ADOBE® FLEX® 3: PROGRAMMING ACTIONSCRIPT™ 3.0

ADOBE FLEX 3

Developer Guide

475

Save the document to your hard disk as SimpleServer.java and compile it using a Java compiler, which creates a Java

class file named SimpleServer.class.

You can start the XMLSocket server by opening a command prompt and typing

java SimpleServer. The

SimpleServer.class file can be located anywhere on your local computer or network; it doesn’t need to be placed in

the root directory of your web server.

If you’re unable to start the server because the files are not located within the Java classpath, try starting the server with

java -classpath . SimpleServer.

To connect to the XMLSocket from your ActionScript application, you need to create a new instance of the

XMLSocket class, and call the

XMLSocket.connect() method while passing a host name and port number, as

follows:

var xmlsock:XMLSocket = new XMLSocket();

xmlsock.connect("127.0.0.1", 8080);

A securityError (flash.events.SecurityErrorEvent) event occurs if a call to XMLSocket.connect() attempts to

connect either to a server outside the caller’s security sandbox or to a port lower than 1024.

Whenever you receive data from the server, the

data event (flash.events.DataEvent.DATA) is dispatched:

xmlsock.addEventListener(DataEvent.DATA, onData);

private function onData(event:DataEvent):void

{

trace("[" + event.type + "] " + event.data);

}

To send data to the XMLSocket server, you use the XMLSocket.send() method and pass an XML object or string.

Flash Player converts the supplied parameter to a String object and sends the content to the XMLSocket server

followed by a zero (0) byte:

xmlsock.send(xmlFormattedData);

The XMLSocket.send() method does not return a value that indicates whether the data was successfully trans-

mitted. If an error occurred while trying to send data, an IOError error is thrown.

Each message you send to the XML socket server must be terminated by a newline (

\n) character.

Storing local data

A shared object, sometimes referred to as a “Flash cookie,” is a data file that can be created on your computer by the

sites that you visit. Shared objects are most often used to enhance your web-browsing experience—for example, by

allowing you to personalize the look and feel of a website that you frequently visit. Shared objects, by themselves,

can’t do anything to or with the data on your computer. More important, shared objects can never access or

remember your e-mail address or other personal information—unless you willingly provide such information.

New shared object instances can be created using the static

SharedObject.getLocal() or

SharedObject.getRemote() methods. The getLocal() method attempts to load a locally persistent shared object

that is available only to the current client, whereas the

getRemote() method attempts to load a remote shared object

that can be shared across multiple clients by means of a server, such as Flash Media Server. If the local or remote

shared object does not exist, the

getLocal() and getRemote() methods will create a new SharedObject instance.

The following code attempts to load a local shared object named

test. If this shared object doesn’t exist, a new

shared object with this name will be created.