oracle adf architecture tv - design - service integration architectures

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Real World ADF Design & Architecture Principles Service Integration Architecture

ORACLE PRODUCT

LOGO

15th Feb 2013 v1.0

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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

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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

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Exercise

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As an ADF developer, why bother?

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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

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Web services are common in web application development

and no longer SOA only.

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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

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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.

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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.

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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JAX-WS Proxy Client / POJO DC

JavaBean Wrapper

JAX-WS Proxy Client

POJO Data Control

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Program Agenda

•  Web Services 101 •  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

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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

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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

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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

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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

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REST Service Integration in Oracle ADF

REST (Jersey) Client

URL Data Control

ADF Business Components

JavaBean Data Control

REST Service Implementation

accesses

accesses

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Program Agenda

•  Web Services 101 •  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

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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

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REST URL / REST DC

URL Data Control access

REST service

ADF Connection Architecture

Noun @Path("<name>")

@GET handleQueryRequest() @POST handleCreateRequest() @ ... ...

read URI

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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

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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

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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() @ ... ...

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Exercise

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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?

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Exercise

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

POJO?

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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"

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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

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