Oracle ADF Architecture TV - Design - Service Integration Architectures

Real World ADF Design & Architecture Principles
Service Integration Architecture
ORACLE
PRODUCT
LOGO
15th Feb 2013 v1.0

Learning Objectives
•  At the end of this module you should be able to:
–  Understand the difference between SOAP services
and REST services
–  Understand which releases of Oracle JDeveloper support SOAP
and REST services with ADF and how to use them
–  Define a service integration strategy for Oracle ADF application
development projects
Image: imagerymajestic/ FreeDigitalPhotos.net

Program Agenda
•  Services Overview
•  ADF Service Integration Strategies
–  JAX-WS Integration in Oracle ADF
• Service Integration through ADF BC
• JAX-WS Proxy Client / POJO DC
• Recommended Practices
–  JAX-RS Integration in Oracle ADF
• Service Integration through URL DC
• Service integration through POJO DC / ADF BC

5 Copyright © 2012, Oracle and/or its affiliates. All rights reserved.5 Copyright © 2012, Oracle and/or its affiliates. All rights reserved.
Exercise
As an ADF developer, why
bother?

Why Bother
•  Enforce consistent business logic execution for multi channel
access
–  Web, SOA, Mobile
•  Shield data sources
–  Protect them from direct developer access
•  Application partitioning
–  Ease of maintenance
–  Sharing of business logic
Exposing Web Service APIs for Business Models

Web services are common in
web application development
and no longer SOA only.
Image: Ambro / FreeDigitalPhotos.net

SOAP Services
•  JAX-WS
–  Java API for XML-Web Services
–  Since Java 5, replacing JAX-RPC
–  Support for WS annotations
–  Support for asynchronous WS calls
JAX-WS

REST
•  Representational State Transfer
–  Exchanges the representation of a current data object state over the web
•  Design principle for stateless data transfers on the web based on unique
resource addressing using HTTP
–  Avoids the overhead of SOAP services
–  Addresses resources as nouns
•  Supports different data representations
–  Negotiated between client and server
–  Representation "encodes" the state of a resource at a specific point in time
–  A resource can have many different representations
•  Image, Text , XML, JSON, etc.

About JAX-RS
•  Java XML API for Restful Services
•  Java EE standard
•  Jersey is reference implementation
–  Bundled with Oracle JDeveloper 12c (+)
–  JAX-RS provides annotations for
•  Resource request path definitions
•  HTTP method mapping to service methods
•  Request URL parameter mapping to input parameters
•  Accepted data format
•  Response data format
•  etc.

SOAP Services vs. Rest Services
•  Self describing and discoverable
•  Machine understandable
–  Supports intermediary machine access as required in SOA
•  Require data transformation to be performed by the client
–  XML to JAVA using JAXB
SOAP

SOAP Services vs. Rest Services
•  Support for different response formats
•  Clients negotiate representation format by sending HTTP accept
header with list of media types they are happy to process
–  REST services decides which format to support
•  Support for human and machine interaction
•  Used by many popular Ajax frameworks
–  SOAP is hard to use with JavaScript
•  Preferred use with mobile clients
–  Less overhead
–  Security easier to implement
REST

Program Agenda

SOAP Service Integration in Oracle ADF
Web Service
Data Control
accesses
JAX-WS
Proxy Client
Web Service
Implementation
WSDL
accesses
JavaBean
Wrapper
ADF Business
Components
JavaBean
Data Control
instantiate

SOAP Service Integration in Oracle ADF
Caching Strategies for Best Performance
Web Service
Data Control
accesses
Cache
JAX-WS
Proxy Client
Web Service
Implementation
WSDL
accesses
JavaBean
Wrapper
ADF Business
Components
JavaBean
Data Control
instantiate

Program Agenda

Service Integration Through ADF BC
•  Who
–  Developers using ADF BC as their business service
•  Why
–  Seamless integration
–  Consistent business service API
–  Leverage ADF BC advanced functionality
•  How
–  Programmatic View Object
–  Programmatic Entity (for CRUD operations)
Who, Why, How

ADF Business Components
Programmatic View Object and Entity
JavaBean
Wrapper
JAX-WS
Proxy Client
Entity Object
CustomWsEntity
View Object
CustomWsViewObject
Application
Module
referenced by
exposed in
Custom WS View Object
Database View Object 2
Database View Object 1
ViewLink

Custom View Object and Entity
•  Entity
–  doDML
–  doSelect
•  View Object
–  create
–  executeQueryForCollection
–  createRowFromResultSet
–  getQueryHitCount
–  hasNextForCollection
Framework Methods to Override
Entity Object
CustomWsEntity
View Object
CustomWsViewObject
Application
Module
referenced by
exposed in

WS Based Programmatic View Object
•  Implementing parent-child relationship between programmatic views
–  Create ViewLink between parent and child view
–  Map parent PK VO attribute to child FK VO attribute
–  ViewLink defines BIND_<ATTRIBUTE NAME> bind variable
–  Bind variable is passed as Object[] params argument to
executeQueryForCollection method
•  Override method in custom VO IMPL class
–  "params" is an Array of Array[2]
•  [0] name
•  [1] value
–  Read bind variable and use in programmatic view object data query
Implementing Parent – Child Relationships

Program Agenda

JAX-WS Proxy Client / POJO DC
•  Who
–  Developers who don't use ADF Business Components
•  Why (compared to WS Data Control)
–  Flexible and powerful
–  Can be used to implement caching strategies
–  Pre- and post-processing of data
–  Pagination support
•  How
–  Create POJO Data Control from JavaBean wrapper
–  Optional: Implement ADF lifecycle methods
Who, Why, How

JAX-WS Proxy Client / POJO DC
JavaBean
Wrapper
JAX-WS
Proxy Client
POJO
Data Control

Program Agenda
•  Web Services 101

Service Integration
•  Use Web Service Data Control only for simple
service like weather reports or stock quotes
•  Use JAX-WS proxy client for all more complex
services and access them from
–  Programmatic view object and entity if your business service is
ADF Business Components as this allows for better integration
with database queried views
• Use View Objects only for read only access
• Use View Objects and Entities for CRUD Web Service integration
JAX-WS service

Service Integration
•  Use JAX-WS proxy client for all more complex
services and access them from
–  POJO Data Control
• If your business service is not ADF BC.
• If your business service doesn't require integration into an ADF
business component model
• If the WS access should be used in a bounded task flow deployed in
an ADF library for maximum reuse
JAX-WS service

Service Integration
•  Let the business case rule!
–  ADF BC is not a simplification framework for
WS access
•  Integrate WS when and where it makes sense
•  WS and ADF BC have different query and transaction behavior
–  If all your data sources are JAX-WS services, evaluate a POJO data
control approach
–  Implement strategy to ensure data queried from WS sources are locally
cached for better parent-child performance
JAX-WS service

Program Agenda

REST Service Integration in Oracle ADF
REST (Jersey)
Client
URL
Data Control
ADF Business
Components
JavaBean
Data Control
REST Service
Implementation
accesses
accesses

Program Agenda
•  Web Services 101

REST URL / REST DC
•  Who
–  Developers looking for simple integration of RESTful resources in Oracle ADF
applications
•  Why
–  REST is a popular service format many public sites use as a programmer API
–  REST is easy to use and comes with no overhead compared to SOAP
•  How
–  Configure URL DC with resources URI and http methods to invoke remote
resources
Who, Why, How

REST URL / REST DC
URL
Data Control access
REST service
ADF Connection
Architecture
Noun
@Path("<name>")
@GET
handleQueryRequest()
@POST
handleCreateRequest()
@ ...
...
read URI

Program Agenda

REST Jersey Client / POJO DC, ADF BC
•  Who
–  Developers who want to interact with REST response
•  Why
–  Pre- and post-processing of data
•  How
–  Create Jersey client from Web Application Description Language (WADL) file
–  Access Jersey client from POJO avoid impact when regenerating client class
Who, Why, How

REST Jersey Client / POJO DC, ADF BC
Jersey Client
REST
Proxy Client
REST service
accesses
JavaBean
Wrapper
ADF Business
Components
JavaBean
Data Control
extend or
instantiate
Noun
@Path("<name>")
@GET
handleQueryRequest()
@POST
handleCreateRequest()
@ ...
...

Exercise
I need to build ADF based user interfaces
for SOA Services (ESB/OSB).
Shall I use ADF Business Components to
integrate the services or POJOs and the
JavaBean Data Control?

Exercise
What would be a good discriminator for
when to use ADF BC and when to use
POJO?

Conclusion
•  There are several options available in ADF to
integrate Web Services
•  When choosing between ADF Business Components
and POJO DC (with JAX-WS and JAR-RS clients),
consider
–  SOA Services are not developed for a specific client
–  Data loading from services should be optimized. In a
parent-child query you should ensure data to be loaded
when a specific parent record is selected
–  Application user interface developers require a consistent
programming API as a contract between the client logic
they build and the business service
•  Think "productivity"

Further Reading
•  Oracle Magazine "Service Please"
–  http://www.oracle.com/technetwork/issue-archive/2012/12-jul/o42adf-1653060.html
•  http://www.oracle.com/technetwork/developer-tools/jdev/documentation/index.html
–  Oracle JDeveloper and ADF Documentation Library
–  Fusion Developer Guide
•  Part V Completing your Application
–  Using Programmatic View Objects for Alternative Data Sources
•  ADF Insider Recording
–  http://download.oracle.com/otn_hosted_doc/jdeveloper/11gdemos/adf-
service-integ/adf-service-integ.html

Oracle ADF Architecture TV - Design - Service Integration Architectures

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