Problem with REST client for Queues

[Murty, Sudarshan]

Hi Hazelcast gurus,

I am trying to “offer” a string value into a Queue using a REST client and take() it from within a running java client.

With offer() and take() both in java, it works fine.

 

Exception I get in the blocking java client is:

Exception in thread "main" java.lang.ClassCastException: com.hazelcast.impl.ascii.rest.RestValue cannot be cast to java.lang.String

       at com.mhfi.notification.distribution.NotifTestClient.main(NotifTestClient.java:23)

 

The java client code that is blocking on the queue is:

    public static void main(String[] args) {

                                ClientConfig clientConfig = new ClientConfig();

                                clientConfig.addAddress("127.0.0.1:5701");

                                HazelcastClient client = HazelcastClient.newHazelcastClient(clientConfig);

                                IQueue<String> queue = client.getQueue("MyQueue");

                                System.out.println("Queue size: " + queue.size());

                               

                                try {

                                                for(;;) {

                                                                String qItem = queue.take();

                                                                System.out.println("Queue item: " + qItem);

                                                }

                                } catch (InterruptedException e) {

                                                // TODO Auto-generated catch block

                                                e.printStackTrace();

                                }

    }

 

The server sets up the queue like so:

                IQueue<String> queue = hInst.getQueue("MyQueue");

                queue.offer("Hello");

                queue.offer("World");

                System.out.println("Queue size: " + queue.size());

 

 

I am sending the REST request from chrome using the REST plugin as follows:

URL: http://localhost:5701/hazelcast/rest/queues/MyQueue

Method: POST

Headers: Content-Type: text/plain

Data: “HelloZZZ”

 

 

What am I doing wrong? Your help is really appreciated.

 

regards

- sudarshan

 

S&P Capital IQ Architecture

 

Everything should be made as simple as possible, but not simpler.

-- Albert Einstein

 

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[Murty, Sudarshan]

Here’s another observation – I am using Hazelcast v2.5:

Using REST for both ways works – ie - POST into Queue and GET from queue.

… the docs say use “You can offer a new item into the queue via HTTP POST and take and item from the queue via HTTP DELETE.”

 

If I do a HTTP DELETE, the server throws this exception (all inside Hazelcast) :

WARNING: [10.143.3.178]:5701 [dev] String index out of range: -24

java.lang.StringIndexOutOfBoundsException: String index out of range: -24

       at java.lang.String.substring(String.java:1911)

       at com.hazelcast.impl.ascii.rest.HttpDeleteCommandProcessor.handle(HttpDeleteCommandProcessor.java:40)

       at com.hazelcast.impl.ascii.rest.HttpDeleteCommandProcessor.handle(HttpDeleteCommandProcessor.java:22)

       at com.hazelcast.impl.ascii.TextCommandServiceImpl$CommandExecutor.run(TextCommandServiceImpl.java:198)

       at com.hazelcast.impl.executor.ParallelExecutorService$ParallelExecutorImpl$ExecutionSegment.run(ParallelExecutorService.java:212)

       at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)

       at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)

       at java.lang.Thread.run(Thread.java:722)

       at com.hazelcast.impl.ExecutorThreadFactory$1.run(ExecutorThreadFactory.java:38)

[Murty, Sudarshan]

Ok, I solved the original problem re: the ClassCastException this way, after getting a cue from googlegroups.

 

       IQueue<RestValue> qRest = client.getQueue("MyQueue");

       RestValue restValue = qRest.take();

       byte[] postedBytes = restValue.getValue();

       System.out.println(new String(postedBytes, "UTF-8"));

 

But the same queue “MyQueue” cannot now be used for both java clients as well as REST clients.

Now the java client throws the ClasscastException L

 

Is there a better way to do this w/o resorting to instanceOf or similar ?

[Mustafa Sancar Koyunlu]

Hi Sudarshan,

About your original problem, there is no other way right now. Your workaround is OK.

The second problem:

You are getting that exception because delete waits for timeout value(in seconds). 

Correct syntax

http://localhost:5701/hazelcast/rest/queues/MyQueue/2

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