DeferredResult is not polling

Question

I am trying to create a multi user chat environment using the base example from https://github.com/rstoyanchev/spring-mvc-chat

I am not able to find what exactly is wrong with my code. The request is not polling it just keeps on firing request continuously to the server.

Following are my code snipets

web.xml

<servlet>
    <servlet-name>dispatcher</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
    <async-supported>true</async-supported>
</servlet>
<servlet-mapping>
    <servlet-name>dispatcher</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

applicationContext.xml

<mvc:annotation-driven>
    <mvc:async-support default-timeout="30000" />
    <mvc:message-converters register-defaults="false">
        <bean id="jacksonMessageConverter"
            class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter" />
    </mvc:message-converters>
</mvc:annotation-driven>

Controller

@Controller
@RequestMapping("/chat")
public class ChatController
{
    @RequestMapping("messages")
    @ResponseBody
    public DeferredResult<List<String>> getMessages()
    {

        final DeferredResult<List<String>> deferredResult = new DeferredResult<List<String>>(30000l, Collections.emptyList());
        this.chatRequests.put(deferredResult, 0);

        deferredResult.onCompletion(new Runnable()
        {
            @Override
            public void run()
            {
                chatRequests.remove(deferredResult);
            }
        });

        List<String> messages = new ArrayList<String>();
        messages.add("first");
        if (!messages.isEmpty())
        {
            deferredResult.setResult(messages);
        }

        return deferredResult;
    }

}

javascript

function chatModel(){
var started = false;
var that = this;
that.activePollingXhr = ko.observable(null);
function pollForMessages() {
    that.activePollingXhr($.ajax({
        url : contextPath + '/chat/messages',
        type : "GET",
        cache : false,
        success : function(messages) {
            console.log(messages);
        },
        error : function(xhr) {
            if (xhr.statusText != "abort" && xhr.status != 503) {
                console.log('Unable to Connect');
            }
        },
        complete : pollForMessages
    }));
}

Answer 1

Got the issue. if we set results

deferredResult.setResult();

it dont wait so goes into recursive calling.