RAGHAVA NAIDU

What is Channel

Channels are Client side objects that encapsulate the connection behaviour between flex components and blazeds server.

What Channel will do

• Channel formats and translates the message into a network specific form.


• Channel communicates with corresponding end points on the BlazeDS server.


• Channels impose an order to the flow of messages sent to the server and the order of corresponding responses to ensure that the interaction between the client and server occurs in a consistent and predictable fashion.

Where to configure channel

We define channels and endpoints in services-config.xml file

How to configure channel
<channels>
...
<channel-definition id="my-amf"
type="mx.messaging.channels.AMFChannel">
<endpoint url="http://servername:port/myapp/messagebroker/amf"
type="flex.messaging.endpoints.AMFEndpoint"/>
</channel-definition>
</channels>

When I am working with Maven and Flex with FlexMojos I come across the below error.

It is a good practice to use int in place of Number if the type int can able to satisfy your requirements. First we will see the difference between int,uint and Number.

• uint - values ranging from 0 to 4,294,967,29 (positive numbers)
• int - values ranging from -2,147,483,648 to 2,147,483,647
• Number -can have values ranging far beyond int and uint and can include a decimal point

var l:int = myArray.length;
for(var i:Number=0; i<l;i++>
{
 ............
}

var l:int = myArray.length;
for(var i:int=0; i<l;i++>
{
 ............
}

Flex 4 introduced new collection ArrayList. ArrayList and ArrayCollection both are used to manipulate and store listdata. The key differences between ArrayList and ArrayCollection are

• ArrayList is lighter version of ArrayCollection
• With ArrayCollection we can sort and filter listdata and it is not possible with ArrayList

Flash Player and AIR use a technique called garbage collection to clear objects from memory that are no longer in use. An object is considered no longer in use if no references to it exist. The garbage collector disregards weak references, which means that a listener function that has only a weak reference pointing to it is eligible for garbage collection.

In Action Script, we use addEventListener method to attach an event listener. It includes the bellow parameters:

eventName:String,
listener:Object,
useCapture:Boolean=false,
priority:Integer=0,
useWeakReference:Boolean=false

The useWeakReference parameter allows us to specify whether the reference to the listener function is weak or normal. Setting this parameter to true allows us to avoid situations in which listener functions persist in memory even
though they are no longer needed.

For example:

btn.addEventListener(MouseEvent.CLICK, clickHandler,false,0,true);