if all events were added, false if at least 1 event was skipped.

Throws:

GridException - If index update failed.

dequeue

@Nullable
E dequeue()
          throws GridException

Dequeues last element from windows. Will return null if window is empty.

Returns:

Dequeued element.

Throws:

GridException - If index update failed.

dequeue

Collection<E> dequeue(int cnt)
                      throws GridException

Dequeues up to cnt elements from window. If current window size is less than cnt, will dequeue all elements from window.

Parameters:

cnt - Count to dequeue.

Returns:

Collection of dequeued elements.

Throws:

GridException - If index update failed.

dequeueAll

Collection<E> dequeueAll()
                         throws GridException

Dequeues all elements from window.

Returns:

Collection of dequeued elements.

Throws:

GridException - If index update failed.

pollEvicted

@Nullable
E pollEvicted()
              throws GridException

If window supports eviction, this method will return next evicted element.

Returns:

Polls and returns next evicted event or null if eviction queue is empty or if window does not support eviction.

Throws:

GridException - If index update failed.

pollEvicted

Collection<E> pollEvicted(int cnt)
                          throws GridException

If window supports eviction, this method will return up to cnt evicted elements.

Parameters:

cnt - Number of elements to evict.

Returns:

Collection of evicted elements.

Throws:

GridException - If index update failed.

pollEvictedBatch

Collection<E> pollEvictedBatch()
                               throws GridException

If window supports batch eviction, this method will poll next evicted batch from window. If windows does not support batch eviction but supports eviction, will return collection of single last evicted element. If window does not support eviction, will return empty collection.

Returns:

Next evicted batch.

Throws:

GridException - If index update failed.

pollEvictedAll

Collection<E> pollEvictedAll()
                             throws GridException

If window supports eviction, this method will return all available evicted elements.

Returns:

Collection of evicted elements.

Throws:

GridException - If index update failed.

clearEvicted

void clearEvicted()
                  throws GridException

Clears all evicted entries.

Throws:

GridException - If index update failed.

snapshot

Collection<E> snapshot(boolean includeIvicted)

Create window snapshot. Evicted entries are not included.

Parameters:

includeIvicted - Whether to include evicted entries or not.

Returns:

Window snapshot.