Ride your RIA Vehicle using Google App Engine in a Cloud

Know your Engine:

GAE is running Java 6. However, there are  number of limitations that have been imposed to constrain Java to fit the GAE model. GAE Java is based on the Java 2.4 Servlet API:

• Once a request is sent to the client no further processing can be done. This includes data streaming.
• A request will be terminated if it has taken around 30 seconds without completing. At this point an exception is thrown. If not caught a 500 error is returned to the user.

Moving up the stack are several sandbox restrictions:

• Applications can not write to the file system and must use the App Engine datastore instead.
• Applications may not open sockets
• Applications can not create their own threads or use related utilities such as timer.

java.lang.System has been restricted as follows:

• exit(), gc(), runFinalization(), and runFinalizersOnExit() do nothing.
• JNI access is not allowed.

Choose your RIA Vehicle(FLEX/BLAZEDS/JAVA):

• Eclipse – http://www.eclipse.org/galileo/ (FREE)
• Google App Engine Developer Account – http://appengine.google.com/ (FREE)
• Install the Google App Engine Java plug-in for Eclipse – http://code.google.com/appengine/docs/java/tools/eclipse.html (FREE)
• Flex Builder plug-in for Eclipse – http://www.adobe.com/products/flex/features/flex_builder/ ($$$)
• The BlazeDS Binary Distribution- http://opensource.adobe.com/wiki/display/blazeds/Release+Builds (FREE)

Aravind Kopparthi.