Worst Practices for Developing an ADF

ApplicationUKOUG ADF EMG Version 12.1.2.3.4.0.0b

Build WORST_PRACTICES_12.1.2.3.4.0.0b_UKOUG_2013 ADF EMG

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Paco van der LindenAMISwww.adfplus.com@pavadeli

Wilfred van der DeijlThe Future Groupwww.redheap.com@wilfreddeijl

About us

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Steven DavelaarOracleateam-oracle.com@stevendavelaar

Wilfred van der DeijlThe Future Groupwww.redheap.com@wilfreddeijl

About us

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Ideal project

● 1 developer

That’s you of course!

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Threats to a healthy ADF project

● Customer / Business / Functional designer

● Architect

● Project manager

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Threats to a healthy ADF project

● Customer / Business / Functional designer

● Architect

● Project manager

● Other developers

● Graphic designer

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Other Developers…Are not a member of ADF EMG

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Other Developers…Do not use ADF EMG Taskflow Tester

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ADF EMG Taskflow Tester - Wiki

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ADF EMG Taskflow Tester

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Other Developers… Don’t add ADF Source code library

● How to get ADF Source○ Go to support.oracle.com○ Log Service Request for JDeveloper/ADF○ “ADF Source Code Request” as problem type○ Sign agreement and upload to SR○ Get access to ZIP, typically within one day○ New versions don’t need new agreement

● Allows debugging of ADF framework

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Other Developers… Don’t add ADF Source code library

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Other Developers… Don’t adhere to ADF Code Guidelines

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ADF Code Guidelines

● 38 pages of excellent content by ADF guru’s● Topics include:

○ General Code Guidelines○ ADF Business Components○ ADF Faces○ ADF TaskFlows○ ADF Binding Layer○ Security○ High Availability○ … and more

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Other developers

● Don’t adhere to your project specific coding guidelines

● Other developers need your help○ Reserve time to review each other’s version control

commits○ You might learn from their code as well!!

● Reserve time to perform QA checks○ Against ADF coding guidelines and project specific

guidelines○ ...or automate this

■ come back tomorrow 10:15 - Exchange 6“Quality Assurance with JDev Auditing Framework”

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Threats to a healthy ADF project

● Customer / Business / Functional designer

● Architect

● Project manager

● Other developers

● Graphic designer

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Graphic designer - Pitfalls

● Website ≠ Application

● “HTML is for semantics, CSS is for layout…”○ ADF Fragment ≠ HTML, ADF skin ≠ CSS○ ADF Skin → primarily colours,

ADF Fragment → the rest

● Bad practice: CSS for layout management

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ADF Skinning Tips

● Use stand-alone Skin Editor

● Use ADF component selectors○ don’t look at the generated HTML○ use ADF Faces Skin Selectors Tag Reference

● Choice○ UI Designer to learn ADF skinning (preferred choice)○ ADF developer to learn CSS

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How to Write Code

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Logging

● Bad practice: System.err.println()● Best practice: ADFLogger

○ Configure at Runtime without restart○ Analyze Log for Performance○ Time your own code○ Better insight into ADF Framework internals

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ADFLogger - Runtime Configuration

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ADFLogger - Runtime Configuration

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ADFLogger - Log Analyzer

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...or open log file from other (production) server

bit.ly/adflogger

Time custom code withADFLogger::begin andADFLogger::end

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Understanding ADF Layers

● Bad: code ADF applications like open source frameworks

● What do we mean by that?○ All application state is kept in ViewController:○ Lots of data queried from ADF BC and stored in JSF

managed beans or entries in JSF memory scope maps

○ State passed back to ADF BC on subsequent requests: AM methods with lots of arguments

● Good: leverage ADF BC Active Data Model○ Easy access to previously entered data○ Row Currency management

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Understanding ADF Layers

● Signs of ViewController doing ADF BC work○ import oracle.jbo…○ Iterating RowSets○ Storing lots of data in memory scopes or managed

beans. Should only contain true UI state○ Calling ApplicationModule methods with lots of

arguments even when using binding layer● Project Audits often show 50-80% of

ViewController code is unnecessary○ Either completely redundant○ ...or should be moved to ADF BC layer

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ADF Facesa.k.a. the ViewController project

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ADF Lifecycle - Immediate property

● Bad: I run into issues, let’s try immediate=true● Big difference: immediate on input component

vs input on command component● Almost always wrong in input components● Make sure you understand both JSF lifecycle

and ADF Optimized Lifecycle

● Steven Davelaar’s 18 Lessons○ also available as ADF Insider Video

bit.ly/jsf-lifecycle

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Know your ADF Memory Scopes

● Bad: Overuse of SessionScope & PageFlowScope

● Can have significant impact on mem usage● Good: The smaller, the better● Do not cache shorter living objects

○ Should be cheap to request each time when needed○ Can have disastrous consequences, for example

caching binding objects

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Extreme Disastrous Caching

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Extreme Disastrous Caching

Memory Scopes Guidelines

● SessionScope○ only use for user context○ often (UTF) PageFlowScope is better

■ Two browser tabs share SessionScope but have independent UTF PageFlowScope

● RequestScope○ often BackingBeanScope is better○ each ADF Region or Declarative Component has own

BackingBeanScope but share RequestScope● Bad: Accessing SessionScope beans from BTF

○ BTF should be reusable and not rely on SessionScope○ taskflow parameters are there for a reason○ Use ADF EMG TaskFlow Tester to ensure

independence

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“My ADF application is memory hungry”

We might have a (small) part of the solution

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JSF Component BindingJDeveloper Generated Code

<af:inputText binding=”#{pageFlowScope.MyBean.lastName}”/>

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JSF Component Binding

● First ask yourself if it is really needed● binding=”#{pageFlowScope.MyBean.lastName}”

references UIComponent in PageFlow bean● UIComponents should be released after each

request● But Managed Bean might require

PageFlowScope for its functionality

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JSF Component BindingComponentReference

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Enhancement Request logged

“My JSF Component seems to travel around”

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Building Component Tree

bit.ly/compbind

binding attribute

create component

call getter

call setter

create component

use component

No

Yes

Not Null

Null

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a.k.a. the Model project

ADF Business Components

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ADF BC Data Model - Master DetailBeware of excessive querying

Navigate row here...

Requery(if populated)

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ADF BC Data Model - Master DetailPrevent excessive querying

● Use top level ViewObject instances with bind variables

● or reset detail ViewObject on master row navigation

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bit.ly/masterdetail

ADF BC Data Model - Master DetailPrevent excessive querying

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“I encountered a dramatic ADF bug!!!Sometimes users lose entered data when the

application is under heavy load.”

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Disable Application Module Pooling

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Don’t Simply passivate all!

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“ADF has huge performance problems!!!When under heavy load requests can take

several minutes.”

“Besides, what is this PS_TXN table for? It is eating up our tablespace.”

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Don’t Simply Passivate All

● Every ViewRow with transient atts is persisted

● During activation all state is applied

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Simply passivate all?

○ Every ViewRow with transient atts is persisted

○ During activation all state is applied

No!

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What is passivated?

○ Set logger:oracle.jbo.server.Serializer

○ To:

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What is passivated?

○ Set logger:oracle.jbo.server.Serializer

○ To:

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“My ADF application is hacked!!!Sometimes users see data from other

sessions.”

“By the way, I did test the application with AM pooling off.”

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Application Module RecyclingNot Losing, but Leaking state

● AM Instances Recycled for other users under load

● Not detected by disabling AM pooling!

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Detecting State Leakage

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Default AM Pool Tuning

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Default ViewObject TuningW

Eclipse Memory Analyzer Tool

bit.ly/eclipsemat

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Eclipse Memory Analyzer Tool (MAT)

● Make heap dump of running serverJDK_HOME/bin/jmap -dump:file=path jvm_process_id

● Download and run standalone Eclipse MAT● Inspect all objects in heap● Query Heap Objects● Predefined Reports and Tools

bit.ly/eclipsemat

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Java Mission Control

bit.ly/miscontrol

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Java Mission Control

● Any version of JRockit● Hotspot (aka Sun JVM) since 1.7.0_40● Record a period of time● Analyze

○ CPU performance○ Memory Usage○ Garbage Collection○ Thread Concurrency○ etcetera

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Miscellaneous

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Password management

● Bad: Credentials in clear text (eg. web.xml)● Worse: Override with deployment plans

bit.ly/secure-adf

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Reading Credential Store

bit.ly/secure-adf

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Load/Stress Testing

● 5 developers on a Friday afternoon:“Ready…. Set…. Go”

● Every ADF project initially has performance issues

● Consider ○ JMeter - Free open source, not optimized for ADF○ Oracle Application Testing Suite - ADF aware

● Requires○ Production like testing environment○ Good knowledge of chosen test tool○ 10 days setup (assuming test tool experience)

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Further Reading● bit.ly/adflogger

○ ADFLogger Custom Timings● bit.ly/secure-adf

○ FMW Credential Store● bit.ly/eclipsemat

○ Memory Analyzer Tool● bit.ly/miscontrol

○ Java Mission Control● bit.ly/jsf-lifecycle

○ Steven Davelaar’s JSF Lifecycle Lessons● bit.ly/compbind

○ JSF Component Bindings● bit.ly/masterdetail

○ Lazy Master Detail Query

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That’s all folks!

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