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In short, we took an A la Carte approach, choosing only those technologies we actually needed that fullfilled our requirements, and adopting an *emerging post-EJB consensus* favoring a lightweight container to provide only those J2EE Enterprise Services we required.
Under this definition, a continaer could be anything from a full-blown J2EE Application Server to Apache Tomcat, depending on the services required of the container.
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For the GLAST Framework, a lightweight container had to provide the following services:
Service | Description | All Containers | Lightweight Containers |
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Lifecycle management | Control lifecycle of application objects running within it (for example, clean initialization, startup and shutdown). |
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Lookup | Obtain references to managed objects; create objects/services on demand. |
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Configuration | Externalize configuration from code into simple configuration files. |
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Dependency resolution | Manage relationships among managed objects (for example, configuring beans by calling setters, or automatically calling constructors with managed beans). |
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Transaction management | Externalize transaction management from code into configuration files (i.e. declarative transactions). |
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Object pooling | The obvious example are database connections. |
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Expose remote services | Not just SOAP based web services; there are other, simpler wire protocols. |
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Consume remote services | Provide transparent access to remote objects running outside the container. |
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Non-invasive | Run existing legacy code as-is in the container. Code should run the same both inside and outside the container |
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Requirement | GINO | RM | Installer | TC | System Tests | Data Access |
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Web configuration/editing |
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Web reports |
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Single Sign-On |
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Persistence (CRUD) |
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Reports (DB Queries) |
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Batch Submission |
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Scheduler |
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Event Notification |
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Automated email |
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