This document provides an overview of transactions and data controls within the Oracle ADF framework, emphasizing their roles in managing state and isolating user transactions. It discusses different types of data controls, their challenges, and solutions, including shared and isolated data control scopes. The content aims to align traditional transaction concepts with ADF functionalities, while providing insights into task flow configurations and implications on memory and database connections.

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Task Flow Data Control Scope Options
ORACLE
PRODUCT
LOGO
Real World ADF Design & Architecture Principles
15th Feb 2013 v1.0

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Learning Objectives
• At the end of this module you should be able to:
– Understand how the traditional concept of transactions
aligns to that of ADF
– Identify different data controls and their transaction capabilities
– Explain the influence of the task flow data control scope option
and how it relates to data controls
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Program Agenda
• Transactions Revisited
• ADF Data Controls
• Task Flow “Data Control Scope"

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In terms of database systems what is a
transaction? Why are they needed?
In ADF where are the transactional
capabilities defined?
Exercise
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Transactions Revisited
• The common definition
– A collection of work with a start and end
– Commit or rollback acts on the entire collection of work
– If an errors occur we don’t get stuck half way
– Other users are isolated from the transactions
– Only future transactions see the results

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Transactions – What You Forgot
• Remember transactions aren’t just about commit and rollback
– They allow one user to chain operations together
– Not just separate atomic actions
– Each operation sees the previous changes within the transaction
– Not visible to other users, but are visible to the current user
– As such transactions are also a form of state management

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Where in ADF are the
transactional capabilities
exposed (defined) to the UI
layer again?
Exercise
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Transactions & Data Controls
• Data controls provide the transactional APIs in ADF
– Remember this isn’t just commit and rollback
– But also state management
• Typically one instance is given to each user session
– This separates users’ transactions
• Dependent on design
– A user can be given multiple instances to perform multiple
transactions

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Program Agenda
• Transactions Recap
• ADF Data Controls
• Task Flow “Data Control Scope"

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ADF Data Controls Types
• ADF BC
• EJB/JPA
• POJO
• RESTful/URL
• SOAP/Web service
• Custom data controls
All designed
to carry state
EJB/JPA out-of-the-box
uses an implicit commit
model
Only ADF BC supports
explicit commit &
rollbacks

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ADF Data Controls Challenges
• If transactions are logically mapped to navigating groups of web pages
– Q: How do we map the data control transaction to these boundaries?
• If we need to support separate transactions per session
– Q: How do we configure this with just one data control?
• If ADF libraries may split data control definitions
– Q: How to combine @ runtime with one instance and they can share state?
• If our application uses multiple different data control types
– Q: How to commit/rollback as a group?

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ADF Data Controls Challenges & Solutions
• If transactions are logically mapped to navigating groups of web pages
– Q: How do we map the data control transaction to these boundaries?
– A: Task flows allow you to define groups of pages/fragments and task flows
• If we need to support separate transactions per session
– Q: How do we configure this with just one data control?
– A: Task flows can create a new data control or share an existing one
• If ADF libraries may split data control definitions
– Q: How to combine @ runtime with one instance and they can share state?
– A: Intelligence is built in to combine data controls at runtime
• If our application uses multiple different data control types
– Q: How to commit/rollback as a group?
– A: Task flows track the data controls attached as a group

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ADF Data Controls Challenges & Solutions
• If transactions are logically mapped to navigating groups of web pages
– Q: How do we map the data control transaction to these boundaries?
– A: Task flows allow you to define groups of pages/fragments and task flows
• If we need to support separate transactions per session
– Q: How do we configure this with just one data control?
– A: Task flows can create a new data control or share an existing one
• If ADF libraries may split data control definitions
– Q: How to combine @ runtime with one instance and they can share state?
– A: Intelligence is built in to combine data controls at runtime
• If our application uses multiple different data controls
– Q: How to commit/rollback as a group?
– A: Task flows track the data controls attached as a group
Answered in the previous presentations

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ADF Data Controls Challenges & Solutions
• If transactions are logically mapped to navigating groups of web pages
– Q: How do we map the data control transaction to these boundaries?
– A: Task flows allow you to define groups of pages/fragments and task flows
• If we need to support separate transactions per session
– Q: How do we configure this with just one data control?
– A: Task flows can create a new data control or share an existing one
• If ADF libraries may split data control definitions
– Q: How to combine @ runtime with one instance and they can share state?
– A: Intelligence is built in to combine data controls at runtime
• If our application uses multiple different data controls
– Q: How to commit/rollback as a group?
– A: Task flows track the data controls attached as a group
Answered in the this presentation

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ADF Data Controls Challenges & Solutions
• If transactions are logically mapped to navigating groups of web pages
– Q: How do we map the data control transaction to these boundaries?
– A: Task flows allow you to define groups of pages/fragments and task flows
• If we need to support separate transactions per session
– Q: How do we configure this with just one data control?
– A: Task flows can create a new data control or share an existing one
• If ADF libraries may split data control definitions
– Q: How to combine @ runtime with one instance and they can share state?
– A: Intelligence is built in to combine data controls at runtime
• If our application uses multiple different data controls
– Q: How to commit/rollback as a group?
– A: Task flows track the data controls attached as a group
Answered in the next presentation

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Task Flow Transaction and Data Control Scope Options
<?xml version="1.0" encoding="ISO-8859-1" ?>
<adfc-config xmlns="http://xmlns.oracle.com/adf/controller"
version="1.2">
<task-flow-definition id="task-flow-definition">
<transaction>
<new-transaction/>
</transaction>
<data-control-scope>
<isolated/>
</data-control-scope>
<use-page-fragments/>
</task-flow-definition>
</adfc-config>

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Shared Data Control Scope
• “Share data controls with calling task flow”
• Shared
– Between calling & called task flows
– If data controls are of the same
name and type
– Only one instance of the data
control will be created & shared
– And view objects sharing:
• Current row indicators
• Edit the same records
• One database connection

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Isolated Data Control Scope
• Don’t’ “Share data controls with calling task flow”
• Isolated
– Regardless two instances of the
data control
– Allows disparate data control
transactions
– Separate view objects
• No record coordination
• Isolated record editing
• Separate connections

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Our system provides the user access to two
isolated instances of the same data control
simultaneously, and we're now infrequently
hitting row lock errors.
Why and what’s the solution?
Exercise
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Shared Data Control Scope: To
2
1
3
4

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Shared Data Control Scope: Returning
1
3
4
2

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Isolated Data Control Scope: To
1
2
43

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Isolated Data Control Scope: Returning

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Isolated Data Control Scope: Returning
1
2
4
5
3
6

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Every isolated task flow means
separate data control instances,
more memory consumed, and if
using ADF BC more database
connections consumed.

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Rules for Sharing Data Controls
• Data control must be in same data control frame
• Same data control type – eg. ADF BC, EJB, WebService
• Across ADF Libraries
– At design time if same data
control comes from two
different ADF libraries, if they
have the same name they can
also share

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Conclusion
• The data control scope allows task flows to share
or create separate instances of data controls
• If shared they will share a transaction and state
• If isolated they will have their own transaction and state
• Isolated makes sense when parts of the application state must
be kept separate and independent
– But does have an overhead of extra memory and (for ADF BC) database
connections
– And you lose sharing state (such as current iterator positions) across
separate instances of the same view object

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Further Reading
Essential to view the next slides on
Task Flow Transaction Options

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