com.blacklocus.qs.aws.sqs

Class AmazonSQSPrioritizedMessageProvider

java.lang.Object

com.blacklocus.qs.aws.sqs.AmazonSQSPrioritizedMessageProvider

All Implemented Interfaces:

com.blacklocus.qs.MessageProvider, com.blacklocus.qs.QueueItemProvider<com.blacklocus.qs.Message>, java.lang.Iterable<java.util.Collection<com.blacklocus.qs.Message>>, java.util.Iterator<java.util.Collection<com.blacklocus.qs.Message>>

public class AmazonSQSPrioritizedMessageProvider
extends java.lang.Object
implements com.blacklocus.qs.MessageProvider

Provide a prefix-based SQS priority queue. Each queue matching a prefix is drained in lexicographically sorted order. New queues that are created that match the given prefix are automatically picked up and processed in the same priority order based on a configurable interval. Note that this MessageProvider iterator implementation is not thread-safe. Calls to next() are not intended to be called outside of a single queue reading thread. You will need to externally synchronize calls to next() if you intend to access it in more than one thread. The delete() method is thread-safe.

Field Summary

Fields

Modifier and Type	Field and Description
static java.util.Comparator<java.lang.String>	DEFAULT_QUEUE_COMPARATOR

Constructor Summary

Constructors

Constructor and Description
AmazonSQSPrioritizedMessageProvider(com.amazonaws.services.sqs.AmazonSQS sqs, java.lang.String queuePrefix, long updateIntervalMs) Create a new MessageProvider instance.

Method Summary

Modifier and Type	Method and Description
long	currentNanoTime() A wrapper around System.nanoTime() to encapsulate elapsed time handling in one place.
void	delete(com.blacklocus.qs.Message message)
boolean	hasNext()
java.util.Iterator<java.util.Collection<com.blacklocus.qs.Message>>	iterator()
java.util.List<com.blacklocus.qs.Message>	next()
void	remove()
void	setVisibilityTimeout(com.blacklocus.qs.Message message, java.lang.Integer visibilityTimeoutSeconds)
boolean	shouldUpdateQueues() Returns true if an update to the queues should occur based on the time since this method was last called.
AmazonSQSPrioritizedMessageProvider	withInclude(com.google.common.base.Predicate<java.lang.String> include) Queue URLs that return true for this predicate are included in the list of available queues to be prioritized.
AmazonSQSPrioritizedMessageProvider	withQueueComparator(java.util.Comparator<java.lang.String> queueComparator) This comparator controls the sort order of the returned queues.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

forEachRemaining

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Detail

DEFAULT_QUEUE_COMPARATOR

public static final java.util.Comparator<java.lang.String> DEFAULT_QUEUE_COMPARATOR

Constructor Detail

AmazonSQSPrioritizedMessageProvider

public AmazonSQSPrioritizedMessageProvider(com.amazonaws.services.sqs.AmazonSQS sqs,
                                           java.lang.String queuePrefix,
                                           long updateIntervalMs)

Create a new MessageProvider instance.

Parameters:

sqs - AmazonSQS instance to use for communicating with AWS

queuePrefix - the prefix to use when searching for queues

updateIntervalMs - time in milliseconds between when new queues should be checked

Method Detail

withInclude

public AmazonSQSPrioritizedMessageProvider withInclude(com.google.common.base.Predicate<java.lang.String> include)

Queue URLs that return true for this predicate are included in the list of available queues to be prioritized. It defaults to including all available queues pulled for a prefix.

Parameters:

include - the predicate to satisfy

Returns:

this instance for chaining

withQueueComparator

public AmazonSQSPrioritizedMessageProvider withQueueComparator(java.util.Comparator<java.lang.String> queueComparator)

This comparator controls the sort order of the returned queues. It defaults to generic String.compareTo().

Parameters:

queueComparator - the custom sorting comparator

Returns:

this instance for chaining

shouldUpdateQueues

public boolean shouldUpdateQueues()

Returns true if an update to the queues should occur based on the time since this method was last called.

Returns:

true if an update to the queues should occur

currentNanoTime

public long currentNanoTime()

A wrapper around System.nanoTime() to encapsulate elapsed time handling in one place.

Returns:

the current value of the running Java Virtual Machine's high-resolution time source, in nanoseconds

next

public java.util.List<com.blacklocus.qs.Message> next()

Specified by:

next in interface com.blacklocus.qs.QueueItemProvider<com.blacklocus.qs.Message>

Specified by:

next in interface java.util.Iterator<java.util.Collection<com.blacklocus.qs.Message>>

remove

public void remove()

Specified by:

remove in interface com.blacklocus.qs.QueueItemProvider<com.blacklocus.qs.Message>

Specified by:

remove in interface java.util.Iterator<java.util.Collection<com.blacklocus.qs.Message>>

hasNext

public boolean hasNext()

Specified by:

hasNext in interface com.blacklocus.qs.QueueItemProvider<com.blacklocus.qs.Message>

Specified by:

hasNext in interface java.util.Iterator<java.util.Collection<com.blacklocus.qs.Message>>

iterator

public java.util.Iterator<java.util.Collection<com.blacklocus.qs.Message>> iterator()

Specified by:

iterator in interface com.blacklocus.qs.QueueItemProvider<com.blacklocus.qs.Message>

Specified by:

iterator in interface java.lang.Iterable<java.util.Collection<com.blacklocus.qs.Message>>

delete

public void delete(com.blacklocus.qs.Message message)

Specified by:

delete in interface com.blacklocus.qs.MessageProvider

setVisibilityTimeout

public void setVisibilityTimeout(com.blacklocus.qs.Message message,
                                 java.lang.Integer visibilityTimeoutSeconds)

Specified by:

setVisibilityTimeout in interface com.blacklocus.qs.MessageProvider