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Server-Side Communication ActionScript 25

If all instances of the Client object (each client in an application) require the same methods or

properties, you can add those methods and properties to the class itself instead of adding them to

each instance of a class. This process is called extending a class. You can extend any server-side or

client-side ActionScript class. To extend a class, instead of defining methods inside the

constructor function of the class or assigning them to individual instances of the class, you assign

methods to the

prototype property of the constructor function of the class. When you assign

methods and properties to the

prototype property, the methods are automatically available to all

instances of the class.

Extending a class lets you define the methods of a class separately, which makes them easier to

read in a script. And more importantly, it is more efficient to add methods to

prototype,

otherwise the methods are re-interpreted each time an instance is created.

The following code shows how to assign methods and properties to an instance of a class. During

application.connect, a client instance clientObj is passed to the server-side script as a

parameter. You can then assign a property and method to the client instance:

application.onConnect = function(clientObj){

}

clientObj.birthday = myBDay;

clientObj.calculateDaysUntilBirthday = function(){

// insert code here

}

The above example works, but must be executed every time a client connects. If you want the

same methods and properties to be available to all clients in the

application.clients array

without defining them every time, you must assign them to the prototype property of the Client

object There are two steps to extending a built-in class using the

prototype method. You can

write the steps in any order in your script. The following example extends the built-in Client

object, so the first step is to write the function that you will assign to the

prototype property:

// first step: write the functions

function Client_getWritePermission(){

// "writeAccess" property is already built-in to the client class

return this.writeAccess;

}

function Client_createUniqueID(){

var ipStr = this.ip;

// "ip" property is already built-in to the client class

var uniqueID = "re123mn"

// you would need to write code in the above line

// that creates a unique ID for each client instance

return uniqueID;

}

// second step: assign prototype methods to the functions

Client.prototype.getWritePermission = Client_getWritePermission;

Client.prototype.createUniqueID = Client_createFriendlyUniqueID;

// a good naming convention is to start all class method

// names with the name of the class, followed by an underscore

You can also add properties to prototype, as shown in the following example:

Client.prototype.company = "Macromedia";

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