Framework Logical Structure

Logical Structure:

  

·         Presentation layer

o    Java Servlets handle inbound HTTP requests from browser

o    Invoke data service objects when required

o    Various static data – e.g. control tables, language-specific messages and labels – are cached

o    Uses XSL/T technology to create HTML

·         Business layer

o    Data service objects are invoked from presentation

o    These services ultimately perform business functions

o    Service objects themselves are Java, but business logic could be implemented in Java or COBOL

o    Invoke data access objects to communicate with database

·         Data access layer

o    Uses Hibernate Object Relational Model (ORM) framework for database access and persistence

o    Java Database Connectivity API (JDBC) is used for SQL statements from COBOL

o    All database calls are routed through framework’s data access layer – application programs do not issue direct calls to database

Services:

·         ORACLE system makes heavy use of “services”

·         These are data access and update services

·         Implemented in Java at high level – Java or COBOL at lower levels

·         Access Oracle / DB2 / SQL Server

·         Each service has XML metainfo document describing its structure

·         Framework automates mapping of string-based browser data to service data structure using metainfo XML (more about this in XAI class)

·         Service Dispatcher routes Web servlet requests to Java or COBOL service …

·         Service dispatcher acts as conduit to business objects from presentation layer

·         A service invocation represents a database transaction

·         Invokes Java or COBOL service

·         Service dispatcher is invoked from Web servlet

·         Invokes appropriate service for Web request:

o    Page

o    List

o   Search

Page Service

·         “Top level” application service

·         Orchestrates display and update of all data for a root object and all its child objects – e.g. Person, Person Name, Person Phone, Person Id, etc.

·         Data is displayed on a single tab menu – across one or more child tab pages

·         Page service names end with “P” – e.g. Person service is CILCPERP.

• To apply Custom validations on page service we have to use Maintenance Extension. About Maintenance extension I’ll post in blog soon....

List Service:

·         Defines list of objects

·         Could contain nested lists

·         Used for list-oriented data – e.g. Customer Contacts

·         List service names end in “L” – e.g. CILCPCCL for Customer Contact list

·         Do not support database updates

Search Service:

·         Used to support ad-hoc user searches

·         Results similar to list services

·         Input is set of criteria and search mode

·         Search service names end in “S” – e.g. CILCPERS for Person search

We can also able to overwrite existing Search Service using OUAF technical component using java.