Oracle ADF Architecture TV - Design - Task Flow Navigation Options


Real World ADF Design & Architecture Principles Task Flow Navigation Options

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15th Feb 2013 v1.0


Learning Objectives

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

– Understand the different ways task flows can be combined – Appreciate that the different way task flows call or embed each

other provide functionality and introduce limitations –  Identify issues of runtime performance and memory consumption

based on your task flow navigation patterns

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Program Agenda

•  Task Flow Navigation •  Unbounded vs Bounded Task Flows •  Types of Interfaces •  Inter-task flow navigation

– Stack navigation – Network navigation – Hybrid navigation – Dashboard navigation – Parallel navigation


Task Flow Navigation

•  Task flows provide different navigation patterns, both – Within the navigation you create at DT in UTFs and BTFs – Also due to the limitations/features of each – And also how task flows call each other

•  This can influence the user experiences •  And can have runtime performance considerations


Program Agenda



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Unbounded Task Flow Example


Unbounded Task Flows

•  There is no set start or end to the UTF – User can enter/exit application at any point

•  Navigation can be: – User free form

• Minimum amount of steps to get to any activity is 1 •  Isolated activities are still accessible via URLs

– Structured at design time • Developers optionally define static uni or bi-directional navigation rules • Wildcards provide a uni-direction navigation

Key Navigation Features


Bounded Task Flow Example


Bounded Task Flow Navigation

•  One defined entry point, multiple defined exit points •  No free-form navigation •  Uni & bi-directional & wildcard navigation available •  Activities are not accessible via URL •  The minimum number of steps to any activity is defined at design time •  Isolated nodes are inaccessible

Key Navigation Features


Program Agenda




Drill Up/Down Interface


Wizard Interface


Dashboard Interface


ADF UI Shell


Program Agenda

•  Task Flow Navigation •  Unbounded vs Bounded Task Flows •  Types of Interfaces •  Inter-Task Flow Navigation

– Stack Navigation – Network Navigation – Hybrid Navigation – Dashboard Navigation – Parallel Navigation


Inter-Task Flow Navigation

•  Definition: How task flows call task flows •  To call a BTF based on pages we use a task

flow call •  To use a fragment BTF we embed the BTF

as a region – Either in a page – Or another fragment – Contained within another task flow

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Stack Navigation •  Suitable for page or page fragment task

flows

•  One task flows calls another without terminating first – A source task flow calls a destination task

flow – Control is passed to the destination task

flow until it terminates – Upon which control is passed back to the

source/caller

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Stack Navigation – Runtime Behavior

•  Task flow calls/returns allow stack to grow/shrink

•  In the stack –  The state of the source task flow is

persisted over the call –  The state of the destination task flow

exists for its life

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Stack Navigation – Advantages/Disadvantages

•  As we progress into the stack –  The previous task flows are still active –  Their state is stored in memory –  Consuming more memory the deeper in the stack we go

•  Vice versa, on returning to previous item in the stack –  There’s no need to restore the state, requery data –  It’s stored in memory

•  The stack order is inflexible (tightly coupled)


What Could Be Stored in Memory? •  ADF BC AM/VO/EOs

•  For period of request (could be passivated but will live at least for the request)

•  ADF BC has no knowledge of what BTFs use what VOs/EOs, so it cannot selectively passivate/activate content

•  Plus user data map in session

•  Binding layer objects •  Bounded task flow state and pageFlow Scope

•  Task Flow state is kept in a HashMap in user session •  The deeper the stack, more memory consumed

•  UI component tree and managed beans


Stack Navigation


Network Navigation

•  Chains task flows using a composite task flow – Composite comprises task flow

calls and navigation rules between them

–  Individual task flows do not call each other

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Network Navigation – Runtime Behavior

•  At most there’s only 2 task flows on the stack –  The composite and the called

task flow

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Network Navigation – Advantages/Disadvantages

•  Smaller memory footprint •  If we need to revisit a previous task flow, as it’s state is lost, we

need to do additional processing to reestablish the state


Network Navigation


Hybrid Navigation


Dashboard Navigation

Task Flow

Page/Fragment

Region

Bounded Task Flow

Fragment Fragment

Bounded Task Flow

Region Fragment Fragment


ADF UI Shell



•  Page/page fragments includes one or more regions •  Regions are nested calls to other task flows

•  Nested navigation is independent of parent task flow •  Can be stack, network or hybrid

•  Task flow stack is always minimum of 2 deep



•  Nested BTFs can communicate to parent through contextual events and parent actions

•  On termination of nested BTF there’s no way to access the BTF’s return parameters

•  Each region is equivalent of 2 level stack •  State of caller runs in parallel with nested region

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The more regions you have: the more memory is required, more processing is required,

more page interactions; this makes the developer’s and

maintainer’s job harder


Parallel Navigation

•  BTFs can be embedded as: –  Inline popups = Nested region navigation – External browser windows or tabs = Parallel navigation

•  Same user HTTP session •  Different pageFlowScope, backingBeanScope beans and

processing •  Need to share and separate state carefully


Conclusion

•  The manner in which you call task flows can influence: –  The user experience –  Which features you have at your disposal –  What limitations you will need to workaround –  And impact the performance of your system


Further Reading

•  Fusion Developer's Guide for ADF v11.1.2.3.0 –  Section 19.6 Using Task Flow Call Activities

•  http://bit.ly/adfdevguide11123sect196 –  Section 19.0 Using Parent Action Activities

•  http://bit.ly/adfdevguide11123sect199 –  Section 38 Using Contextual Events

•  http://bit.ly/adfdevguide11123sect34

Oracle ADF Architecture TV - Design - Task Flow Navigation Options

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