Speedo: an implementation of JDO compliant personality on top of JORM generic I/O sub-system.

Copyright (C) 2001-2004 France Telecom R&D

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

Overview

The Speedo product is a JDO implementation based on several objectweb frameworks: Jorm, Medor, Perseus. Speedo is built using the component model Fractal of Objectweb.

Architecture

Before trying to understand the Speedo architecture aknownledges on Jorm, Medor, Perseus and Fractal are required.

The following picture represents the Speedo component which is instanciated:

The org.objectweb.speedo.Speedo class is in charge of creating and initializing a Speedo component in respect with the user properties specified on the JDOHelper.

This package contains a web application base on JDO facilities ; This application is named "J2EEDO". It's a sample of a Web application to be depoyed on a J2EE server.

Package description

This package contains two JUnit test case classes:

• TestJ2eedoApplication allows to test the application in standalone mode directly form JUnit.
• TestJ2eedoJ2ee allows to test the application deployed on a J2EE application server form JUnit.

The J2EEDO application

Introduction

It's a sample of a Web application to be depoyed on a J2EE server.

Application's description

J2EEDO Application implementation

Database modele overview

This application implements the following data model built on 4 tables: Department Employee Address Project

Packages content

The application is made of 7 main java packages:

• org.objectweb.speedo.j2eedo: contains two JUnit test case classes:

  • TestJ2eedoApplication allows to test the application in standalone mode directly form JUnit.
  • TestJ2eedoJ2ee allows to test the application deployed on a J2EE application server form JUnit.

• org.objectweb.speedo.j2eedo.bo: contains all business object class handling the data modele.

  • DatabaseImpl is the main class and implements all defined actions. This class defines 3 static vectors used to store known department, employee and project. Those 3 local vectors must decrease the number of access to database object, they are also called the static polls.
    Remark:Those pool contents are update by the Synchronization class PollsSynchronizations each time a department, an employee or a project is added or removed. This task is performed while the current action is commited (when a transaction is required) otherwise, this treatment is done when the current Persistence Manager is closed.
  • PollsSynchronizations defines the Synchronization Object used to update DatabaseImpl's static polls content.
  • DepartmentFactory, EmployeeFactory and ProjectFactory classes define the different treatment on Department, Employee and Project

• org.objectweb.speedo.j2eedo.common: contains is a tool box, it contains all common class used by the application.

  • HTTPTools provides with a way to get the response throught an HTTP call,
  • PMHolder stores Persistence Manager Factory and handles the get, close Persistence Manager. The close method implement the synchronization of the static pools.
  • TraceTime and TraceTimeElement are used to calculate the elapse time for processes

• org.objectweb.speedo.j2eedo.database: contains all classes to be enhanced used to access to the database content.

  • DatabaseObjectInterface define an interface to access any object Id.
  • Department, Employee and Project classes define have to be enhanced access to Department, Employee and Project
  • Address class have also to be enhanced, this class is only used by the class Employee.

• org.objectweb.speedo.j2eedo.ejb: contains is the EJB session definition.

  • StoreServices implements the interface to perform DatabaseImpl action in a Session Container.

• org.objectweb.speedo.j2eedo.test: contains all test class use to highlight errors or behaviours.

  • MainLauncher is used for basic test implementation. The developper needs to create a new class extended of this class and writes its own test method doTest().
  • BasicTest executes 20 times all DatabaseImpl actions.
  • ShowConcurrencyErrors allows to highlight some conccurent access deadlocks and issues.

• org.objectweb.speedo.j2eedo.web: contains the servlets classes' definition.

  • MainServlet executes current request:
    • Gets the Persistence manager when required (false by default),
    • Starts a local transaction when requested (false by default),
    • Calls the dedicated action directly or through a Session Bean Container (direct call by default),
    • Close the PM when initialized at the servlet level.
  • ApplicationServlet is an extended of the former servlet MainServlet. This class implements the two methods used to execute the resquest through a Session Bean or directly from the DataBaseImpl class.

Description

This package contains all business object class handling the data modele.

• DatabaseImpl is the main class and implements all defined actions. This class defines 3 static vectors used to store known department, employee and project. Those 3 local vectors must decrease the number of access to database object, they are also called the static polls.
  Remark:Those pool contents are update by the Synchronization class PollsSynchronizations each time a department, an employee or a project is added or removed. This task is performed while the current action is commited (when a transaction is required) otherwise, this treatment is done when the current Persistence Manager is closed.
• PollsSynchronizations defines the Synchronization Object used to update DatabaseImpl's static polls content.
• DepartmentFactory, EmployeeFactory and ProjectFactory classes define the different treatment on Department, Employee and Project

Description

This package contains is a tool box, it contains all common class used by the application.

• HTTPTools provides with a way to get the response throught an HTTP call,
• PMHolder stores Persistence Manager Factory and handles the get, close Persistence Manager. The close method implement the synchronization of the static pools.
• TraceTime and TraceTimeElement are used to calculate the elapse time for processes

Description

This package contains all classes to be enhanced used to access to the database content.

• DatabaseObjectInterface define an interface to access any object Id.
• Department, Employee and Project classes define have to be enhanced access to Department, Employee and Project
• Address class have also to be enhanced, this class is only used by the class Employee.

Description

This package contains is the EJB session definition.

• StoreServices implements the interface to perform DatabaseImpl action in a Session Container.

Description

This package contains the servlets classes' definition.

• MainServlet is an abstract class. It executes current request:
  • Gets the Persistence manager when required (false by default),
  • Starts a local transaction when requested (false by default),
  • Calls the dedicated action directly or through a Session Bean Container (direct call by default),
  • Close the PM when initialized at the servlet level.
• ApplicationServlet is an extended of the former servlet MainServlet. This class implements the two methods used to execute the resquest through a Session Bean or directly from the DataBaseImpl class.

A Jorm mapper for speedo is a composite component. Here is a picture representing this composite:

This composite contains 4 components:

• The JormStorageManage component is in charge of managing the I/O with the data support (read, write) and the identifier management (export, unexport, bind)
• The JormFactory is in charge of the initialisation of the persistent classes and the loading of Jorm meta information.
• The Mapper is in charge of referencing persistent classes initialized and the connection allocation. The connections permit to access the data support.
• The Pool is used by the Mapper in order to pool physical connection, when it is not already done by the connection provider.

Implementation of several naming.

The supported naming are:

• UserIdSingle: the identifier is based on a single persistent field,
• UserIdComposite: the identifier is based on a set of persistent field,
• RdbSequence: the identifier is based on a single persistent field which values are choosen by a sequence on a relational database.
• LongId: the identifier is based on single long composed of two parts (class idendifier (high bits), instance identifier (low bits)). The value are choosen by the implementation (Jorm facilities) through persistent generators.
• OLongId: the identifier is based on single java.lang.Long composed of two parts (class idendifier (high bits), instance identifier (low bits)). The value are choosen by the implementation (Jorm facilities) through persistent generators.
• PolymorphId: the identifier is based on couple of long (class idendifier, instance identifier). The value are choosen by the implementation (Jorm facilities).