Thursday, May 3, 2012

OJMCEA Notes

OOP:
Inheritance: inherit properties and method from object
Abstraction: Essential character distinguish from other object
Encapsulation: Seperation (hiding) external aspect
Polymorphism: assign different behaviour to something that was declared in a parent class

2 tier architecture model:
Cons:
1. validation intensive
2. each client need to make connection directly
3. not very maintainable
4. only horizontal scalability ?

webservice features:
Static and dynamic client call
Synchronous and Asynchronous WS call


SOAP Authentication:
WS Header
SOAP Message:
1. Require Envelope
2. Optional Header
3. Require Body
4.  Optional Fauilt

JAX-WS: client doesn't need WSDL and XML document



Strategy design pattern:
subclassing alternative
eleminate conditional statement
extend model without change code

Template method:
Skeleton of an algorithm

Proxy:
placeholder for other object to control/access it

Decorator:
pre and post processing .

Service Activator:
Invocation of business service / EJB without  waiting for the result
Integration of publish/subscribe and point to point messaging
Perform business task that locigally composed of several business task


MTOM: Sending binary from/to webservices

Signed jar: 
Doesn't mean that the sender is authentic,

Web.xml deployment descriptor:
1. protected url
2. authentication mechanism


JSF Phase:
Request:
Restore View
Apply Request
Validation
 Response:
Update Model
Invoke
Render


Servlet destroy for:
Keep track how many thread running
Clean shutdown by having destroy method, notify long running thread & wait to complete
Long running method poll periodically, check shutdown, or if stop working, clean and return

 N-TIERS:
Client Tier
Web Tier
EJB Tier / Business Tier
EIS Integration Tier
EIS TIer

JMS:
Note: JMS doesn't define functionality that addresses load balancing, fault tolerance, security, and administration. Such mechanisms must be provided by JMS providers.

 MDB:
MDB not accessed via interface
Instance variable of MDB can keep state accross handling of client message


BASIC OOP:
Encapsulation
Inheritance
Polymorphism

Delegation
Delegation is the simple yet powerful concept of handing a task over to another part of the program. In object-oriented programming it is used to describe the situation where one object defers a task to another object, known as the delegate