Java EE considerations

As you prepare to integrate WebSphere® eXtreme Scale in a Java™ Platform, Enterprise Edition environment, consider certain items, such as versions, configuration options, requirements and limitations, and application deployment and management.

Running eXtreme Scale applications in a Java EE environment

A Java EE application can connect to a remote eXtreme Scale application. Additionally, the WebSphere Application Server environment supports starting an eXtreme Scale server when an application starts in the application server.

If you use an XML file to create an ObjectGrid instance, and the XML file is in the module of the enterprise archive (EAR) file, access the file by using the getClass().getClassLoader().getResource("META-INF/objGrid.xml") method to obtain a URL object to use to create an ObjectGrid instance. Substitute the name of the XML file that you are using in the method call.

You can use startup beans for an application to bootstrap an ObjectGrid instance when the application starts, and to destroy the instance when the application stops. A startup bean is a stateless session bean with a com.ibm.websphere.startupservice.AppStartUpHome remote location and a com.ibm.websphere.startupservice.AppStartUp remote interface. The remote interface has two methods: the start method and the stop method. Use the start method to bootstrap the instance, and use the stop method to destroy the instance. The application uses the ObjectGridManager.getObjectGrid method to maintain a reference to the instance. See Interacting with an ObjectGrid using the ObjectGridManager interface for more information.

Using class loaders

When application modules that use different class loaders share a single ObjectGrid instance in a Java EE application, verify the objects that are stored in eXtreme Scale and the plug-ins for the product are in a common loader in the application.

Managing the life cycle of ObjectGrid instances in a servlet

To manage the life cycle of an ObjectGrid instance in a servlet, you can use the init method to create the instance and the destroy method to remove the instance. If the instance is cached, it is retrieved and manipulated in the servlet code. See Interacting with an ObjectGrid using the ObjectGridManager interface for more information.