Oracle JDeveloper 10g Build Applications with ADF Instructor Guide - Volume 2.pdf

8/15/2019 Oracle JDeveloper 10g Build Applications with ADF Instructor Guide - Volume 2.pdf

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D16975GC10

Production 1.0

May 2004

D39415

Oracle JDeveloper 10g: Build

Applications with ADF

Instructor Guide • Volume 2


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Copyright © 2004, Oracle. All rights reserved.

This documentation contains proprietary information of Oracle Corporation. It is

provided under a license agreement containing restrictions on use and disclosure and

is also protected by copyright law. Reverse engineering of the software is prohibited.

If this documentation is delivered to a U.S. Government Agency of the Department of

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Use, duplication or disclosure by the Government is subject to restrictions for

commercial computer software and shall be deemed to be Restricted Rights software

under Federal law, as set forth in subparagraph (c)(1)(ii) of DFARS 252.227-7013,

Rights in Technical Data and Computer Software (October 1988).

This material or any portion of it may not be copied in any form or by any means

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If this documentation is delivered to a U.S. Government Agency not within the

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The information in this document is subject to change without notice. If you find any

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Oracle Corporation, 500 Oracle Parkway, Box SB-6, Redwood Shores, CA 94065.Oracle Corporation does not warrant that this document is error-free.

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Authors

Gary Williams

Lynn Munsinger

Patrice Daux

Technical Contributors

and Reviewers

Jeff Gallus

Pam Gamer

Duncan Mills

Publisher

Joseph Fernandez


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Preface

I Introduction

Objectives I-2Course Overview I-3

1 Oracle Application Development Framework

Objectives 1-2

J2EE Platform 1-3

Benefits of the J2EE Platform 1-5

J2EE Platform: Architecture Details 1-6

Building J2EE Applications 1-7

What Is Framework-Based Application Development? 1-8

Understanding Framework-Based Application Development 1-9

Oracle Application Development Framework 1-10Visual and Declarative Development 1-11

Design Patterns 1-12

Model-View-Controller Architecture 1-13

MVC Structure 1-14

What Is the Model? 1-15

The Model Layer 1-16

Components of the Model Layer 1-17

What Is the Controller? 1-18

Struts in JDeveloper 1-19

Controller: Summary 1-20

What Is the View? 1-21

View Concept 1-22

View Technologies in Oracle JDeveloper 10g 1-23

View: Summary 1-24

ADF Technology Stack 1-25

ADF: Summary 1-26

Summary 1-27

2 ADF Development Process

Objectives 2-2

Project Technology Scopes 2-3 ADF Technology Stack 2-4

A Sample Application 2-5

Building an Application 2-6

Application Workspaces 2-7

Application Workspace Templates 2-8

Contents

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Creating an Application Workspace 2-9

New Application Workspace 2-10

Design the Business Services for the Model: ADF Business Components 2-11

Design the Application Page Flow 2-13

Create the Page Flow 2-14

Create JSP Pages 2-15Using the Visual Editors 2-16

Databinding: Example 2-17

Adding HTML to Enhance the User Interface 2-18

Results 2-19

Summary 2-20

Practice 2-1: Overview 2-21

3 Getting Started with ADF Business Components

Objectives 3-2

ADF Technology Stack 3-3

What Are ADF Business Components? 3-4

ADF Business Components 3-5

Benefits of ADF Business Components 3-6

Business Components 3-7

Business Domain Components 3-8

Data Model Business Components 3-9

Business Components Model 3-10

Building a Business Components Model 3-11

Creating a Database Connection 3-12

Creating ADF Business Components: Entity Objects 3-13

Creating ADF Business Components: View Objects 3-16Creating Custom Views 3-18

Selecting the Attributes 3-19

Creating an Application Module 3-20

Testing the Business Components 3-21

Summary 3-22


4 Building Business Logic

Objectives 4-2

Business Logic Validation 4-3

Implementing Validation in the Business Services Tier 4-4Entity Object: Overview 4-5

Entity Object 4-6

Creating an Entity Object 4-7

Entity Object Wizard 4-8

Files Generated for the Customers Entity Object 4-9

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Optional Files Generated for the Customers Entity Object 4-10

Using the Business Components Modeler for Entity Objects 4-11

Assigning an Initial Value to an Entity Attribute 4-13

Mapping an Attribute to a Database Sequence 4-14


Practice 4-1 4-16 Adding Validation 4-19

Declarative Validation Rules 4-20

Li st Val i dat or : Example 4-21

Adding Uni queKeyVal i dat or to an Entity 4-22

Domains 4-23

Domains: Example 4-24

How to Create a Domain 4-25

How to Use a Domain 4-26

Summary 4-27


5 Exposing Business Data

Objectives 5-2

View Object in the ADF Architecture 5-3

Overview 5-4

View Objects 5-5

Interaction Between Views and Entities: Retrieving Data 5-6

Interaction Between Views and Entities: Updating Data 5-7

Synchronization of View Objects 5-8

Creating a View Object Using the View Object Wizard 5-9

Classes Related to View Objects 5-10Files Generated for the Li neI t emVi ewView Object 5-11

Example of a View Object 5-12


Practice 5-1 5-14

Calculated Attributes in Views 5-17

View Links 5-18

Traversing Links 5-19

Using the Business Components Modeler for View Objects (I) 5-20

Using the Business Components Modeler for View Objects (II) 5-21

Application Module in the ADF Architecture 5-22

Application Modules 5-24

Creating an Application Module Using the Application Module Wizard 5-25

Using the Business Components Modeler for an Application Module (I) 5-26

Using the Business Components Modeler for an Application Module (II) 5-27

Summary 5-28


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6 Adding Custom Validation

Objectives 6-2

Overview 6-3

Adding Validation to an Entity 6-4

Validating Attributes 6-5

Creating a Met hodVal i dat or for an Attribute 6-6Utilizing Typesafe Methods 6-8

Validating Entity Objects 6-9

Call Ent i t yI mpl Methods 6-11

Validation Order 6-12

Associations 6-13

Association Example 6-15

Accessor Methods 6-16

Association Types 6-17

Determining the Association Type 6-18

Creating Entity Associations 6-19Traversing Associations: Destination to Source 6-23

Traversing Associations: Source to Destination 6-24

Summary 6-25


7 Providing for Efficient Queries

Objectives 7-2

Overview 7-3

Expert Mode View Objects 7-4

Mapping Attributes in Expert Mode 7-5

Maintaining Attribute Mappings in Expert Mode 7-6SQL-Based View Objects 7-7

Creating a SQL-Based View Object 7-8

Implementing Custom Methods 7-9

Expose Methods to the Client Application 7-10

Creating a Test Client 7-11

Instantiating an Application Module 7-12

Instantiate a View Object and Output Data 7-13

Calling Custom Methods 7-14

Setting Parameters for the Wher e Clause 7-15

Assigning Values to Queries with Parameters at Run Time 7-17

Creating a Test Client – Sample Code 7-18

Creating a View Object at Run time 7-20

Finding Data by a Row Key 7-22

Summary 7-23


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8 Making the Model Secure

Objectives 8-2

Goals of J2EE Security Architecture 8-3

Overview of J2EE Security Architecture 8-4

Java Authentication and Authorization Services 8-5

JDeveloper, JAAS, and Securing the ADF Model 8-8Enabling JAAS Authentication for ADF Business Components 8-9

The j bo. secur i t y. enf or ce Application Property 8-10

Setting Entity Permissions 8-11

Entity Privileges 8-12

Attribute Permissions 8-13

Using the Business Components Browser 8-14

Testing Entity and Attribute Authorization 8-15

Summary 8-16


9 Controlling an Application with Struts

Objectives 9-2

The Controller 9-3

ADF Implements MVC Using the Struts Controller 9-4

Purpose of a Controller 9-5

Example: Page Flow Without a Controller 9-6

Example: Page Flow with a Controller 9-10

What Is Struts? 9-12

Struts Components 9-13

Struts Components Flow 9-15

Struts Components: The Controller Servlet 9-16Struts Components: The Configuration file 9-17

Struts Components: Actions 9-18

Struts Components: Act i onFor ms (Form Beans) 9-19

Struts Components: Tag Libraries 9-20

Application Resources File 9-21

Internationalizing Your Application 9-22

Struts in Oracle JDeveloper 10g 9-23

Struts Configuration File 9-24

Defining the st r ut s- conf i g. xml File Content 9-25

Creating a Page Flow Diagram 9-28

Struts Components: Actions 9-29

Struts Components: Pages and Page Forwards 9-30

Struts Components: Forwards and Links 9-31

ADF Components: DataAction and DataPage 9-32

Summary 9-33


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10 Building ADF View Components

Objectives 10-2

What Is a JSP? 10-3

JavaServer Pages in ADF 10-4

Example: JSP 10-5

Basic JSP Elements 10-6JSP Directives 10-7

JDeveloper and JSPs 10-10

The Visual Editor 10-11

What Are Custom Tags? 10-12

Utilizing Tag Libraries 10-13

JSP Standard Tag Library 10-14

Struts Tags 10-15

Data Binding Tags 10-16

Utilizing the Data Control Palette 10-17

How Data Is Displayed 10-18View Object Control Types 10-19

View Object Item Control Types 10-20

Operations 10-21

Customizing Controls 10-22

JSP Versus UIX 10-23

Summary 10-24

Practice 10-1: Overview

11 Customizing Actions

Objectives 11-2

Struts Configuration File 11-3Creating the Action Class 11-4

Default Code of an Action 11-5

Forwards 11-6

Act i onFor war d of an Action Class 11-7

Creating Global Forwards 11-8

Form Beans 11-9

Creating a Static Form Bean 11-11

Example: Static Form Bean 11-12

Dynamic Form Beans 11-13

Creating a Dynamic Form 11-14

Using the Bean in an Action 11-15

Sample Page Flow 11-16

Sample Page Flow: Struts Elements 11-17

Sample Page Flow: Form Bean 11-19


Sample Page Flow: Action Class 11-22

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Form Beans, Data Actions, and Data Pages 11-24

Summary 11-25


12 Using ADF Struts ComponentsObjectives 12-2

What Are Data Actions? 12-3

What Are Data Pages? 12-4

Utilizing Data Pages 12-5

Creating Data Pages 12-6

Creating the View Component 12-7

Displaying Data 12-8

Modifying the Iterator 12-10

Adding Methods to Data Actions 12-11

Adding Methods to Data Pages 12-12

Navigating in Data Pages 12-13

Data Action Life Cycle 12-14

The Data Action Lifecycle 12-15

Customizing Data Actions 12-16

Data Action Events 12-17

on Example: Built-in Events 12-19

on Example: Custom Events 12-20

Forwards and Events in ADF Applications 12-21

Summary 12-22


13 Adding Validation and Error Handling

Objectives 13-2

Overview of Validation 13-3

Need for Validation 13-4

Client-Side Validation 13-5

Form Bean Validation Method 13-6

Creating the Error Message 13-7

Printing Errors in the JSP 13-8

Validating Actions 13-9

Creating a Validation Class 13-10

The execut e( ) Method 13-11Validation Results 13-12

Struts Validator 13-13

Setting Up the Struts Validator 13-14

Utilizing the Struts Validator 13-15

val i dat i on. xml : Example 13-17

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Struts Validator Output 13-18

Exception Handling 13-19

JavaScript 13-20

Enhancing the View 13-21

Summary 13-22


14 Enhancing the User Interface

Objectives 14-2

Modifying Visual Component Properties 14-3

Using the Toolbar to Format Objects 14-4

Using the Property Inspector 14-5

Adding Images to JSPs 14-6

Using Style Sheets 14-7

Editing Default Style Sheets 14-8

Creating a New Style Sheet 14-9

Editing Style Sheets 14-10

Adding a Style Sheet to the

Component Palette 14-11

Applying a Style Sheet to a Page 14-12

Adding Buttons to a JSP 14-13

Adding Data Control Buttons 14-14

Adding Navigation Buttons 14-15

Adding Form Action Buttons 14-16

Supplementing Button Functionality 14-17

Using Expression Language 14-18

Using EL Attributes 14-19Using EL Literals and Operators 14-20

Using EL Implicit Objects 14-21

Using EL to Customize a Page 14-22

Summary 14-23

Practice 14: Overview 14-24

15 Adding JAAS Security to the Client

Objectives 15-2

JAAS Provider 15-3

Defining Security Needs 15-4

Oracle JAAS Implementation: JAZN 15-5Client Authentication 15-6

Client Authorization 15-7

Basic Authentication Scenario 15-8

Adding JAAS Security to an Application 15-9

Adding Authorization Information to Struts 15-10

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web. xml Properties 15-11

web. xml Results 15-12

Adding Users and Roles 15-13

Adding Users 15-14

Managing Roles 15-15

Selecting a Specific j az n- dat a. xml File 15-16Running the Application 15-17

Summary 15-18

16 Building ADF UIX View Components

Objectives 16-2

Why ADF UIX Technologies? 16-3

What are ADF UIX Technologies? 16-4

How Do ADF UIX Technologies Work? 16-5

UIX XML Page Layout 16-6

Interface Nodes 16-7

How Is It coded? 16-8

Support for Internationalization 16-9

User Interface Components 16-10

Modular Declarative Design 16-11

Creating a UIX XML Page 16-12

Company and Product Branding 16-13

Page Tabs 16-14

Global Buttons 16-15

Page Footers 16-16

Designing with the Visual Editor 16-17

Coding with the XML Editor 16-18UIX XML Page at Run Time 16-19

Adding Data to the Page 16-20

Design Time Data Components 16-21

Data Binding in the Visual Editor 16-22

Run-Time UIX XML Page with Data Binding 16-23

Summary 16-24

Practice 16: Overview 16-25

17 Deploying an ADF Application

Objectives 17-2

Overview 17-3Overall Considerations for Deployment 17-4

J2EE Archive Format 17-5

Deploying to a Web Server 17-6

Deploying to OC4J 17-7

Install OC4J 17-8

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Start the OC4J Server 17-9

Creating an OC4J Connection 17-10

Creating a Deployment Profile 17-12

Deploying to OC4J 17-13

Running Applications 17-14

Customizing Deployment 17-15Summary 17-16


Appendix A: Course Schema

Appendix B: Practice Solutions

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Customizing Actions

Schedule: Topic Timing

Lecture 60 minutes

Practice 30 minutes

Total 90 minutes


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Oracle10 Forms Develo er: Bui ld Internet A l icat ions 11-2Oracle JDevelo er 10 : Bui ld A l icat ions with ADF 11-2

11-2 Copyright © 2004, Oracle. All rights reserved.

Objectives

After completing this lesson, you should be able to

do the following:

• Describe the Struts XML elements and structure

• Describe the anatomy of an action

• Use the execute method to enhance the behavior

of an action

• Describe the use of form beans

• Use a dynamic form bean

Objectives

In this lesson, you learn more about Struts components in order to create applications that use the

Struts framework to validate user input from an HTML form. You also learn how to create

applications that contain label references, so that labels can be populated at run time based on the

language settings of the client’s browser.


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Struts Configuration File

• Is XML type fi le

• Is the application resource descriptor

• Is used by the servlet to determine actions to

perform

Struts Configuration File

As you have already learned, the Struts Configuration file is the road map of the application.

This is where the logical flow of the application is defined by using XML syntax. It describes

Form Beans, Actions, ActionMappings, resource bundles, data sources, and other parameters.

Note that you can create one or more configuration files per application. However, by default,

JDeveloper creates one configuration file namedst r ut s- conf i g. xml . The name andlocation of the file are specified in the web. xml file for the application.


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Creating the Action Class

• In the context menu, select “ Go to Code.”

• Or, double-click the action.

• Specify a name for the action.

/auth

Creating an Action

An action is an adapter between the contents of an incoming HTTP request and the

corresponding business logic that should be executed to process this request. The action package

is the core of the Struts framework, representing the controller layer of a Model-View-Controller(MVC) model. All actions are subclassed from or g. apache. st r ut s. act i on. Act i on.

The XML definition of an action in the st r ut s- conf i g. xml file is:

The path name appearing on the Page Flow Diagram is a logical name, where the name specified

in the Create Struts Action dialog box is the physical name.


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Default Code of an Action

public class AuthUserAction extends Action{

/* This is the main action called from the Struts

framework.*/

public ActionForward execute(

ActionMapping mapping,

ActionForm form,

HttpServletRequest request,

HttpServletResponse response)

throws IOException, ServletException

{

return mapping.findForward("success");

}

}

Default Java Code of an Action

When creating an action, JDeveloper generates Java code as shown above.

In this example, Aut hUser Act i on extends the Struts act i on class. The execut e( )

method is where you add your own code for customization, and then return an

Act i onFor ward (also called a page forward) to continue the flow of the application.


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Forwards

Forwards can be defined:

• By using the Page Flow

Diagram

• In the XML file

• In the Structure pane

/authUser

success

failure

/page1

/page2

Forwards

Forwards control the flow of an application. One or more forwards are generally defined within

the element in the XML and these, along with any global forwards (defined in thesection of the XML), are valid places for that action to forward to.


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ActionForward of an Action Class

• The return parameter from ActionForward

specifies where to send control.

• The default naming of a single forward issuccess.

• The execute() method can be customized:

– Additional code can be added.

– Other forwards can be specified.

– Appropr iate forward is done on conditional testing.• The forward name represents a logical name.

• A forward can also be a global forward.

ActionForward

The programmer has to return a reference to a forward from the execut e( ) method in theaction. This is done by using the f i ndFor war d( ) method, which accepts the name of the

forward to return to.


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Creating Global Forwards

• A global forward is just like any forward, but it can

be accessed by any action.

• The global forward is defined in the config file.

• The global forward is specified in the action class.

return mapping.findForward("help");

Global Forwards

A global resource, such as a global forward or a global exception, can be used at any time by any

resource.

The links to a global forward are not represented on the page flow.


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Form Beans

User Name

Password

Logon

logonBean

Submit

Logon

authUser

menu

Populates

Form Beans

Form beans are associated with one or more actions. When a page is submitted to the action, the

Struts controller matches parameters from the request object with fields in the form bean class

and populates the bean.

The developer is passed the form bean reference as a parameter to the execut e( ) method ofthe action class, and the values are accessible through get() methods. This saves the developer

from having to query the request. More importantly, the bean can be populated before a page is

displayed and the fields in the page are prepopulated with the relevant fields from the bean that

match the field names in the HTML form—so the process works both ways.


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Form Beans

• A form bean is used to transport data between a

page and an action.

• Can be static:

– Is defined in a FormBean class

– Contains set(), get(), and reset() methods for

each field

– Contains a validate() method for verifying user

input

• Can be dynamic:

– Each field specified in struts.config.xml

– Does not require Java code

Form Beans (continued)

You can create “static” beans, which are your own JavaBeans that extend theAct i onFor m

class and have getters and setters for each field that you want to support. Or, you can do thedeclaration in the Struts XML by using a dynamic bean calledDynaAct i onForm, and without

writing code.


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Creating a Static Form Bean

• Create an action in the Page Flow Editor.

• Right-click and select “ Go to Form Bean.”

• Specify a name (suffix the name with “ Form” ).

• A new icon is displayed.

/authUser

/authUser

Creating a Form Bean

The example above illustrates the creation of a static form bean. This is specified in the

st r ut s- conf i g. xml file as:

The main advantage of using the static form bean is that you can write custom validation code to

check the user input and reset code to initialize the bean. If you do not need these features, then a

dynamic bean is the best.


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Example: Static Form Bean

public class AuthUserActionForm extends ActionForm

{

String username;

public String getUsername()

{ return username; }

public void setUsername(String newUsername)

{ username=newUsername; }

public void reset( …

public ActionErrors validate( …

}

Example: Static Form Bean

In this example, the static bean contains an attribute named “username,” and contains a get and

set method for the attribute. Note that if the val i date( ) method throws an error, the error is

automatically displayed in the JavaServer Page (JSP) that called the page, assuming that theStruts tag exists in the page.

The developer is passed the form bean reference as a parameter to the execut e( ) method ofthe action class. The values are accessible through get() methods. This saves the developer

from having to query the request. More importantly, the bean can be populated before a page is

displayed, and the fields in the page are prepopulated with the relevant fields from the bean thatmatch the field names in the HTML form—so the process works both ways.


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Dynamic Form Beans

• This is an alternative way for an action to have

access to incoming fields from a page.

• The form bean class is not needed.

• There is no need for getter and setter methods.

• The field names are specified in the struts-

config.xml file.

• New f ields can be added dynamically.

Dynamic Form Beans

The dynamic version of a form bean is defined by using the correct type

(org. apache. st r ut s. act i on. DynaAct i onForm) in the st r ut s- conf i g. xml fileand then creating one tag per field in the dynamic bean class. You can

also define an initial value for each of these fields. There is no bean-level validation with adynamic bean. To include bean-level validation, use theexecut e( ) method of the action.


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Creating a Dynamic Form

1. Create a form bean from the Structure pane.

2. Specifyorg.apache.struts.action.DynaActionForm

as the type for the bean.

3. Create a new form property for each field.

Creating a Dynamic Form

To create a dynamic action form from the Page Flow Diagram, right-click the action, select “Go

to Code,” and specify a name. Then, specify the type for the bean asorg. apache. st r ut s. act i on. DynaAct i onForm, and create a

element for each field in the form.


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Using the Bean in an Action

• Using a static bean:

– Create and cast the ActionForm type

– Use the getXxx() method

• Using a dynamic bean:

– Cast the form object passed to the execute()method to a DynaActionForm type

AuthUserActionForm authForm = (AuthUserActionForm) form;

String username=authForm.getUsername();

String

username=(String)((DynaActionForm)form).get("username");

Using the Bean in an Act ion

The bean allows your action class to have access to the input fields. In the static bean, the

username is retrieved by using the get User name( ) method. In the dynamic bean, theusername is retrieved by casting the “username” object to aDynaAct i onFor mtype.


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Sample Page Flow

success

failure


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Sample Page Flow: Struts Elements


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Sample Page Flow: Form Bean

User Name

Password

Logon

logonBean

Submit

success

failure

Logon

authUser

menu


When the user clicks the Logon button, the controller resolves that the target of the form on the

page is aut hUser . do (the . do extension tells the servlet container that this is a StrutsAction). Because the aut hUser action has an associated bean called l ogonBean (defined by

the name attribute), the controller looks for the bean class (static) or bean definition (dynamic)named l ogonBean.


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Sample Page Flow

Passed to

User Name

Password

Logon

logonBean

Submit

Populates

successsuccess

failure

Logon

authUser

menu

Sample Page Flow

The Struts servlet reads the request and looks at the metadata to create a bean populated with the

data out of the input fields in the page. Next, it calls the Aut hAct i on class, which is defined by the t ype attribute in the action definition, and passes the populated form bean to theexecut e( ) method.


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Sample Page Flow: Action Class

public ActionForward execute(ActionMapping mapping,

ActionForm form, HttpServletRequest request,

HttpServletResponse response) throws IOException,

ServletException

{

DynaActionForm LAF = (DynaActionForm) form;

String un = (String)LAF.get("username");

String pw = (String)LAF.get("password");

if (un.equals("Scott")) {


} else

return mapping.findForward("failure");

}

Sample Page Flow: Action Class

Generally, when you write a Struts action, you simply extend the base action and implement a

custom execut e( ) method. The framework passes everything you need into that method,

including:

• A reference to the Struts metadata (ActionMapping), so that you can resolve forwards

• The populated form bean (static or dynamic)

• A reference to the request (and, therefore, the session as well)

• A reference to the response object, so that you can save further data, such as errors, for the

response.In this case, the bean with the user-supplied username and password is passed into the

execut e( ) method. The checkAut h method (not shown) performs the custom validation.

If the validation succeeds, f i ndForward( ) is used to look up the next place to go based on

the “success” forward name. The reference to the failure forward is returned if the validation

fails.


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Sample Page Flow

Passed to

User Name

Password

Logon

logonBean

Submit

Populates

success

failure

Logon

authUser

menu

Sample Page Flow

Lastly, the Struts controller forwards the user to the required page or action, and the new page is

displayed in the browser. The simple page flow example is complete.


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Form Beans, Data Actions, and Data Pages

• ADF creates a form bean automatically when you

create:

– Data actions

– Data pages

• The ADF Form Bean is called a DataForm.

• DataForms do not require custom code:

– No static form bean class is needed.

– No dynamic form bean declaration is needed.• ADF uses these objects to manage form data.

Form Beans, Data Actions, and Data Pages

Data actions and data pages use a specialized form bean for managing form data. This bean is

created automatically when you create a data action or data page. No further coding or

declaration is required, because ADF builds the form bean for you. This specialized form bean is

named DataForm.


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Summary

In this lesson, you should have learned how to:

• Describe the Struts XML elements and structure

• Describe the anatomy of an action

• Use the execute method to enhance the behavior

of an action

• Describe the use of form beans

• Use a dynamic form bean

Summary

In this lesson, you should have learned the XML syntax for the content of thestruts-conf i g. xml file. Additionally, you should have learned about advanced Struts components,

such as actions and form beans, and how to support internationalization of a Struts application.


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This practice covers the following topics:

• Using the Page Flow Diagram

• Adding data actions

• Adding data pages

• Creating form beans


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Practice 11-1

In this practice, you create a form bean to hold logon information. That logon information is

passed to an action that performs authentication and returns a customer name if the validation

succeeds.

Start JDeveloper, and open thepr act i ce11 workspace.

1. Create form beans.

a. Open the Page Flow Diagram.

b. In the Structure pane, create a new Form Bean.c. In the Property pane, specifylogonBean as the name and set the type to

org. apache. st r ut s. act i on. DynaAct i onForm.d. In the Structure pane, select thelogon bean and create a new Form Property.

e. In the Property Inspector, set the name property to l ast Name and leave it as aSt r i ng.

f. Create a second Form Property for cust omer I d (leave it as a St r i ng).

2. Create a new view object that validates the customer logon. This view object will accept

two parameters and query the customers table for a combination of both

cust omer Last Name and cust omer I d.

a. Create a view object. Name it AuthenticateView. Remember to create the view

object in the Model project.

b. Select customers as the entity object.

c. Select cust omer I d, cust Fi r st Name, and cust Last Name as the attributes.d. Add a WHERE clause that compares the upper of cust Last Name with the upper of

a parameter AND compares cust omer I d with a second parameter.

e. Make sure to select the Use ? Style parameters check box if you are using the above

syntax.

f. In step 6 of 6, select the Generate Java File option for the View Row class.

g. Click Finish to validate.

h. Add the view toSalesAppModule and remove “1” from the instance name.

SELECT Customers.CUSTOMER_ID,

Customers.CUST_FIRST_NAME,

Customers.CUST_LAST_NAME

FROM CUSTOMERS Customers WHERE upper(Customers.CUST_LAST_NAME)= upper(?)

and Customers.CUSTOMER_ID= ?


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Practice 11-1 (continued)

3. Create a data action.

a. Open the Struts Page Flow Diagram.

b. Drag the Data Action icon next to the logon page.

c. Change the name to /authenticateUser.

4. Create a new method to validate customer’s logon by using the view you just created.

a. Select the SalesAppModule node in the Applications Navigator.

b. In the Structure pane, double-click theSal esAppModul eI mpl . j ava node.c. In the Source Editor, create a new method that has the following characteristics:Its signature is:

public String findCustomers(String lastName, String customerId)

(The return parameter is a string of Fi r st Name and Last Name concatenated.)

Note: The code for this method is at the end of this practice.

d. Import any classes necessary.

e. Compile the class, and correct any errors that you may have.

5. Make the method available to client applications.

a. Double-click SalesAppModule to open the Module Properties Wizard.

b. Select the Client Interface node.c. Move the findCustomersmethod from Available to Selected, and click OK.

6. Add the method to theAuthenticateUser data action.

a. Open the Page Flow Diagram.

b. From the Data Control Palette, open theSaleAppModuleDataControlnode.c. Open the Operations node and select the f i ndCust omer s( ) method.

d. Drag the method to theauthenticateUser data action.

7. Set the parameter properties of the data action.

a. In the Structure pane, open the /authenticateUser pane.

b. Select the paramNames[0] node.c. In the Property Inspector, change the value key to

${sessionScope.lastName}.

d. Select the paramNames[1] node.

e. In the Property Inspector, change the value key to${sessionScope.customerId}.

f. Select the resultLocation node.

g. In the Property Inspector, change the value key to${sessionScope.customerName}.


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8. Associate the logon page to the data action.a. Open the logon page. b. Select the Source Editor.c. Above the tag, insert the following:

d. Close the form tag after the tag.e. Remove the link to the categories page that you added in an earlier practice.

f. Right-click the logon page on the Page Flow Diagram, and select the RefreshDiagram from Page option. A page link should appear between logon andauthenticateUser.

g. Create a forward going fromauthenticateUser to categories. The Struts diagramshould look something like the diagram below:

9. Run the application starting at thewelcome page. Try to log on with the following valuesof Cust omer Last Name and Cust omer I d:Wel l es 101

Paci no 102 Tayl or 10310. You will enhance this validation in a later practice.


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SalesAppModuleImpl.java

public String findCustomers(String lastName, String

customerId)

{

ViewObjectImpl vo = this.getAuthenticateView();vo.setWhereClauseParam(0,lastName);

vo.setWhereClauseParam(1,customerId);

vo.executeQuery();

AuthenticateViewRowImpl row =

(AuthenticateViewRowImpl)vo.first();

String customerName = null;

if (row != null)

{

customerName = row.getCustFirstName() + " " +

row.getCustLastName();

}

return customerName;

}


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Using ADF Struts Components


Lecture 30 minutes

Practice 45 minutes

Total 75 minutes


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Objectives

After completing this lesson, you should be able to dothe following:

• Describe data actions and data pages

• Customize data actions and data pages to

enhance the behavior of an application

• Use data actions to access mult iple types of

business services

• Describe the relationship between databoundpages and data pages

Objectives

Databound applications that contain Oracle ADF business services are created by using data

actions. This lesson discusses how data actions are created, customized, and utilized in a

databound application.


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What Are Data Actions?

Data actions are an extension of the action class,which:

• Are provided with Oracle ADF

• Provide access to business services, such as

business components

• Prepare the data and make it available for pages to

consume

What Are Data Actions?

Data actions are an extension of the Struts Act i on class. By default, they provide access to

business services, such as view object business components. Data actions are created in the

Struts Page Flow Diagram and customized by using the Data Control Palette, Structure pane, and

Property Inspector.


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-


What Are Data Pages?

Data pages are an extension of the DataAction class,

which:

• Are provided with Oracle ADF

• Combine a data action and a page forward

• Do not rely on forwards to forward application

data

• Simplify the Page Flow Diagram

What Are Data Pages?

Data pages are an extension of the Dat aAct i on class. They are a combination of a data action

and page forward. For example, if you have a customer view object and want to create a new

customer, you can create a data action based on “Customers” and a page forward based on the

same “Customers” view. Alternatively, you can create a data page based on the “Customers”

view and you have all the benefits of having the data controlled by a Struts controller

component, but with half the number of components.


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Utilizing Data Pages

To use a data page, perform these steps:1. Create the data page in the Page Flow Diagram.

2. Double-click to create the corresponding view

object (JSP, HTML, and UIX).

3. Define the Struts page flow as necessary.

4. Add business service methods to the data page as

necessary.

Utilizing Data Pages

To utilize a data page, create it in the Page Flow Diagram. Next, create the corresponding view

component by double-clicking the data page. Next, define the Struts page flow further if

necessary. For example, a browse form may have a link to an insertion form. Then, add methods

as necessary to the data page. These steps are discussed in detail in the slides that follow.


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Creating Data Pages

Drag a data page to

the Page Flow

Diagram. The struts-

config.xml file is

updated with the

data action.

/browseCustomer

Creating Data Pages

To create a data page in your application, drag a data page from the Component Palette to thePage Flow Diagram. The st r ut s- conf i g. xml file is updated automatically. Note that the

data page extends

oracl e. adf . cont r ol l er . st r ut s. act i ons. DataFor war dAct i on. In this case, a

data action for browsing the customers view object has been created. The page has not been

associated with a JavaServer Page (JSP) yet, so the data page icon has a caution symbol on the

Page Flow Diagram, and the parameter attribute is “unknown.” The name parameter is not the

name of the data page, but the name of the form bean used to transport data between thecontroller and the view. The “DataForm” bean specified is the generic ADF bean that is

automatically generated. The next step is to create the JSP that displays the data.


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Creating the View Component

Double-click the data page to createthe view component.

/browseCustomer

Creating the View Component

Double-click to create the view component. By default, the name of the data page is used as the

file name, with a .jsp extension, but this can be any view component. The parameter attribute is

updated to show the corresponding view component/ br owseCust omer s. j sp. Additionally,the modelReference property is set to br owseCust omer sUI Model , which is the name of the

file that the data page uses to initialize data and methods. The file is not created until data

controls are added to the view component.


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Displaying Data

To display data from the data page, add elements fromthe Data Control Palette:

• Bound Data

• Navigation

• Operations

The data controls associated with the data action aredefined in DataBindings.cpx (created automatically).

Displaying Data

The next step in utilizing data pages is to develop the JSP that contains the bound data. Utilize

the Data Control Palette to add data, navigation, and operations to the JSP. Note that the first

time you add a data control to the page, the mappings for all data controls are automaticallygenerated and contained in Dat aBi ndi ngs. cpx.


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Displaying Data

Select elements from the Data Control Palette and dragthem to the page:

…

Generated code

Displaying Data (continued)

To display data bound to a view object, select the view or attribute that you want to add to the

page, and select the appropriate Drag and Drop As value. In this example, a table for browsing is

desired, so the Cust omer sVi ewdata control is dragged as a read-only table to thebr owseCust omer s. j sp. This is exactly the same procedure as you have seen in a previouslesson. Note that for each page you bind data to, aUI Model . xml file is created to map theattributes. This uses the name defined in the model Ref er ence property value for the data

page.


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Modifying the Iterator

Click the UIModel icon in the Structure pane to locatethe iterator for the model. Then use the Property

Inspector to change the range size.

Modifying the Iterator

To modify the range size of the iterator, locate it by using the UIModel tab of the Structure pane.

You can then set the range size of the iterator as necessary in the Property Inspector. The iterator

provides access to a set of rows within a view object.

Instructor Note

If you set the range size to –1, the iterator returns the entire rowset. The default value is 10.


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Adding Methods to Data Pages

Drag and drop methods from theData Control Palette to add

methods to a data page:

setCurrentRowWithKey

Delete

Create

Adding Methods to Data Pages

As shown in the slide, the set Cur r ent RowWi t hKey method is added to the/ edi t Cust omer s data page to enable the data page to display only the currently selected

row. This method is also used to set the currency of the row before deleting the row.

A row is selected in the / br owseCust omer s data page by using a Select Row link, which

passes the current row’s key to a linked page or action. Additionally, the create and delete

methods are used as indicated, for creating new rows and deleting a selected row.


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Navigating in Data Pages

• HTML Form tag submits to itself, by default.• Change the action to the page that receives the

form data.

• Use the Property Inspector to change the value of

“action.”

Select the data page or

action that receives the

form data.

Navigating in Data Pages

When you draw a link between pages, you define where the page goes next. However, when you

create an input form by dragging a view object, the form is coded by default to submit to the

same page on which it resides. Thus, this must be changed to enable application flow. Change

the value of the action attribute in the Property Inspector to specify the receiving data page or

data action.


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Data Action Life Cycle

1. Initialize context

Get HTTP request Get binding info

2. Build event li st

3. Check for model bindings

4. Check if updates allowed

5. Process updates

6. Validate updates

7. Handle model and UI events

8. Invoke custom methods

9. Refresh binding cont rols

10. Dispatch to forward

Data Action Li fe Cycle

1. Initialize context. The first step handl eLi f ecycl e( ) performs is to initialize the

context. In a Model 1 application, the context is an instance of

oracl e. adf . cont r ol l er . l i f ecycl e. Li f ecycl eCont ext . In a Struts

application, the context is an instance of

oracl e. adf . cont r ol l er . st r ut s. act i ons. Dat aAct i onCont ext , asubclass of Li f ecycl eCont ext . In either case, handl eLi f ecycl e( ) calls the life-

cycle context initialize method. This sets the value of the associated request, binding

container, and life cycle in the context.2. Build event list. Next, handl eLi f ecycl e( ) builds the list of events to be performed

by retrieving them from the request object with the life-cycle method

bui l dEvent Li st ( ) .


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Data Action Events

Built-in operations are listed in the UIModel.xml file:

• Defined by:

– Dragging operation from the Data Control Palette

– Explicit creation in the Structure pane

• Invoked by:

– Button with the name “ event_” ,

for example, event_Commit.

– Hyperlink with a parameter “ event=< operation>” ,for example, event=Commit.

Data Action Events

Built-in operations are the operations such as next, last, insert, and so on, which are available for

an iterator and which can be dragged to a page as a button.

When you drag an operation to a page, a name is generated for the button, which is prefixed with

the string “event_”, followed by the name of the operation itself.

Events can also be passed as hyperlinks by using the URL parameter “event=”, again followed

by the name of the event.

This means that you can add hyperlinks on a JSP that trigger events. You can also add buttons to

a page by dragging operations from the Data Control Palette.


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Data Action Events

Using built -in events, you can define your ownoperations:

• Defined by:

– Coding an on()method in the data

action

• Invoked by:

– Button with the name “event_” ,

for example, event_Help.

– Button with the name “ event” and value,

for example, name=“ event” value=“ Help” .

– Hyperlink with a parameter event=< operation>,

for example, event=Commit.

Data Action Events (cont inued)

To utilize custom events, create an on( ) method in the data action. Then,

invoke the event by using the same naming convention as the built-in operations.

This is a technique to extend the default behavior without interfering with the standard event life

cycle.


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on Example: Built-in Events

Extending a named buil t-in event

public void onCommit(DataActionContext ctx)

{

HttpSession session = ctx.getHttpServletRequest().getSession();

Boolean loggedOn = (Boolean)session.getAttribute("AUTHFLAG");

if (loggedOn.booleanValue()){

ctx.getEventActionBinding().doIt();

}

}

?event=commit

on Example: Bui lt-in Events

In this example, you can add some logic to a built-in event; for example, allowing the commit

event to take place only if the user is logged in.

Thus, the commit event is triggered through a submit button called “event_commit” or an

argument on the URL (as shown above). This assumes that the UIModel for this data action or

page contains the commit operation.

After the button is pressed, the data action is notified that the commit operation has taken place.The data action then introspects the subclass of data action provided for anonCommi t ( )

method.


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on Example: Custom Events

Calling a custom operation

public void onFoo(DataActionContext ctx)

{

// just direct the flow to the "foo" forward

ctx.setActionForward("foo");

}

event=foo

on Example: Custom Events

In addition to built-in operations that are already registered, you can also code custom events thatare again detected by introspection. In this case, the event f oo simply sets the forward for thedata action or page to the target of the f oo forward.

Note that if there is no operation defined for an event, the data action assumes that the event is in

fact identifying a forward. Thus, event =f oo triggers the flow to follow the f oo forward.


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Summary

In th is lesson, you should have learned how to:• Create data pages mapped to business services

• Create Web applications that uti lize data pages

• Customize data actions and data pages to

enhance the behavior of an application

Summary

This lesson should have taught you how to utilize data pages and data actions to easily

incorporate business services into a Struts-based Web application.


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This practice covers the following topics:• Creating data actions

• Adding methods to data actions


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Practice 12-1

Adding features to data pages.

Start JDeveloper, and open the pr act i ce12 workspace.

1. In this step, you add navigation operations to thecategories page. The buttons allow the

user to navigate forward or backward through sets of category rows.

a. Open the categories data page.

b. In the Data Control pane, open the SalesAppModuleDataControl node, expand the

CategoriesView node, and then the Operations node.

c. Select the Previous Set item, and drag it to the Design Editor following the last

object. If prompted with an Add Form Element Confirmation dialog box, answer Yes.

d. Perform the same steps and add the Next Set operation, and drag it next to the

Previous Set button.

e. You must include the data table inside the form tag that you just added. Go to theSource tab, find the tag, and move it to just above the tag.

f. Next, set the action property of the form tocategories.do.

2. Modify the iterator so that the page does not display all the items at one time. This makes

the pages more user friendly. If the users do not see the category that they are looking for,they can click one of the buttons to see the next set of records, rather than having to scroll

to see all of the categories.a. In the Applications Navigator, click thecategories.jsp node.

b. In the Structure pane, click the UIModel tab, which is the second tab at the top of the

Structure pane.

c. Click CategoriesViewIterator and set the Range Size value to 5 in the Property

Inspector. This restricts the number of categories displayed on a page to 5.

3. Add navigation operations to the products page.

a. Open the products data page. b. Within the CategoriesView node, expand the ProductInformationView node, and

then the Operations node and add Previous Set and Next Set items as you did for thecategories page. Do not forget to move thetag and set the action property topr oduct s. do.

4. Modify the products iterator to display 5 rows just as you did for the categories iterator.

5. Clean up the unnecessary columns from both pages.

a. In the table created for the view, select the first top left cell, right-click, select Table

from the context menu, and select the delete column option.

b. This removes the current_row column from the table.


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6. Create a Master Detail Page navigation for thecategories and products pages.

a. In the page flow, delete the link from categories to products that you created earlier.

b. Open the categories page in the Design Editor, and delete the link and message bean.

c. Select the Operations node for the CategoriesView in the Data Control Palette.

d. Drag the setCurrentRowWithKey categories operation as a Find Row Link to the

CategoryName column. (You can choose any column.)

e. Move the “


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7. Create a data page for ShoppingCartView that you created in an earlier practice.

a. Add the following entries in theAppl i cat i onResour ces file:l i nk. product s=cont i nue shoppi ngl i nk. cat egor i es=choose anot her cat egory

b. Open the Page Flow Diagram, and create a shoppingCart data page with the default

corresponding jsp.

c. Drag the ShoppingCartView data control as a read-only table to the page.d. Select the Struts Html link tag, and drop it at the bottom of the page. Add a Struts

Bean message tag to the link tag, and set the Key value as l i nk. pr oduct s.Specify /products.do as the action value in the Property Inspector..

e. Select the Struts Html link tag and drop it at the bottom of the page. Add a Struts

Bean message tag to the link tag and specify l i nk. cat egor i es as the Key value.Specify /categories.do as the action value in the Property Inspector.

8. shoppingCartView is designed to hold items that the user chooses to buy from the online

store. The user adds the items by clicking a link on the item. The item is then added to

shoppingCartView. The code to accept these items and add them to the cart is in theshoppingCartViewImpl class. Rather than having you type all the code, the code is

already in the class. The instructions for this portion of the practice are to step you through

the code.a. Make the view object capable of using theFi ndByKey method. Setting this

property to true enables you to search the view object by Key. The benefit of using

this technique is that you do not have to iterate through the rows searching for a

match. That function is already written for you.

protected void create()

{

super.create();

setManageRowsByKey(true);

}

// end of create


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c. The f i l l I nCar t I t emDet ai l s( ) method instantiates aProductInformationView and sets its wher e clause to the pr oduct I d of thecurrent car t I t em. It then queries the view object to get the details of the product. Itthen sets the pr oduct Name and l i st Pr i ce of the shoppi ngCar t I t em.


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d. The f i ndCar t I t em( ) method simply takes a pr oduct I d as an argument, andchecks to see whether it exists in the shoppi ngCar t . If it exists, it returns theshoppi ngCar t I t emrow.

e. The car t Tot al ( ) method returns the total of all the items in the cart. To do this, itcreates a r owSet I t er at or of the shoppi ngCar t and iterates through it,summing the ext endedTot al attributes as it does. At the end of theRowSet I t erat or , it returns the total .


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9. After the user has selected the items and added them to the cart, you need to finalize the

order; in other words go through the checkout process. The code creates a single order forthe shoppi ngCar t , and then creates an Or der I t ems row for each row in theshoppi ngCar t This method is in the Sal esAppModul eI mpl class.


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10. Now that all the code is in place to add items to the cart, calculate the total, and even

finalize the order, you need code to get it all started. This method is published in the

application module so that client applications can access it. All the other methods are usedwithin the context of this one method. This method is theaddToCar t method and is alsoin the Sal esAppModul eI mpl class.


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11. Now that the code is in place to complete your application, you can add the elements to add

products to the shoppingCart. The result is a link on the product ID that forwards to aDataAction. The DataAction calls the addToCar t method, which adds the product to the

ShoppingCartView object.

a. Add a DataAction to the page flow, and name it /addToCart.

b. Drag the addToCart method from the SalesAppModule to the DataAction.

c. Change the name of the parameter in the addToCart DataAction topar am. pr odI d. (Use the Structure pane and select paramNames[0].)

d. Add a forward from the products page to theaddToCart DataAction and name it

addToCart.

e. Add a forward from the addToCart DataAction back to the products page. Leave the

name as success.12. Next, add an hr ef to the products page that uses the forward you just defined and passes

the pr oduct I d as an argument. Because this is a common activity, create a code snippet

that makes this easier.

a. Open the code snippet list on the Component Palette. b. Right-click and select Add Component.

c. Name the component “an href with an event and argument”

d. Enter the following code snippet: link words

e. Click OK. You are now ready to use this snippet wherever you need.

f. From the Component Palette, select code snippets. In the Design Editor for the

products page, place your cursor just before theproductId value in the read only

table. Now click the an href item in the Component Palette. This adds your code

snippet to the page.

g. Find the code in the Source Editor and change it for your specific application by

replacing myPage, myEvent, myArg, and myValue. Your code should look like:

h. Add a forward from the products page to the shoppingCart page. Name the forward

viewCart.

13. In the Visual Editor on the products page, add anhr ef that calls the forward to the

shoppingCart. The code should look like the following code (You can use the snippetagain.):View your Cart


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14. Build and test the application starting at thecategories page.

a. Select a category and notice that theproducts page is coordinated with that category.

b. Go back to the categories page and select another category. Observe the same

behavior.

c. Click a product to add it to the shoppingCart.

d. See that the item is added to the cart.

e. Experiment with multiple items by clicking the same item multiple times.f. When you are done, close the browser.


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Adding Validation and Error Handling


Lecture 35 minutes

Practice 30 minutes

Total 65 minutes


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Objectives

After completing this lesson, you should be able to dothe following:

• Validate form input

• Use declarative validation

• Use client-side validation

• Utilize control hints to modify the view

Objectives

Business logic and rules should be enforced in the business tier of an application. However, it is

possible and sometimes useful to validate data at the client level (thus saving the user a round

trip to the server). This provides for an effective and robust user interface. This lesson shows you

how to incorporate client-side validation into the view of a Struts-controlled application.

Additionally, enhancing the view by using control hints is also covered in this lesson.


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Overview of Validation

Method Validators,

Control Hints

ADF

BusinessComponentsStrutsForm Bean Struts Action

Form Bean validate()

method, Struts Validator

JSP

JavaScript New Validation Methods

Overview of Validation

Validation can be performed at many levels of an application. You have already seen how to

create validation methods in ADF Business Components by using method validators. However,

there are several ways to incorporate validation in Struts: utilizing the form beanval i dat e( )

method, or by creating custom validation classes and calling their methods from theexecut e( ) method of a Struts action. There is also a plug-in available in Struts, which

incorporates common validation rules. Additionally, simple validation can be performed at the

client level by creating a JavaScript file, which is referenced in the JavaServer Pages (JSP).


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Need for Validation

In Web applications, the user usually does not receivetraining on how to complete fields correctly. Thus, an

application must provide feedback to the user for

these types of actions:

• Entering required values

• Specifying values within a specif ied range

• Comparing values

– For example, Password1 must match Password2.

Need for Validation

Client-side validation enables immediate response to a user interacting within an HTML form.

For example, the response can display an alert when a business rule is violated or correct data if

an entry does not have the desired format. Client-side validation is not meant to replace server-

side enforcement of business and format rules. It should be thought of as a convenience for the

end user to avoid waiting for a server response simply to determine whether the submitted data is

correct.


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Client-Side Validation

To perform validation by using Struts, you must:1. Create a form bean class

2. Overwrite the form bean validate() method,

passing an error to the action

3. Create the error message in ApplicationResources.properties

4. Add the input attribute for the form to the action to

indicate where the error message should appear

Client-Side Validation

Validation can be incorporated by using the form bean class of a Struts action. The form beancontains a val i dat e( ) method, where you can define the validation logic. The next step is tocreate a message for the error in the Appl i cat i onResour ces. pr oper t i es file.


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Form Bean Validation Method

The form bean contains a validate() method for

validating form f ields. Overwrite this method to

perform custom validation:

public ActionErrors validate(ActionMapping

mapping, HttpServletRequest request)

{

ActionErrors errors = new ActionErrors();

if ((username == null) ||

(username.trim().equals("")))

{

errors.add("username", new

ActionError("error.username.required"));

}

return errors;

}

Form Bean Validation Method

After you have created a form bean class, overwrite theval i date( ) method to perform

validation on form fields. In this example, if the form field “username” is a null value or an

empty string, the er r or . user name. r equi r ed error is passed to the action. The next step isto create a message for this error in the Appl i cat i onResour ces. pr oper t i es file.


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Creating the Error Message

• To display the error message, specify themessage in ApplicationResources.properties:

• Define where the error message is to be displayedby using the input attribute:

error.username.required=The Username Value must be

Supplied

Creating the Error Message

To create the error message, add it to the Appl i cat i onResour ces. pr oper t i es file. Inthe example above, this corresponds to Act i onEr r or created in the form bean’s val i date( )method. Note that the val i dat e attribute of the action should be set to “true,” which is the

default.


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Printing Errors in the JSP

Ensure that the JSP contains an tag:

Note that you can specify the property attribute of the

tag to print only the correspondingerror:

…

…

Printing Errors in the JSP

The tag must be included in the JSP to display the error. This tag is available

in the Struts HTML category of the Component Palette. There are two ways to display the error,

as shown below.

Specific

(property attribute set)

Generic


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Validating Actions

A second type of validation is to overwrite the executemethod in the action class. This type of validation is

useful when:

• You have previously created classes that check

the validity of a given value

• You do not want the form values to be reset after

validation

• The validation logic is complex

Validating Actions

Instead of validating form input by using theval i dat e( ) method, you can also validatevalues by using the execut e( ) method of the action. This is especially useful if you already

have JavaBeans or other classes that evaluate user input.


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Creating a Validation Class

The first step in validating user input is to create amethod for validation. This can be done in a simple

class file, as shown:

package view;

public class LoginValidation

{

boolean checkUsernamePassword(String un, String pw)

{

if ( un.equals("scott") && pw.equals("tiger") )

return true;

else

return false;

}

}

Creating a Validation Class

To validate using the action, you must first create a method for validation. This should be done

outside the action and action form bean classes, in a new file. The example above contains one

method, checkUser namePasswor d( ) , which returns t rue if the username is scot t andthe password is t i ger . This is, of course, a simple example. The code for validating the

username and password in a more complex application can validate based on database values.


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The execute() Method

To validate user input in the action class, overwri te theexecute() method, calling your validation method:

public ActionForward execute…

{

LogonActionForm logonForm = (LogonActionForm) form;

String un = logonForm.getUsername();

String pw = logonForm.getPassword();

LoginValidation loginvalidation = new

LoginValidation();

if ( loginvalidation.checkUsernamePassword(un,pw))

{


} else return mapping.findForward("failure"); }

The execute() Method

Call the validation method that you have created in theexecut e( ) method of the action class.

To access the values of the form fields, create an instance of the form bean and utilize theget() methods in the form bean. This example uses the f i ndFor war d( ) method to direct

the user to the appropriate page. You can then use the Struts logic tags to determine whether the

user entered incorrect data, and display a helpful message if the user is attempting a login for the

second time.


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Struts Validator

Declaratively validate form fields by using the StrutsValidator. The validator plug-in:

• Is XML based

– validator-rules.xml (Validation rules)

– validations.xml (Usages)

• Defines rules for each f ield in a form bean

• Can provide client validation using JavaScript

• Is extensible

Struts Validator

Validator is driven by two XML files, val i dat or - r ul es. xml and val i dat i ons. xml .val i dat or - r ul es. xml describes all the validation rules that can be used, such asr equi r ed, maxLengt h, i nt eger , and so on.

Each rule is defined in val i dat i ons. xml , which applies rules to the various fields in a form

bean. If validation fails, the user is redirected to the input page with the relevant error messagesfrom the validator. Note that val i dat or - r ul es. xml is extensible. You can add custom

validation rules by utilizing the appropriate classes to implement them.

Besides for server-side validation, val i dat or - r ul es. xml can also have a JavaScriptcomponent for client-side validation.


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Setting Up the Struts Validator

1. Specify the validator class in the tag of

struts-config.xml.

2. Add validation-rules.xml to your project.

3. Modify the form bean class to subclass ValidatorForm or DynaValidatorForm .

4. Create a usage file to specify form field rules.

5. Add error messages to

ApplicationResources.properties.

Setting Up the Struts Validator

Perform the steps above to set up your application workspace to utilize the Struts Validator. The

next few slides explain these steps in detail.


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Util izing the Struts Validator

Add ValidatorPlugIn to the tag and

specify the path for validator-rules.xml and

validation.xml:

Utilizing the Struts Validator

The necessary files for utilizing the Struts Validator are contained

Documents

Oracle JDeveloper 10g Build Applications with ADF Instructor Guide - Volume 2.pdf