Oracle ADF Beginner Best Practices

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Copyright © 2013, Oracle and/or its affiliates. All rights reserved.

Oracle ADF Programming
Best Practices for Beginners
Frank Nimphius
Senior Principal Product Manager
Application Development Tools

Program Agenda
 Simplify Your Development Choice

 ADF Business Components
 ADF Task Flow
 ADF Binding
 ADF Faces
 JavaScript
 Break Out Of Isolation

3


Simplify Your Development
Choice

4


Simplify Your Technology Choice
Choose a Development Approach

Database Oriented

Java EE Oriented

SOA Oriented

• EJB / JPA

• Services

 ADF Binding

• ADF Binding

• ADF Binding

 ADF Task Flow

• ADF Task Flow

• ADF Task Flow

 ADF Faces

• ADF Faces

• ADF Faces

 Data Visualization

• Data Visualization


 RDBMS
 ADF BC

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Simplify Your Technology Choice
Common Technologies

Database Oriented

Java EE Oriented

SOA Oriented

• EJB / JPA

• Services

 ADF Binding

• ADF Binding

• ADF Binding

 ADF Task Flow

• ADF Task Flow

• ADF Task Flow

 ADF Faces

• ADF Faces

• ADF Faces

 Data Visualization



 RDBMS
 ADF BC

6


ADF Business Components

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Application
Module
Data Model

View
Object
XML
Definition
References

View Object
Base Class
XML
Definition
References

AM
Base Class

8


1

*

Entity
Object
XML
Definition
References

Entity Object
Base Class

Architecture Best Practices

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Use ADF Business Components Preferences

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EntityImpl

YourOrgEntityImpl

YourAppEntityImpl

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12



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ADF Architecture Square
http://bit.ly/adfarchsquare
 Development
– Oracle ADF Development

Essentials
– ADF Code Guidelines (v1.00)
– ADF Naming and Project Layout

Guidelines (v2.00)

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Implementation Best Practices

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General Considerations
Custom Framework Extension Classes

 Always create and use custom base-classes for at least
– ApplicationModuleImpl
– EntiyImpl

– ViewRowImpl
– ViewObjectImpl

 Note that creating custom super classes for <object>Def classes are

less common

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Entity & View Object
When to generate Java Impl files

 Generate Java Impl files when entity objects are accessed from Java

or Groovy
 Ensure code that accesses entity objects directly uses type safe APIs
instead of the generic framework APIs
 Do not generate Impl classes without a need
– Keep code base size reasonable.

– Impl classes for the *def classes are rarely needed

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View Criteria
Prefer One View Object with Many View Criteria

 Not necessary to create separate VO that only differ by their WHERE

clause
 Apply view criteria declaratively when defining view accessor and AM
data model instances
– Use bind variables with View Criteria
– Be aware that "Ignore Null Values" options is of bad performance

 Avoid direct user input in ADF BC queries to protect against SQL

injection attacks
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Performance Tuning And Optimization
Developers always strive for "better"
 Premature optimizations as the root of all evil
– Measure Performance, don't guess it.
– If performance measures as bad, look for optimizations

 Make the general assumption that ADF will probably get it right
– Consider the greater cost of do-it-yourself (DIY)

 Think AM Pools!
– Good rule of thumb: One AM instance serves 10 - 15 users comfortably
– Size for peak load based on this.

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Read. Understand. Tune.
 http://docs.oracle.com/middleware/1212/adf/

adf-monitortune.htm

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ADF Task Flow

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Bounded Task Flow
Flows, Sub-Flows, Regions
Bounded Task Flow
Input Parameter
Input Parameter
Input Parameter

Return Value
Return Value

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Managed
Beans

ADF Task Flow
Architecture Best Practices

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Task Flow Oriented Architecture (TOA)
 Think task flow from design time on
– Inventory existing task flows
– Identify patterns and standardize on them

 Ensure objectives and requirements reflect task flow benefits
– Reuse, loose-coupling

 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

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Use Task Flow as a "Common Language"

 Use task flow diagrammer as "common language"
– Use task flow templates as blue prints
– Use verbs and meaningful names in control flow case names

 editOrder, createOrder,

manageEmployee

 Use the display and description properties of the contained

activities to explain the non-obvious

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Task Flow Design
Task Flow Sizing Considerations
 Build Composite Task Flows
– 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

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ADF Task Flow
Implementation Best Practices

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Handling Input / Return Parameter Values

 Save task flow input / return parameter values

in managed beans in pageFlowScope
– Easy to document
– Type safe API
– EL accessible
– Easy to discover and manipulate

input parameter values
– NPE protection

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Managed Beans

 Java classes configured in faces-config.xml, adfc-config.xml

or <task-flow-name>.xml
 Managed by JSF or ADF Controller
– Java EE scopes
 request, session, application

– Additional ADF scopes
 backingBean, view, pageFlow

 Hold code for UI related logic and data

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Bounded Task Flow & Managed Beans
Best Practice
 Always use the smallest possible scope for managed beans
– Helps Framework to "clean up" memory footprints
– Think "state"
 Does the managed bean need to keep state?
 If so, how long?

 Don't reference managed beans in session or application scope
– Violates task flow isolation and reuse

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Data Control Scope
 Use shared data control scope as often as possible
– Less database connections

– Simplifies task flow inter-communication
– Automatic parent view collection to child task flow detail

collection synchronization

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Task Flow Exception Handler
 Define an exception handler activity in every bounded task flow

 Leverage Task Flow Templates
– Use as Blueprint or Reference
– Define exception handlers for

all bounded task flows

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What Could Happen
Task Flow Exception Propagation
Memory Stack

!

Task Flow 1 View1

EH

Task Flow 2
Call
Task Flow 2 View2

Current Task Flow

!

Task Flow 4

EH

Task Flow 3
Call

Task Flow 3
Task Flow 3 View3

Task Flow 2
Task Flow 4
Call

Current Task Flow
Task Flow 4 View4

Method
Call

BANG!

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Task Flow 1

What Could Happen
Memory Stack

!

Task Flow 1 View1

EH

Task Flow 2
Call
Task Flow 2 View2

!
EH

Task Flow 3
Call

Propagate
Exception

Task Flow 3 View3

Task Flow 4
Call

Task Flow 2

Current Task Flow
Task Flow 4 View4

Method
Call

BANG!

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Current Task Flow

Propagate
Exception

Task Flow 1

What Could Happen
Memory Stack

!

Task Flow 1 View1

EH

Task Flow 2
Call
Task Flow 2 View2

!
EH
Current Task Flow

Task Flow 2

Task Flow 1

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Visual Example
!

BANG!
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Best Practices at a Glance
Wildcard Navigation
 Avoid cluttering diagrams for common navigation rules
 Use wild card navigation for common functionality
– Cancel
– Commit

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ADF Binding

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Understanding ADF Bindings
How Oracle ADF binds into JSF
Business Service
Web Service

ADF Data Binding
Data
Control

POJO

Data
Binding

JSF Page
JUCtrl Generic
Binding

Expression Language

ADF BC
EJB

ADF Faces Component
Tag (<af:name../>)

FacesCtrl
Binding

Server Side JSF Component
JMX
TopLink

BAM

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Component
Component Model
UI Renderer

Programming Against the Binding Layer
 Expression Language
– Current binding layer can be accessed from #{bindings} or ${bindings}
 Use from JSF components
– Populate UI component value #{bindings.firstName.inputValue}
 Use from PageDef file
– E.g. access field binding value - ${bindings.firstName.inputValue}

 Java
– ADF binding layer is represented by Java objects at runtime
– BindingContext.getCurrent()is the generic entry point

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Use Public APIs Only

 ADF classes have an API package and an IMPL package
– Define logical framework abstractions
– Simplifies implementation of future product changes

 APIs in IMPL package are internal-only
– Not to be used outside of framework
– Internal packages have "internal" in the naming (It’s a clue!)

 If you are not sure …
– Use EL in Java: #{bindings.allDepartments.treeModel.makeCurrent}

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Understanding ADF Programming
Example: Accessing the Binding Layer

import oracle.adf.model.BindingContext;
import oracle.binding.BindingContainer;
…
BindingContext bctx = BindingContext.getCurrent();
BindingContainer bindings = null;
bindings = bctx.getCurrentBindingsEntry();

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Example: Accessing Attribute Binding

AttributeBinding attributeBinding = null;
attributeBinding =
(attributeBinding)bindings.get("AttributeName");
/* set / get value */
attributeBinding.setInputValue(value);
attributeBinding.getInputValue();

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Example: Method and Action Bindings
//get method or action binding
OperationBinding methodBinding =
(OperationBinding)bindings.get("methodOrActionName");
//optional: if method expects arguments
Map paramsMap = methodBinding.getParamsMap();
paramsMap.put("argumentName1",value);
Object result = methodBinding.execute();
//check for errors, e.g. exceptions
List errors = method.getErrors();
If(!errors.isEmpty()){ …}

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Accessing Business Service Methods
Best Practice
 Encapsulate all model manipulation code in custom AM and/or VO

methods & invoke them declaratively
– Makes your app easier to regression test

 Only code that belongs in a JSF managed bean is…
– Complex, dynamic UI component manipulation
– Complex conditional navigation

 Even if you require backing bean code, invoke custom AM or VO

methods using action binding
– Guarantees uniform error handling

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Always Work Through the Binding Layer
Best Practice – Accessing Business Service Methods
View Layer

Business Layer

Business Service

Application
Module

Managed
Bean

Data Model

PageDef
attribute
binding
Text

method
binding

AM Impl
public void invokePlSQL()

Button
AM Client Interface
public void invokePlSQL()

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ADF Model Error Handler

 The ADF model error handler deals with
– All ADF binding errors
– Business service errors that occur when accessing a service trough the

ADF binding layer
 Formats and displays error message
 Default error handler skips the top-level JboException because it

only is a bundled exception wrapper for other business exceptions

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Build A Custom ADF Model Error Handler
Best Practice
 Extend oracle.adf.model.binding.DCErrorHandlerImpl and configure your custom

error error handler in DataBindings.cpx
 Override the following methods as needed
– reportException
 Override this method to analyze exceptions for errors you want to handle
– getDisplayMessage
 Override to change or suppress (null value) the displayed message
– getDetailedDisplayMessage
 Override this method to provide HTML markup formatted detail information

– skipException(Exception ex)
 Called by the framework to check if an exception should be ignored

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Configuring A Custom Error Handler

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ADF Faces

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ADF Faces Rich Client Components
Based on Java Server Faces Standard
 Ajax & HTML5 enabled JSF

components
 Pluggable look and feel
 Accessibility & internationalization
 Touch gesture support
 Built-in advanced functionality:
– Partial Page Refresh (PPR),

Partial Submit
– Drag and drop framework
– Dialog and pop-up framework

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Backing Bean
 "Special use" of a managed bean
– Contain UI Component references
 <af:inputText label="…" binding="#{BackingBeanName.lastNameField}"/>
– Must be defined in request scope
 JSF components are not serializable (!)

 Best Practices
– Avoid backing beans and perform dynamic component lookup using
 FacesContext.getCurrentInstance().getViewRoot().findComponent(…)
 Relative search: component.findComponent()

 org.apache.myfaces.trinidad.util.ComponentUtils.findRelativeComponent(…, …)

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When Using Backing Beans …

 Use separate beans for separate views
– Avoids "pinning" of UI components and their state
– If views are exactly identical, consider reuse

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Avoid Expression Language Gotcha
Manage Bean Scope – Prefix or don't Prefix?
 EL accessing managed beans in Java EE scopes
– Request, session, application
– No scope prefix
– #{beanName}

 EL accessing managed beans in ADF scopes
– backingBean, view, pageFlow
– Require scope prefix
– #{scope.beanName}, #{backingBeanScope.beanName}

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Put use of HTML on a "By Exception" List
Avoid Mixing HTML and JSF components
 HTML and JavaServer Faces are different technologies
– Markup oriented vs. component oriented
– Compile – Render, vs. multi stop request lifecycle

 Facelets in JSF 2.x support mixing of HTML and JavaServer Faces

components
– Prior to Facelets and JSF 2.x, mixing HTML and JSF is a no-go
– Still with JSF 2.0 problems may occur because ADF Faces components come with

their own sizing behavior (geometry management)
 Recommendation: Build pages and views with ADF Faces components

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Avoid ui:include and jsp:include Tags
 ADF PageDef file is not aware of ui:include or jsp:include references

in a page or view
– Included fragments fail at runtime if they use ADF bound components
– You can copy ADF bindings used by the included content into the view's

PageDef file.
 Prevents reuse of the fragments

 Recommendation
– Use ui:include and jps:include for layouts only (if at all)
– Use ADF regions to add ADF bound content to a page at runtime

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Use inlineStyle and contentStyle By Exception
Learn to Love Skinning
 inlineStyle property allows developers to add CSS to a component

rendering
– CSS is applied to top-level DOM component
– CSS is directly added to the page output
– Best Practice: Use ADF Faces skinning and reduce the use of CSS to the

absolute minimum (e.g. conditional color coding)
 contentStyle property allows developers to add CSS to the value content

area of an ADF Faces component
– Styles component content area better than inlineStyle but has same issue as

mentioned above

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JavaScript

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ADF Faces Client JavaScript Architecture
DOM
Form

Client Side

Server Side
Servlet

Label1
Label2
Label3

JSF
Lifecycle
OK

Component Tree
UI Components

UI Components
Form

Document

Peer Objects

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Form

View Root

Renderer

ADF Faces Client JavaScript Architecture
Features
 JavaScript component API
 af:clientListener
– Listens to DOM and ADF Faces component events

 af:serverListener
– XMLHttp JavaScript call to server
– Queued as custom event on client
– Answered by managed bean

 ExtendedRenderKitService
– Trinidad class to invoke JavaScript from Java

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Using JavaScript in ADF Faces
Best Practice
 Use JavaScript by Exception
 Don't overuse JavaScript and first try and find a solution in ADF Faces
 Put JavaScript code in external *.js files
– Include using af:resource

 Code against ADF Faces component model, not the browser DOM
– Component oriented vs. markup oriented
– "document.getElementById" is a serious programming mistake

 Don't use JS classes in internal packages
– See JavaScript docs

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Break Out Of Isolation.

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Join A Community
 OTN forum
– Best Practice

 Articulate your question well
– Take the same time for asking a question that you want

forum members to spend on answering it
– Keep questions short but comprehensive

– Include your JDeveloper version
 Use Google prior to asking to save time
 Contribute

 EMG
– Architecture, integration, concepts and infrastructure topics
– https://groups.google.com/forum/#!forum/adf-methodology

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Schau Dich Schlau
Make yourself a smart cookie by watching ADF Architecture TV

http://bit.ly/adftvsub

64


Best Practices Summary
Dress For Success

Always
work
through the
binding
layer

65


Don't fight
the
framework

Think
Task Flow

Best Practices Summary
Dress For Even More Success

Join a
Community
&
Participate

66


Use Case
Matters

Schau Dich
Schlau!

Join the Oracle ADF Community
http://oracle.com/ADF

@jdeveloper

/jdeveloper

67

JDeveloper

ADF Insider
ADF Architecture


Learn More at Oracle OpenWorld
Related sessions and labs

Title

Time

Location

Oracle ADF and Oracle ADF Mobile: Lessons Learned
in Real-World Implementations

Wed
11:45

Marriot – Golden Gate C3

Hands-on Lab: Developing Mobile Applications with
Oracle ADF Mobile

Wed
10:15

Marriot – Salon 12

One Size Doesn’t Fit All: Oracle ADF Architecture
Fundamentals

Thu
11:00

Marriot – Golden Gate A

Oracle ADF booth at the Oracle Demo Ground – Moscone South
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Oracle ADF Beginner Best Practices

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