ActionScript 3: Serializing Classes using registerClassAlias

In previous article “Component and SharedObject Example” we’ve seen how to store simple variables in Local Shared Object. But, what if you want to store a custom class objects in Shared Object?

You can use flash.net. registerClassAlias() to do so. This method is similar to old Object.registerClass() (Removed in AS3).

Shared Objects are stored in AMF (Action Message Format) format. When you try to save class object in Shared Object, it will be stored as normal object. It will not have any reference to the class. Thus to save the information about the class, one has to use registerClassAlias class. This is also called as Serializing Classes.

Apart from SharedObject, this class can be used for LocalConnection, ByteArray , NetConnection and NetStream.

Here is a simple example of using registerClassAlias. In this example, object of Person class is stored in Shared Object. This example also demonstrates use of AS3 components (Label, ComboBox, Button, InputText).

Below is the code:

Class Person:

package {
public class Person {
private var _name:String;
private var _age:uint;
private var _gender:String;
public function Person() {
this._name = "";
this._age = undefined;
this._gender = "";
}
public function get name():String {
return this._name;
}
public function set name(name:String):void {
this._name = name;
}
public function get age():uint {
return this._age;
}
public function set age(age:uint):void {
this._age = age;
}
public function get gender():String {
return this._gender;
}
public function set gender(gender:String):void {
this._gender = gender;
}
public function getPerson():String {
return "Name: " + this._name + " Age: " + this._age + " Gender: " + this._gender;
}
}
}

Class soExample:

package {
import fl.controls.Button;
import fl.controls.Label;
import fl.controls.TextInput;
import fl.controls.NumericStepper;
import fl.controls.ComboBox;
import fl.data.DataProvider;
import flash.display.Sprite;
import flash.events.MouseEvent;
import flash.net.SharedObject;
import flash.net.registerClassAlias;
public class soExample extends Sprite {
private var getData_btn:Button;
private var setData_btn:Button;
private var delData_btn:Button;
private var titleLbl:Label;
private var statLbl:Label;
private var nameLbl:Label;
private var ageLbl:Label;
private var genderLbl:Label;
private var name_txt:TextInput;
private var ageNS:NumericStepper;
private var genderCB:ComboBox;
private var _mc:Sprite;
private var mySO:SharedObject;
private var tushar:Person;
public function soExample(_mc:Sprite) {
registerClassAlias(”PersonAlias”, Person);
this._mc = _mc;
updateUI();
updateDisplay();
getSO();
}
private function updateUI():void {
getData_btn = createButton("Get Shared Object", 150, 10, 160, "get_btn");
setData_btn = createButton("Store Shared Object", 150, 10, 190, "set_btn");
delData_btn = createButton("Delete Shared Object", 150, 10, 220, "del_btn");
titleLbl = createLabel("<b>AS3 - Shared Object Example</b>", 200, 10, 10);
statLbl = createLabel("", 400, 10, 250);
nameLbl = createLabel("Name: ", 100, 10, 50);
ageLbl = createLabel("Age: ", 100, 10, 80);
genderLbl = createLabel("Gender: ", 100, 10, 110);
name_txt = createTextInput(200, 60, 50);
ageNS = createNumericStepper(25, 50, 22, 60, 80);
genderCB = createComboBox(100, 22, 60, 110, new DataProvider(["Male", "Female"]));
}
private function updateDisplay():void {
_mc.addChild(titleLbl);
_mc.addChild(nameLbl);
_mc.addChild(ageLbl);
_mc.addChild(genderLbl);
_mc.addChild(statLbl);
_mc.addChild(getData_btn);
_mc.addChild(setData_btn);
_mc.addChild(delData_btn);
_mc.addChild(ageNS);
_mc.addChild(name_txt);
_mc.addChild(genderCB);
}
private function createButton(lbl:String, w:uint, x:uint, y:uint, nme:String):Button {
var BTN:Button = new Button();
BTN.label = lbl;
BTN.width = w;
BTN.move(x, y);
BTN.name = nme;
BTN.addEventListener(MouseEvent.CLICK, clickHandler);
return BTN;
}
private function createLabel(lbl:String, w:uint, x:uint, y:uint):Label {
var LBL:Label = new Label();
LBL.htmlText = lbl;
LBL.width = w;
LBL.move(x, y);
return LBL;
}
private function createTextInput(w:uint, x:uint, y:uint):TextInput {
var TI:TextInput = new TextInput();
TI.htmlText = "";
TI.width = w;
TI.move(x, y);
return TI;
}
private function createNumericStepper(defaultVal:uint, w:uint, h:uint, x:uint, y:uint):NumericStepper {
var NS:NumericStepper = new NumericStepper();
NS.move(x, y);
NS.setSize(w, h);
NS.minimum = 1;
NS.maximum = 150;
NS.stepSize = 1;
NS.value = defaultVal;
return NS;
}
private function createComboBox(w:uint, h:uint, x:uint, y:uint, _data:DataProvider):ComboBox {
var CB:ComboBox = new ComboBox();
CB.move(x, y);
CB.setSize(w, h);
CB.dataProvider = _data;
return CB;
}
private function clickHandler(event:MouseEvent):void {
respondToMouseEvent(event.target.name);
}
private function respondToMouseEvent(nme:String):void {
switch (nme) {
case "get_btn":
getSO();
break;
case "set_btn":
setSO();
break;
case "del_btn":
deleteSO();
break;
}
}
private function getSO():void {
name_txt.text = "";
mySO = SharedObject.getLocal(”person”);
if (mySO.size == 0) {
// Shared object doesn’t exist.
statLbl.htmlText = "Status: SharedObject not found.";
name_txt.text = "";
ageNS.value = 25;
genderCB.selectedIndex = 0;
} else {
name_txt.text = mySO.data.person.name;
ageNS.value = mySO.data.person.age;
if(mySO.data.person.gender == "Female"){
genderCB.selectedIndex = 1;
}
statLbl.htmlText = "Status: SharedObject value is - <b>"+mySO.data.person.getPerson()+"</b>";
}
}
private function setSO():void {
if (name_txt.text != "") {
tushar = createPerson(name_txt.text, ageNS.value, genderCB.selectedItem.data);
mySO.data.person = tushar;
mySO.flush();
getSO();
} else {
statLbl.htmlText = "Status: <b>Name</b> missing.";
}
}
private function deleteSO():void {
mySO.clear();
getSO();
}
private function createPerson(name:String, age:uint, gender:String):Person {
var tmpPerson = new Person();
tmpPerson.name = name;
tmpPerson.age = age;
tmpPerson.gender = gender;
return tmpPerson;
}
}
}

Now, create object of soExample and pass movieclip reference (in which all the components will be added at runtime) as parameter:

var mySoExample:soExample = new soExample(this);

Note: Be sure to add “Button”, “Label”, ”ComboBox”, ”NumericStepper” & “TextInput” components to the library of that movie.

Source:  AS3 Serializing Example (Zip file included)