org.simpleds.bg
Interface BackgroundTask

All Known Implementing Classes:

AbstractBackgroundTask, DeleteSessionsTask, DeleteTask, IterableEntityTask, IterableTask

public interface BackgroundTask

Unit of work on the Datastore. Implementing classes must implement:

• Idempotence: It is impossible to know in advance how many times a task will be invoked, so it must be capable of resuming work. Specifically, a previous execution may have failed at any point.
• Thread-safe and immutability: Tasks are stored in a static structure, which means that several threads may be executing tasks at the same time. A task should not be modified by the TaskRequest contents.
• Break up into smaller parts: tasks should try to complete in 30 seconds or less, which often means deferring work.

Field Summary

static int

DEFAULT_BATCH_SIZE the default batch size to use

Method Summary

java.lang.Integer	getBatchSize()
java.lang.String	getId()
java.lang.String	getQueueName()
long	proceed(TaskRequest request) Executes this task.
BackgroundTask	withBatchSize(int batchSize) Specifies the number of entities to process per execution, default 150
BackgroundTask	withQueue(java.lang.String queueName) Set the queue name to use.

Field Detail

DEFAULT_BATCH_SIZE

static final int DEFAULT_BATCH_SIZE

the default batch size to use

See Also:

Constant Field Values

Method Detail

proceed

long proceed(TaskRequest request)

Executes this task.

Parameters:

request - the task request

Returns:

the number of entities processed in this batch execution

getId

java.lang.String getId()

Returns:

A unique identifier for this task

withBatchSize

BackgroundTask withBatchSize(int batchSize)

Specifies the number of entities to process per execution, default 150

withQueue

BackgroundTask withQueue(java.lang.String queueName)

Set the queue name to use. If not specified, the default queue will be used.

Parameters:

queueName - the name of the queue to use

Returns:

this instance, for chaining

getQueueName

java.lang.String getQueueName()

Returns:

the Queue to be used by this task when deferring

getBatchSize

java.lang.Integer getBatchSize()

Returns:

the batch size to be used by this task