Package software.amazon.lambda.durable.operation

Class ConcurrencyOperation<T>

java.lang.Object

software.amazon.lambda.durable.operation.BaseDurableOperation

software.amazon.lambda.durable.operation.SerializableDurableOperation<T>

software.amazon.lambda.durable.operation.ConcurrencyOperation<T>

Type Parameters:

T - the result type of this operation

All Implemented Interfaces:

DurableFuture<T>

Direct Known Subclasses:

MapOperation, ParallelOperation

public abstract class ConcurrencyOperation<T>
extends SerializableDurableOperation<T>

Abstract base class for concurrent execution of multiple child context operations.

Encapsulates shared concurrency logic: queue-based concurrency control, success/failure counting, and completion checking. Both ParallelOperation and MapOperation extend this base.

Key design points:

• Does NOT register its own thread — child context threads handle all suspension
• Uses a pending queue + running counter for concurrency control
• Completion is determined by subclass-specific logic via abstract canComplete() and validateItemCount()
• When a child suspends, the running count is NOT decremented

Field Summary

Fields

Modifier and Type	Field	Description
protected final AtomicBoolean	isJoined

Fields inherited from class software.amazon.lambda.durable.operation.BaseDurableOperation

completionFuture, executionManager, parentOperation

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ConcurrencyOperation(OperationIdentifier operationIdentifier, TypeToken<T> resultTypeToken, SerDes resultSerDes, DurableContextImpl durableContext, int maxConcurrency, Integer minSuccessful, Integer toleratedFailureCount)

Method Summary

Modifier and Type	Method	Description
protected <R> ChildContextOperation<R>	createItem(String operationId, String name, Function<DurableContext,R> function, TypeToken<R> resultType, SerDes serDes, OperationSubType branchSubType, DurableContextImpl parentContext)	Creates a child context operation for a single item (branch or iteration).
protected <R> ChildContextOperation<R>	enqueueItem(String name, Function<DurableContext,R> function, TypeToken<R> resultType, SerDes serDes, OperationSubType branchSubType)	Creates and enqueues an item without starting execution.
protected void	executeItems()	Starts execution of all enqueued items.
protected List<ChildContextOperation<?>>	getBranches()
protected abstract void	handleCompletion(ConcurrencyCompletionStatus concurrencyCompletionStatus)	Called when the concurrency operation completes.
protected void	join()	Blocks the calling thread until the concurrency operation reaches a terminal state.

Methods inherited from class software.amazon.lambda.durable.operation.SerializableDurableOperation

deserializeException, deserializeResult, get, serializeException, serializeResult

Methods inherited from class software.amazon.lambda.durable.operation.BaseDurableOperation

execute, getChildOperations, getCompletionFuture, getContext, getCurrentThreadContext, getName, getOperation, getOperationId, getSubType, getType, isOperationCompleted, markAlreadyCompleted, onCheckpointComplete, pollForOperationUpdates, pollForOperationUpdates, registerActiveThread, replay, runUserHandler, sendOperationUpdate, sendOperationUpdateAsync, start, terminateExecution, terminateExecutionWithIllegalDurableOperationException, validateReplay, waitForOperationCompletion

Methods inherited from class java.lang.Object

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

Field Details

isJoined

protected final AtomicBoolean isJoined

Constructor Details

ConcurrencyOperation

protected ConcurrencyOperation(OperationIdentifier operationIdentifier,
 TypeToken<T> resultTypeToken,
 SerDes resultSerDes,
 DurableContextImpl durableContext,
 int maxConcurrency,
 Integer minSuccessful,
 Integer toleratedFailureCount)

Method Details

createItem

protected <R> ChildContextOperation<R> createItem(String operationId,
 String name,
 Function<DurableContext,R> function,
 TypeToken<R> resultType,
 SerDes serDes,
 OperationSubType branchSubType,
 DurableContextImpl parentContext)

Creates a child context operation for a single item (branch or iteration).

Type Parameters:

R - the result type of the child operation

Parameters:

operationId - the unique operation ID for this item

name - the name of this item

function - the user function to execute

resultType - the result type token

branchSubType - the sub-type of the branch operation

parentContext - the parent durable context

Returns:

a new ChildContextOperation

handleCompletion

protected abstract void handleCompletion(ConcurrencyCompletionStatus concurrencyCompletionStatus)

Called when the concurrency operation completes. Subclasses define checkpointing behavior.

enqueueItem

protected <R> ChildContextOperation<R> enqueueItem(String name,
 Function<DurableContext,R> function,
 TypeToken<R> resultType,
 SerDes serDes,
 OperationSubType branchSubType)

Creates and enqueues an item without starting execution. Use executeItems() to begin execution after all items have been enqueued. This prevents early termination from blocking item creation when all items are known upfront (e.g., map operations).

executeItems

protected void executeItems()

Starts execution of all enqueued items.

join

protected void join()

Blocks the calling thread until the concurrency operation reaches a terminal state. Validates item count, handles zero-branch case, then delegates to waitForOperationCompletion() from BaseDurableOperation.

getBranches

protected List<ChildContextOperation<?>> getBranches()