DM203 Enterprise Java Beans in Adaptive Sever Enterprise - PowerPoint PPT Presentation

Title: DM203 Enterprise Java Beans in Adaptive Sever Enterprise


1
DM203Enterprise Java Beans in Adaptive Sever
Enterprise
Girish Vaitheeswaran Senior Software
Engineer Database Server Technologies girish_at_sybas
e.com
2
Contents

• An Introduction to EJB
• To EJB or not to EJB
• EJB and ASE whats the nexus
• ASE-EJB Architecture
• ASE-EJB Architecture Components
• ASE-EJB Interface
• Developing and Deploying EJB Components

3
Contents

• High Availability
• Unified Login and Role Mapping
• Conclusions
• References
• Questions

4
What is EJB

• Enterprise Java Beans is a standard server side
  component model for the development and
  deployment of distributed enterprise-level
  applications
• Applications written using the EJB architecture
  are scalable, transactional and multi-user secure
• Write once run anywhere
• Writing business logic in java helps improve
  flexibility and ease of writing components
• Code reuse helps rapid application development

5
What is EJB

• Types of EJBs
• Session bean
• An extension of the client application
  responsible for managing processes or tasks.
• It models interactions but does not have any
  persistent state.
• Example A Travel agent bean making a
  reservation for a cruise.

6
What is EJB

• Types of EJBs (cont)
• 2 types of Session beans
• Stateful session bean - They maintain in -memory
  state information of the conversation between the
  client and the bean
• Stateless session bean - Do not maintain
  conversational state hence is more scalable

7
What is EJB

• Types of EJBs (cont)
• Entity bean
• These represent persistent records in some kind
  of database.
• An entity bean has a persistent state.
• Example A customer, a piece of equipment, an
  item in inventory etc

8
EJB and ASE whats the nexus

• EJB Component development task list
• JDBC connection to a data source
• Standard DML operations such as selects, updates,
  inserts and deletes
• Develop and Deploy using an IDE or a Systems
  Management interface for EJB Servers
• Typically need to have a 3 tier setup with an EJB
  Server in the middle tier

9
EJB and ASE whats the nexus

• What does all this imply
• Connections to the database over the network are
  known to be expensive
• Data sets being transferred over the network can
  be large and can cause significant latency
• Security can be a factor since data is being
  transferred over the wire
• Knowledge of new development and deployment tools
  for component development, deployment and
  management are required
• Managing the complexities of a 3 tier
  architecture

10
EJB and ASE whats the nexus

• Problem definition
• Performance Impact
• Security Impact
• Lack of Flexibility

11
EJB and ASE whats the nexus

• EJB Support in ASE is the solution
• High Performance Communication
• High Speed Communication through ASEs shared
  memory
• Secure data transfer
• No data transfer over the wire
• Complete Flexibility
• EJBs can be deployed either in the middle tier
  or in the database tier

12
EJB and ASE whats the nexus

• EJB Support in ASE is the solution
• Consolidation approach where the EJB Server can
  be managed as part of the Database Server
  Management using a single interface like Sybase
  Central plug-in for ASE
• Simple, easy to use T-SQL interface for
  performing various system management tasks

13
3 Tier Architecture
Engine 3
JDBC request
EJB Request
Engine 2
Engine 1
Data Set
Response
Client
EJB Server
Database Server
14
2 Tier Architecture
EJB Server
Engine 3
Engine 2
EJB Request
Engine 1
Response
Client
Database Server

EJB Server
15
2 Tier Architecture.. Details
EJB Server
EJB Request
Response
Client
High Speed JDBC Driver
Database Server
16
ASE-EJB Architecture Components

• Database Server
• Responsible for spawning the EJB Server
• Responsible for responding to isql and ct-lib
  requests
• Listens on the TDS port
• EJB Server
• Responsible for responding to EJB requests
• Listens on the IIOP port
• Responsible for executing component methods

17
ASE-EJB Architecture Components

• High Speed JDBC driver
• Facilitates high speed communication between ASE
  and the EJB Server
• This bi-directional communication between ASE and
  the EJB Server happens through ASEs shared
  memory to which the EJB Server is attached to.

18
ASE-EJB Interface

• Configuration Parameters
• New Configuration parameter enable enterprise
  java beans to enable/disable EJB support in ASE
  with a valid ASE java feature license
• This is a dynamic option

19
ASE-EJB Interface

• Sybase Central plug-in for ASE
• Used to Configure a new EJB Server
• Used to specify the logical name, physical name
  and the port number where the EJB Server would
  listen
• Used to deploy components
• Used to Manage packages, components, listeners,
  connection caches etc
• Look and feel similar to Jaguar Manager

20
ASE-EJB Interface

• SQL Interface and Stored Procedures
• sp_extengine Used to start, stop and query the
  status of the EJB Server
• Syntax is as follows
• sp_extengine _at_logical_servername, _at_class,
  _at_command
• _at_logical_servername is the logical name of the
  EJB Server

21
ASE-EJB Interface

• SQL Interface and Stored Pr. (cont)
• Syntax (cont)
• _at_class is the class of servers, ASEJB is a new
  class
• _at_command is the command to be performed on the
  EJB Server and includes start, stop and
  status
• E.g..
• sp_extengine EJBServer, ASEJB, start

22
ASE-EJB Interface

• SQL Interface and Stored Pr. (cont)
• Shutdown automatically shuts down the EJB Server
  also
• An EJB Server cannot exist as a stand alone
  entity and has to have an ASE associated with it

23
ASE-EJB Interface

• Shared Memory Driver
• To use the High Speed Shared Memory driver the
  following System Property needs to be set
• SYBSOCKET_FACTORYcom.sybase.shmem.ShmemSocketFa
  ctory

24
Developing and Deploying EJB Components

• PowerJ
• The IDE of choice to develop and deploy
  Enterprise Java Bean applications in ASE
• Has the option of deploying the EJB either in the
  middle tier or in the database tier
• Helps in the generation of stubs and skeletons

25
Developing and Deploying EJB Components

• Sybase Central Plug-in for ASE
• Helps in the generation of stubs and skeleton
  code and also in the deployment of the components
  in the EJB Server

26
High Availability

• High availability support for session beans is
  automatic for an ASE/EJB Server pair
• If EJB Server A and EJB Server B were made part
  of a cluster, then when EJB Server A fails while
  executing a session bean, the client EJB request
  would automatically be serviced by EJB Server B
• For a stateful session bean, the state of the
  bean is stored in the database

27
High Availability

• For entity bean support, the database being used
  as a storage for the entity bean, needs to be
  configured as a proxy database in the companion
  server

28
High Availability
EJB Request
Primary db
Response
Primary ASE
Client
Proxy db
Companion ASE
29
High Availability
EJB Request
Primary db
Response
Primary ASE
Client
Proxy db
Companion ASE
30
High Availability
Primary db
Primary ASE
EJB Request
Proxy db
Response
Client
Companion ASE
31
Unified Login and Role Mapping

• A Single Login and Password interface is provided
  to login to both ASE and the EJB Server
• Role Mapping is done in order to ensure users
  with the right privileges have the authority to
  perform the appropriate actions
• The roles are maintained in ASE

32
Conclusions

• Significant performance benefits when Enterprise
  Java Beans with a lot of database operations are
  deployed in ASE
• Secure communication between ASE and the EJB
  Server happens through shared memory
• A Seamless interface can be used to develop,
  deploy and manage EJB Components

33
References

• Suns EJB Specification
• Enterprise Java Beans by Richard Monson-Haefel

34
Questions
35
Session No. DM203Enterprise Java Beans in
Adaptive Sever Enterprise
Girish Vaitheeswaran Senior Software
Engineer Database Server Technologies girish_at_sybas
e.com