15 Component Events

8/3/2019 15 Component Events

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Section 15

ADF Faces Component Events

and Validation

15


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Using Event Listeners

Ive been clicked!

Does anyone care?YesIm listening!

Now Ill get to work

Event Source

Event Object

Event Listener


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Responding to Action Events

Command components raise action events.

Code to respond to the action event can be in thebacking bean or external class.

Stub code is generated by JDeveloper ondemand.

The action is registered in the page source.

Action events are called in the Invoke Application

phase of the life cycle. Action methods are the last to execute after

other listeners, such as valueChange events.


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Creating Action Methods

To create an action method:

Invoke the action binding

editor

Choose existing bean and

method, or create new

JDeveloper:

If the bean does not exist, creates Java class and registers as a managed bean

If the method does not exist, creates a method stub in the managed bean

class

Adds the method to the action property of component

Add your own code.

Action methods return a String outcome.


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Using Action Listeners

Action listeners:

Contain code to respondto an action

Do not return a value

Execute after valuechange listeners

Action methods:

Are used for navigation

Return a String outcome

Execute last

Action listeners differ from action methods:

Both can be initiated bythe same action, such as

a button click.


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Value Change Events

Input components raise value change events.

Code for the value change listener can be in thebacking bean or external class.

Stub code is generated by JDeveloper. The value change event is registered in the page

source.

Value change events are processed in the InvokeApplication phase of the life cycle.

Value change events fire before action events.


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Listening for Value Change Events

Select the input component in the visual editor.

Edit the valueChangeListener property and select abean and method, or create a new one.

JDeveloper: Creates the method in the managed bean if it doesnt

already exist

Adds the method to the valueChangeListenerproperty in the page source

Add your code.


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Event and Listener Execution Order

The order in which the events and listeners fire is:

1. Validator (managed bean method that performs validationon the components value)

2. Value change listener (managed bean method to handle

value-change events)3. Action listener (managed bean method to handle action

events)

4. Action method(managed bean

method to return alogical outcomeString that is usedin navigation)


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ADF Faces Enhanced Event

Handling

ADF Faces adds to JSF event handling by

providing:

Partial page rendering (PPR)

JavaScript


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Other ADF Faces Events

Property Inspector of ADF Faces components

displays appropriate event listeners:


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Validation

Fusion Application Development with

Oracle JDeveoper 11g and Oracle ADF


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Validation Event PointsBrowser

Client side validations

Faces Validators

Backing Bean

Validations

ADF Model Validators

ADF BC Validations

Used for immediate feedback.

Useful when ADF BC is not used.

Final line of defense.


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Handling Validation Exceptions

Default behavior:

Exceptions bundled and returned to client

If posted, transactions are rolled back

Error message(s) displayed on JSF page

You can change default behavior by:

Creating custom exception handler

Changing how lifecycle reportsexceptions

Customize page exception handling


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JavaServer Faces Validators

Validation can be performed through

Separate validator components (classes), which

provide a high degree of reusability

Backing bean code Simpler to understand as code is co-located with the subject

But not reusable

JSF RI provides default validator components

No client-side validation code generated (such as JavaScript)

Multiple validators can be used on one input item


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Using ADF Faces Validation

ADF Faces validation:

Provides client-side validation

No server round trip needed

Types of ADF Faces validation:

Component

Default


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Using ADF Faces Component

Validation

ADF Faces component validation:

Is implemented by setting certain component

attribute values

Can include error messages for required

attribute

Messages can use parameters

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15 Component Events