java nio的优先选择器？

Question

I'm working with Amazon SQS queues, and I want to have two queues, let's say one with high priority tasks, and other with low priority tasks.

I want to create a setup where my app always consumes all high priority tasks first before it starts consuming the low priority ones (starvation is no problem in my case).

My first ideia was to have two cosumers, one for each queue, getting the messages from each queue and putting them into a java.util.PriorityQueue, but I wanted to avoid the inserting (and sorting/blocking/synchronizing) cost, because there will a high volume of messages.

Then, I thought about usign java.nio, but I couldn't figure out if this is possible.

My idea was to still have the two consumers, but now they put their tasks in two nio.buffers (high priority buffer, low priority buffer), these buffers are bound to nio.channels (high p. channel, low p. channel), and then a selector should somehow consume first from high priority channel if possible, before consuming from low priority channel.

I haven't found a way to configure this selection order. Is this possible?

Any other alternative?

thanks in advance.

Answer 1

Amazon SQS provide a function to query unread message size.

When you want get message,query unread message size from high priority SQS,if the size > 0,get message from high priority,else get message from low priority sqs.

AWSQSClient.getQueueUnreadSize(String queue_name);

How's this?