J2EE For Glast

Introduction

This is a presentation of the proposed adoption of an Enterprise-wide Service Oriented Architecture (SOA) for the GLAST experiment's data processing requirements. This project is composd of two parts, the GRITS Framework and the GRITS Projects that are built upon the framework. This presentation is primarily concerned with the GRITS Framework, which is a lightweight Java based distributed architecture which uses some, but not all, of the technologies from the J2EE specification.

The GRITS Framework is completely in place, and development of the various GRITS Projects within the framework has only recently begun. The first concrete components for the Processing Pipeline (which is one of the GRITS Projects) were recently installed into production.

The outline of this presentation is as follows:

1. The GRITS Framework is introduced, which includes a description of the project's goals, the players involved, current project status and the project's timeline.
2. The GRITS Projects are briefly introduced, with an emphasis on their requirements and use-cases. It is these requirements and use-cases that drove the design and implementaiton of the GRITS Framework.
3. The technologies used by the GRITS Framework are described in some detail.
4. Development tools and methodologies used by the GRITS Framework are described in some detail, as they are the recommended approach for development of GRITS Projects.

GRITS Framework

The GRITS Framework is the infrastructure upon which GRITS Projects are intended to be devloped. The GRITS Framework was born out of a detailed deconstruction of the current, and proposed, GRITS Projects by members of the GLAST Core Team in early 2004. This deconstruction and subsequent analysis identified many common services shared by all GRITS Projects, and an SOA approach to deliver these sercies was unanamously agreed upon.

GRITS Projects

The GLAST Projects are intended to serve the data processing needs of the GLAST collaboration. The current and proposed set of projects, and the platforms they are required to run on, are shown in the following table:

GRITS Common Services

The GRITS Projects share a common set of services, which are listed in the following table.

The bulk of these services are provided out-of-the-box by the GRITS Framework technologies. Those that aren't are provided by the grits commons project.

A shared set of common services was one of the primary reasons for adopting an SOA.

Legacy Systems and Services

Another important reason for adopting an SOA is to leverage and integrate existing back-end systems services. This set of legacy systems and services and the platforms they run on are shown in the following table.

GRITS Framework Goals

The primary goal of the GRITS Framework is to provide the software architecture and infrastructure for the GLAST Core Team to accomplish its mission. Specific goals include:

• Provide a common framework to develop the GRITS Projects and their associated set of common services
• Provide a distributed, cross-platform SOA for GLAST Projects that is simple to develop with and simple to use
• The framework and technologies must have proven to be lightweight, scaleable maintainable, and enjoy wide adoption in the community
• Leverage existing SLAC infrastructure
• Promote team oriented development (as opposed to individual contributors)
• Maximize disparate talents of a small group
  • Programmers
  • Web Developers
  • Occasionally-connected programmer/manager/astronomer
• Utilize talents of JAS group

There are three sets of expected users of the GLAST Framework and GLAST Projects and their timelines.

GRITS Framework Technologies

The GRITS Framework primarily uses open-source software, but also containing commercial components where they make sense.

The primary components are:

1. • The Spring Framework, which is the cornerstone of the GRITS Framework, provides those parts of the J2EE specification that we rejected as either too complicated, too expensive, or otherwise not addressing the project's requirements.
   • Hibernate, a thin wrapper over JDBC which provides the full power of transparent persistence by providing O/R mapping but not trying to hide the underlying relational database.
   • Web servers (IIS on Windows and Apache on Linux) for security-conscious service deployment.
   • ColdFusion MX for web front-end development.
   • Several Jakarta components, primarily Tomcat for service deployment and many of the jakarta commons for

The Databse Schema

Configuring a DataSource

An Example Hibernate Mapping File

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

<hibernate-mapping package="grits.gino.domain">

	<class name="TaskImpl" table="TASK">

		<id name="id" type="long" unsaved-value="null">
			<column name="TASK_PK" />
			<generator class="native">
				<param name="sequence">TASK_SEQ</param>
			</generator>
		</id>

		<property name="name" type="string">
			<column name="TASKNAME" length="30" unique="true"
				not-null="true" />
		</property>

		<property name="datasetBasePath" type="string">
			<column name="BASEFILEPATH" length="200" not-null="false" />
		</property>

		<property name="runLogPath" type="string">
			<column name="RUNLOGFILEPATH" length="200" not-null="true" />
		</property>

		<many-to-one name="type">
			<column name="TASKTYPE_FK" not-null="true" />
		</many-to-one>

		<set name="taskProcessSortedSet" inverse="true"
			cascade="all-delete-orphan" sort="natural" order-by="SEQUENCE asc">

			<key column="TASK_FK" />
			<one-to-many class="TaskProcessImpl" />
		</set>

		<set name="datasetSetInternal" inverse="true"
			cascade="all-delete-orphan">

			<key column="TASK_FK" />
			<one-to-many class="DatasetImpl" />
		</set>

	</class>

</hibernate-mapping>