oracle adf architecture tv - design - advanced adf task flow concepts


Real World ADF Design & Architecture Principles Advanced ADF Task Flow Concepts

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LOGO

15th Feb 2013 v1.0


Learning Objectives

•  At the end of this module you should be able to:

– Understand the difference between copied and inherited task flow templates, their limitations and use cases

– Understand loose coupling and when it is okay to create dependencies between task flows

– Know about task flow design considerations in terms of granularity and size of individual task flows

– Use bounded task flows as a common language between developers as well as developers and domain experts

Image: imagerymajestic/ FreeDigitalPhotos.net


Program Agenda

•  Task Flow Templates •  Good Task Flow Design Practices •  Highly Reusable Task Flows


Task Flow Templates

•  Communication –  Use templates to discuss business processes with non-technical domain

experts

•  Reuse –  Use to implement pattern for reoccuring processes

• CRUD • Lookup

–  Use to enforce development standards and good practices

Reuse and Communication


Task Flow Templates

•  Define common functionality to be inherited by or copied into flows subsequently created bounded task flows

•  Use cases –  Property Settings –  Managed bean definitions –  Exception handling flows –  Logging –  Auditing –  Transaction behavior

•  Templates are either copied into new bounded task flow or referenced

Overview


Task Flow Templates

•  Template is a "blue print" for a family of related processes –  Bounded task flows built from a template usually need to modify the flow –  Later changes to the template should not be visible in bounded task flow

•  Beware! –  Ensure unique ID in the bounded task flow metadata when copying from

a template to not break MDS functionality

When to Copy from Templates


Task Flow Templates

•  Template contains common functionality –  Exception handling –  Managed beans –  Task flow entry / exit logging

•  Changes to the template should be immediately reflected in bounded task flows

•  Be aware! –  Before JDeveloper 12c: Activities in the referenced template don't show in visual

editor when designing bounded task flows –  Properties inherited from a referenced template cannot be changed for a task flow

When to Reference Templates


Example: Jobs Task Flow


Tf-fragment-template


Task Flow Templates

•  Avoid name collisions with consuming task flows •  Collisions will override functionality •  Standardize on template naming schemes for:

–  Activities –  Parameter –  Managed beans

Avoid Pitfalls


Program Agenda


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How granular should our task flows be?

Exercise



Task Flow Design

•  Small task flows: –  Require a lot of calling and maintenance management overhead –  Reasonable sizes for distributed team development –  Provide ultimate flexibility in architecture

•  Large task flows: –  Require less calls and maintenance management overhead –  Less flexible as you can't call discrete functionality within the flow –  Memory footprint likely bigger than small task flows

Task Flow Sizing Considerations


Task Flow Design

•  Meet in the Middle –  Larger task flows built out of several smaller task flows –  Only top level task flow exposed for reuse –  Encapsulates task flow dependencies

• Good for distributing work among developers • Dependency management "by agreement" in smaller teams • Smaller memory foot print through load-on-demand and task flow

private memory scopes

Task Flow Sizing Considerations


Task Flow Design

•  Think "unit-of-work" and factor task flow functionality into subflows –  Share Data Control frame with sub-flows –  Hide sub-flows from showing in ADF library –  If you cannot fully explain and describe a task flow in 60 seconds it

probably is too big

•  If you save a lot of data in pageFlowScope, keep the task flow small and exit at earliest opportunity

•  Keep task flows that run in their own transaction as small as possible and exit them at earliest opportunity

Sizing Guidelines

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How much should I care for loose coupling?

Exercise



Loose Coupling Where Would You Care The Most?

Bounded Task Flow

Task Flow Call Activity

Bounded Task Flow


Bounded Task Flow


Bounded Task Flow


Bounded Task Flow


Bounded Task Flow


ADF Library

Library internal

Library internal

Library internal

Library internal


Program Agenda



Maximize Reuse

•  Define and configure: –  A set of input parameters that allows you to configure various use cases –  A router activity as the default activity to enable conditional flows –  Dynamic iterator bindings to use a task flow both as a master region or

detail region –  Configure display properties of UI components based on task flow input

parameters


Example 1: Dynamic Task Flow Entry


Example 2: Dynamic Iterator Binding

•  Solution –  Dynamically reference view object instance name from iterator binding

property –  Dynamically generate new View Object instance in ADF Business

Components model •  Use method call activity to invoke View Object instance creation before rendering view •  Use View Criteria to shape query result displayed by View Object

•  What does this help with? –  Allows multiple regions to be added based on the same task flow with

shared data controls configuration –  Each region shows different row data

Use case: Multiple Instances of Task Flow with Shared DC


Multiple Instances of Task Flow with Shared DC

Task Flow

af:region Parent View

Managed Bean Page Flow Scope

View <file>.jsff

<file>PageDef.xml

allEmployeesIterator

allEmployees View Object

Instance Name

Input Parameter

reads from

has "Binds" property set to

Input Parameter

Query argument (e.g. 60 for querying

department 60)


Multiple Instances of Task Flow with Shared DC ADF BC Implementation (AM Impl) public void createUniqueEmployeesVOInstance(Integer departmentId, String instanceName) {

ViewObject existingVO = findViewObject(instanceName); if (existingVO == null) { //create a new view object based on the existing Employees View Object ViewObject newVO = this.createViewObject(instanceName, this.getallEmployees().getDefFullName()); ViewCriteria vc = newVO.createViewCriteria(); ViewCriteriaRow vcRow = vc.createViewCriteriaRow(); //ensure View Object instance returns data specified by the //task flow input parameters vcRow.setAttribute("DepartmentId", "= "+departmentId); vc.addElement(vcRow); newVO.applyViewCriteria(vc); } else { //instance will be reused } }


Conclusion

•  Task Flow templates are blueprints that provide a visual and common language between IT professionals and business domain experts

•  Document task flows using diagram annotations •  Keep task flows "just big enough" but as small as

possible so that task flows that open a separate transaction or task flows that keep large objects in memory are exited early.


Task Flows at the Heart of Oracle ADF

There is nothing more important than understanding task flow-oriented design and architecture when developing Oracle ADF applications


Further Reading

•  ADF Insider –  Task Flow Overview Part 1

•  http://download.oracle.com/otn_hosted_doc/jdeveloper/11gdemos/taskflow-overview-p1/taskflow-overview-p1.html

–  Task Flow Overview Part 2 •  http://download.oracle.com/otn_hosted_doc/jdeveloper/11gdemos/taskflow-overview-p2/taskflow-overview-p2.html

oracle adf architecture tv - design - advanced adf task flow concepts

Technology

bounded task flows

task flow

task flows

exercise image

rights reserved

common language

multiple instances

loose coupling