Macromedia flash media server 2-developing media applications User Manual

52

Using Media Classes

The SharedObject class

Shared objects can be used for a wide number of purposes, and can be designed and used in a 
number of ways. This section provides some items to consider as you begin using shared 
objects in your applications. 

About synchronizing shared objects

Before attempting to work with a remote shared object, you should first check that the 

SharedObject.connect()

 method returned a value of 

true

, indicating a successful 

connection, and then wait until you receive a result from the function you have assigned to 
the 

SharedObject.onSync

 handler. If you fail to do so, any changes you make to the object 

locally—before 

SharedObject.onSync

 is invoked—may be lost.

The 

SharedObject.onSync

 handler is invoked when any of the 

SharedObject.data

 

properties of the remote shared object are changed. The handler is also invoked the first time 
a client uses the 

SharedObject.getRemote()

 method to connect to a remote shared object 

that is persistent locally or on the server. In the latter case, all the object properties are set to 
empty strings, and 

SharedObject.onSync

 is invoked with the value of the 

code

 property set 

to 

"clear"

. Then 

SharedObject.onSync

 is invoked again, this time with the value of 

code

 

set to 

"change"

, and the properties of the client’s instance of the remote shared object will be 

set to match those on the server. 

If you are having problems understanding how your shared object is behaving, it helps to 
place some debug code in your 

SharedObject.onSync

 handler, as in the following example:

my_so.onSync = function(list) {

for (var k in list) {

trace("name = " + list[k].name + ", event = " + list[k].code);

}
// do whatever else you want to do here

}

Using shared object slots effectively

The decision to encapsulate shared object data in a single slot (

SharedObject.data

 property) 

or to spread it among multiple slots depends partially on how your application posts changes 
to the object. For example, if your application needs to send an entire array of strings to all of 
the connected clients at specific intervals, you can store the entire array in a single slot.