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6.20.  < a4j:queue >

The <a4j:queue> component creates queues that other components can reference and use.

Table 6.39. a4j : queue attributes

Attribute NameDescription
bindingThe attribute takes a value-binding expression for a component property of a backing bean
disabledIf "true", disable this component on page.
idEvery component may have a unique id that is automatically created if omitted
ignoreDupResponsesAttribute allows to ignore an Ajax Response produced by a request if the newest 'similar' request is in a queue already. ignoreDupResponses="true" does not cancel the request while it is processed on the server, but just allows to avoid unnecessary updates on the client side if the response isn't actual now
nameThe optional name of this component
onbeforedomupdateJavaScript code for call before DOM has been updated on client side
oncompleteJavaScript code for call after request completed on client side
onerrorHTML: a script expression; event fires whenever an JavaScript error occurs
onsizeexceededA script expression; a size is exceed
onsubmitJavaScript code for call before submission of ajax event
requestDelayAttribute defines the time (in ms.) that the request will be wait in the queue before it is ready to send. When the delay time is over, the request will be sent to the server or removed if the newest 'similar' request is in a queue already
sizeDefines the number of items allowed in the queue at one time.
sizeExceededBehaviorDefines the strategies of the queue's behavior if the number of the requests waiting in the queue is exceeded. There are four strategies: dropNext (by default), dropNew, fireNext , fireNew.
timeoutResponse waiting time on a particular request. If a response is not received during this time, the request is aborted

Table 6.40. Component identification parameters

NameValue
component-familyorg.ajax4jsf.Queue
component-classorg.ajax4jsf.component.html.HtmlQueue
renderer-typeorg.ajax4jsf.QueueRenderer
tag-classorg.ajax4jsf.taglib.html.jsp.QueueTag

Here is the simplest way for a component creation on a page.

Example:


<h:form>
       <a4j:queue name="fooQueue" ... />
</h:form>

Example:

import org.ajax4jsf.component.html.HtmlQueue;            

...
HtmlQueue myQueue = new HtmlQueue();

By means of the <a4j:queue> component a user can create several types of queues associated with it.

The "size" attribute help you to set the number of items allowed in the queue at one time.

Here you can see the example of <a4j:queue> usage and sources for the given example.