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

Methods

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()
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 names 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

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 names 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 java.util.Iterator<java.util.Collection<com.blacklocus.qs.Message>>

remove

public void remove()

Specified by:

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

hasNext

public boolean hasNext()

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