Package org.duracloud.common.queue.aws

Class SQSTaskQueue

java.lang.Object

org.duracloud.common.queue.aws.SQSTaskQueue

All Implemented Interfaces:

TaskQueue

public class SQSTaskQueue
extends Object
implements TaskQueue

SQSTaskQueue acts as the interface for interacting with an Amazon Simple Queue Service (SQS) queue. This class provides a way to interact with a remote SQS Queue, it emulates the functionality of a queue.

Author:

Erik Paulsson Date: 10/21/13

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	SQSTaskQueue.MsgProp

Constructor Summary

Constructors

Constructor	Description
SQSTaskQueue(com.amazonaws.services.sqs.AmazonSQS sqsClient, String queueName)
SQSTaskQueue(String queueName)	Creates a SQSTaskQueue that serves as a handle to interacting with a remote Amazon SQS Queue.

Method Summary

Modifier and Type	Method	Description
void	deleteTask(Task task)	Deletes a task from the queue.
void	deleteTasks(Set<Task> tasks)	Deletes a set of tasks
void	extendVisibilityTimeout(Task task)	Responsible for robustly extending the visibility timeout of a Task.
String	getName()	A name identifying the queue used for logging and analysis purposes.
protected Task	marshallTask(com.amazonaws.services.sqs.model.Message msg)
void	put(Set<Task> tasks)	Puts multiple tasks on the queue using batch puts.
void	put(Task task)	puts a task on the queue
void	put(Task... tasks)	Convenience method that calls put(Set)
void	requeue(Task task)	Requeues the task by deleting the task, incrementing the "attempts" counter, and re-adding back to the queue.
Integer	size()
Integer	sizeIncludingInvisibleAndDelayed()
Task	take()	Blocks until a task is available
Set<Task>	take(int maxTasks)	Take a max of specified number of tasks.
protected String	unmarshallTask(Task task)

Methods inherited from class java.lang.Object

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

Constructor Detail

SQSTaskQueue

public SQSTaskQueue(String queueName)

Creates a SQSTaskQueue that serves as a handle to interacting with a remote Amazon SQS Queue. The AmazonSQSClient will search for Amazon credentials on the system as described here: http://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/auth/DefaultAWSCredentialsProviderChain.html Moreover, it is possible to set the region to use via the AWS_REGION environment variable or one of the other methods described here: http://docs.aws.amazon.com/sdk-for-java/v1/developer-guide/java-dg-region-selection.html

SQSTaskQueue

public SQSTaskQueue(com.amazonaws.services.sqs.AmazonSQS sqsClient,
                    String queueName)

Method Detail

getName

public String getName()

Description copied from interface: TaskQueue

A name identifying the queue used for logging and analysis purposes.

Specified by:

getName in interface TaskQueue

Returns:

marshallTask

protected Task marshallTask(com.amazonaws.services.sqs.model.Message msg)

unmarshallTask

protected String unmarshallTask(Task task)

put

public void put(Task task)

Description copied from interface: TaskQueue

puts a task on the queue

Specified by:

put in interface TaskQueue

put

public void put(Task... tasks)

Convenience method that calls put(Set)

Specified by:

put in interface TaskQueue

Parameters:

tasks -

put

public void put(Set<Task> tasks)

Puts multiple tasks on the queue using batch puts. The tasks argument can contain more than 10 Tasks, in that case there will be multiple SQS batch send requests made each containing up to 10 messages.

Specified by:

put in interface TaskQueue

Parameters:

tasks -

take

public Set<Task> take(int maxTasks)
               throws TimeoutException

Description copied from interface: TaskQueue

Take a max of specified number of tasks. Blocks until at least one task is available.

Specified by:

take in interface TaskQueue

Parameters:

maxTasks - to take from queue. Must be between 1 and 10 inclusive.

Returns:

Throws:

TimeoutException

take

public Task take()
          throws TimeoutException

Description copied from interface: TaskQueue

Blocks until a task is available

Specified by:

take in interface TaskQueue

Returns:

Throws:

TimeoutException

extendVisibilityTimeout

public void extendVisibilityTimeout(Task task)
                             throws TaskNotFoundException

Description copied from interface: TaskQueue

Responsible for robustly extending the visibility timeout of a Task.

Specified by:

extendVisibilityTimeout in interface TaskQueue

Throws:

TaskNotFoundException

deleteTask

public void deleteTask(Task task)
                throws TaskNotFoundException

Description copied from interface: TaskQueue

Deletes a task from the queue.

Specified by:

deleteTask in interface TaskQueue

Throws:

TaskNotFoundException

deleteTasks

public void deleteTasks(Set<Task> tasks)
                 throws TaskException

Description copied from interface: TaskQueue

Deletes a set of tasks

Specified by:

deleteTasks in interface TaskQueue

Throws:

TaskException

requeue

public void requeue(Task task)

Description copied from interface: TaskQueue

Requeues the task by deleting the task, incrementing the "attempts" counter, and re-adding back to the queue. Any subsequent calls on the requeued task via the task queue should fail due to the task not being found.

Specified by:

requeue in interface TaskQueue

size

public Integer size()

Specified by:

size in interface TaskQueue

Returns:

The approximate number of elements in this queue (does not include invisible and delayed tasks).

sizeIncludingInvisibleAndDelayed

public Integer sizeIncludingInvisibleAndDelayed()

Specified by:

sizeIncludingInvisibleAndDelayed in interface TaskQueue

Returns:

The approximate number of elements in this queue including all items that are visible (available for takes), invisible (in process - not yet completed), and delayed (pending addition to the queue).