Oracle ADF Architecture TV - Design - Task Flow Overview

Real World ADF Design & Architecture Principles
ADF Task Flow Overview
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 page oriented and
task flow oriented development
–  Explain the benefits ADF task flows provide
–  Understand bounded task flow metadata files and properties
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Program Agenda
•  Characteristics and Benefits of Task Flows
•  Service Oriented Development
•  Task Flow Design Fundamentals

ADF Task Flow - Key Benefits
•  Partitions and modularizes large business applications
•  Visual task flow diagrams
–  Provide a shared language between developers and domain experts
•  Reusable application flows published via ADF Libraries
•  Can have isolated transactions
•  Can be used as "remote services with a UI"
•  Supports traditional web navigation model and rich internet
navigation models
•  Support for nested control flows

ADF Task Flow - Key Benefits
•  On-board security
–  ADF Security
–  Bounded task flow browser access protection
•  Additional memory scopes
–  Avoid memory attribute name conflicts
–  Avoid memory bloating
•  Improved and declarative exception handling
•  Load on demand
•  Static and dynamic configuration

Secret of Oracle ADF Rockstar Programmers
"Develop User Interface Services – Not Pages"
Steven Davelaar, "Building Highly Reusable Task Flows"
http://www.slideshare.net/stevendavelaar/reusable-taskflows

Program Agenda

Analogy
Service Orientation
“When building distributed solution logic, design
approaches revolve around a software engineering theory
known as the separation of concerns. In a nutshell, this
theory states that a larger problem is more effectively
solved when decomposed into a set of smaller problems
or concerns."
Thomas Erl, "SOA: Principles of Service Design"

Service Oriented Development
•  SOA uses the concept of services
–  Predominately about services and information flow
–  Fine grained services are consumed by larger composite
–  Web based analogy to SOA
–  Suits ADF development
–  About web tasks/processes and how they’re chained
–  Fine grained task flows are consumed by larger apps
–  Aligns with the UX concepts of task driven design

11 Copyright © 2012, Oracle and/or its affiliates. All rights reserved.11 Copyright © 2012, Oracle and/or its affiliates. All rights reserved.
Hands up, are task flows
services?
Exercise
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Task Flow Oriented Architecture (TOA)
•  Think task flow from design time on
–  Create a task flow portfolio plan
• Inventory of existing task flows
• Requirement for new task flows
•  Ensure objectives and requirements reflect task flow benefits
–  Reuse, loose-coupling
•  Use parent task flows to orchestrate child flows
•  Identify patterns and standardize on them

13 Copyright © 2012, Oracle and/or its affiliates. All rights reserved.13 Copyright © 2012, Oracle and/or its affiliates. All rights reserved. Image: imagerymajestic/ FreeDigitalPhotos.net
•  Knowing about SOA and service principles is a valuable
starting point for developing Task Flow best practices
•  Task Flows prepare applications for change
•  Task Flows implement business use cases or parts of
•  Task Flows separate process flows from business logic
•  There is no fixed sizing recommendation: Sky is the limit
and common sense a good judge

Program Agenda

Java Server Faces and MVC
Responsibility of the Controller
request
response View Model
Controller
Faces Servlet
faces-config.xml
component
events
Component Model
Converter, Validator,
Renderer
JSF document
Business Objects
(Managed Beans)
Phase Events
Component event
Listener and action
handlers

ADF with ADF Controller and MVC
Responsibility of the Controller
request
response View Model
Controller
Faces Servlet
adfc-config.xml
component
events
ADF Binding
Converter, Validator,
Renderer
JSF document
Data Control
(Business Service)
Phase Events
Component event
Listener and action
handlers

Bounded Task Flow
•  XML defined in View Controller
project
•  Located in WEB-INF directory or
(better) sub-folder(s) therein
•  XML
–  Defines task flow behavior like transaction
management and Data Control sharing
–  Defines activities
•  Activities reference views, methods, operations,
task flows, switcher statements
–  Defines managed beans used in task flow
–  May reference task flow template

Bounded Task Flow Diagram

Bounded Task Flow Properties

Properties
Property Description
Default Activity Activity that is invoked first when a bounded task flow is called.
Exception Handler Activity that is called by the framework in case of an exception
Initializer Invokes managed bean method upon task flow initialization before any activity
is executed.
Finalizer Invokes managed bean method upon task flow exit using return activity.
URL Invoke Bounded task flows using JSPX documents may be called directly from a
browser URL. This property defines which task flow is browser accessible and
which task flow can only be accessed from within an ADF application.
Managed Beans Managed bean definitions for use within the bounded task flow.
Input Parameter Definitions API contract between the bounded task flow and the calling task flow or view.
Commonly Used in Bounded Task Flows

Properties
Property Description
Return Value Definitions API contract between bounded task flow calling task flow. Requires task flows
called via task flow call activity
Train Defines whether or not the bounded task flow exposes a train model for
navigation
Critical If save point feature is used, critical ensures a save point is taken when the
task flow is left for the application to recover to this state
Transaction Defines the transaction setting for the bounded task flow and whether the data
control is shared or not (isolated).
Also defines if an implicit save point is taken when navigating into a bounded
task flow that does not run in its own transaction
Commonly Used in Bounded Task Flows

Task Flow Communication
•  Input Parameter
•  Return values

Exception Handling
•  Exceptions can be mapped to an activity
•  Called when exceptions are thrown
–  Not a “normal” part of a flow
<exception-handler>unexpectedErrorPage</exception-handler>

About ADF Regions
•  Display task flows in independent areas of a page or a page
fragment
•  Executes a task flow without requiring the parent view to refresh
•  Key enabler of enterprise Web 2.0 development with the Oracle
Fusion development platform
•  Allows building desktop like web user interfaces that unveil the real
power of Ajax
•  Basis of UI Shell layout pattern

Use it Inside Another View

How-to create an ADF Region
•  Drag bounded task flow to visual page editor
–  Task flow must use page fragments

Conclusion
•  Think task flow oriented architecture when
building ADF applications
•  Bounded task flow and region is the most
common pattern used when designing ADF
applications
•  Bounded task flows can be deployed and reused
as ADF libraries

Further Reading
•  http://www.oracle.com/technetwork/developer-tools/jdev/
documentation/index.html
–  Oracle JDeveloper and ADF Documentation Library
–  Fusion Developer Guide
•  Part III Creating ADF Task Flows
–  Getting Started with ADF Task Flows
–  Working with Task Flow Activities
–  Using Parameters in Task Flows
–  http://www.oracle.com/technetwork/developer-tools/jdev/adf-task-flow-
design-132904.pdf

Oracle ADF Architecture TV - Design - Task Flow Overview

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