Package com.ocient.util

Class Iterators.LazyFanInPriorityQueue

java.lang.Object

com.ocient.util.Iterators.LazyFanInPriorityQueue

All Implemented Interfaces:

com.ibm.asyncutil.iteration.AsyncIterator<CompletableFutures.SQLResult<List<Row>>>, com.ibm.asyncutil.util.AsyncCloseable, QueuePermit

Enclosing class:

Iterators

public static final class Iterators.LazyFanInPriorityQueue
extends Object
implements com.ibm.asyncutil.iteration.AsyncIterator<CompletableFutures.SQLResult<List<Row>>>, QueuePermit

A priority queue for sequenced, asynchronous processing of CompletableFutures.SQLResult<RowBatch> elements.

Nested Class Summary

Nested classes/interfaces inherited from interface com.ibm.asyncutil.iteration.AsyncIterator

com.ibm.asyncutil.iteration.AsyncIterator.End

Constructor Summary

Constructors

Constructor	Description
LazyFanInPriorityQueue(int width, int capacity, SortMode sortMode, String queryId, Consumer<CompletableFutures.SQLResult<RowBatch>> onAdd, BiConsumer<CompletableFutures.SQLResult<RowBatch>,QueuePermit> onRemove, Executor executor)	Constructs a LazyFanInPriorityQueue with the specified parameters.

Method Summary

Modifier and Type	Method	Description
CompletionStage<QueuePermit>	acquirePermit()	Acquires a permit for the queue.
void	init(int streamIndex)	Initializes the queue at the specified index.
CompletionStage<com.ibm.asyncutil.util.Either<com.ibm.asyncutil.iteration.AsyncIterator.End,CompletableFutures.SQLResult<List<Row>>>>	nextStage()
void	releasePermit()	Releases the permit associated with a queue operation.
boolean	send(int streamIndex, CompletableFutures.SQLResult<RowBatch> batchOrEx, QueuePermit permit)	Sends an item to the specified stream index.
void	terminate()	Terminates the queue, disabling send.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.ibm.asyncutil.iteration.AsyncIterator

batch, batch, close, collect, collect, consume, exceptionally, filter, filterApply, filterCompose, find, fold, fold, forEach, fuse, take, takeWhile, thenApply, thenApplyAsync, thenApplyAsync, thenCompose, thenComposeAhead, thenComposeAsync, thenComposeAsync, thenFlatten, thenFlattenAhead

Constructor Details

LazyFanInPriorityQueue

public LazyFanInPriorityQueue(int width,
 int capacity,
 SortMode sortMode,
 String queryId,
 Consumer<CompletableFutures.SQLResult<RowBatch>> onAdd,
 BiConsumer<CompletableFutures.SQLResult<RowBatch>,QueuePermit> onRemove,
 Executor executor)

Constructs a LazyFanInPriorityQueue with the specified parameters.

Parameters:

width - The width of the queue.

capacity - The capacity of the queue.

sortMode - When SortMode.UNSORTED, only the the first stream is used.

queryId - The query ID associated with the queue.

onAdd - Callback to invoke when an element is added.

onRemove - Callback to invoke when an element is removed.

executor - Executor to offload prefetch tasks from the consuming thread.

Method Details

init

public void init(int streamIndex)

Initializes the queue at the specified index.

acquirePermit

public CompletionStage<QueuePermit> acquirePermit()

Acquires a permit for the queue.

releasePermit

public void releasePermit()

Description copied from interface: QueuePermit

Releases the permit associated with a queue operation.

Implementations of this method should release the permit, allowing other operations to proceed. The exact behavior of releasing a permit may vary depending on the specific queue or synchronization mechanism in use.

Specified by:

releasePermit in interface QueuePermit

nextStage

public CompletionStage<com.ibm.asyncutil.util.Either<com.ibm.asyncutil.iteration.AsyncIterator.End,CompletableFutures.SQLResult<List<Row>>>> nextStage()

Specified by:

nextStage in interface com.ibm.asyncutil.iteration.AsyncIterator<CompletableFutures.SQLResult<List<Row>>>

send

public boolean send(int streamIndex,
 CompletableFutures.SQLResult<RowBatch> batchOrEx,
 QueuePermit permit)

Sends an item to the specified stream index.

Parameters:

streamIndex - The index of the queue to which the item is to be sent.

batchOrEx - The SQL result batch or exception to enqueue.

permit - The queue permit associated with the item.

Returns:

True if the item was successfully added to the queue; false if the queue is full.

terminate

public void terminate()

Terminates the queue, disabling send.