WebWork in Action

Description:

The WebWork framework implements a simple command/ business-logic and MVC design. It provides out-of-the-box functionality developers need to build well-designed applications that are modular and reusable. Written by its two primary developers, WebWork in Action is the first book to focus entirely on WebWork. Like a true "In Action" book, it is both a tutorial on WebWork and a sourcebook for its use in demanding, real-world applications.

Starting with "Hello World" the Webwork way, the book immerses the reader in practical, how-to material. You will soon know how to configure WebWork and gradually and incrementally master the robust and powerful uses of the framework. WebWork in Action uses the same basic, continuing example used in Manning's Hibernate in Action to show how to integrate WebWork with the popular Hibernate persistence framework.

What's Inside

• Handling data and displaying content with Expression Language and Tag Libraries
• Inversion of Control and WebWork actions
• VelocityType conversion and data validation
• Internationalization and component-oriented design
• Integration of web applications into the Hibernate persistence framework
• Webwork best practices and architecture

 

foreword xv
preface xvii
acknowledgments xix
about this book xxi
a look at the future xxvi
about the title xxvii
about the cover illustration xxviii

Part 1 Introduction to WebWork 1

1 An overview of WebWork 3

Why MVC is important 5

Classic MVC becomes outdated 6, Classic MVC gets an update: the Front Controller 7, MVC evolves: the Page Controller 7

Understanding frameworks and containers 9

What is a framework? 9, What a container can do 11

WebWork: past, present, and future 13

The history of WebWork 13, Understanding the XWork core 13

Future directions 15

The CaveatEmptor application 15

How CaveatEmptor is organized 16

Summary 17

2 HelloWorld, the WebWork way 19

Downloading WebWork 20

Preparing the skeleton 20

Creating the web.xml deployment file 21, Creating the xwork.xml configuration file 23, Creating the webwork.properties configuration file 23, Tips for developing WebWork apps 24

Your first action 24

Saying hello, the WebWork way 25, Displaying output to the web browser 26, Configuring your new action 27

Dealing with inputs 28

Advanced control flow 31

Letting WebWork do the work 33

Taking advantage of ActionSupport 34, Intermediate modifications to the JSP 35, Exploring the UI tag library 36

Summary 37

3 Setting up WebWork 38

Configuring actions, results, and interceptors 39

Overview of terminology 39, Actions 40

Results 46, Interceptors 48

Advanced configuration 52

The xwork.xml DTD 52, Namespaces and packages 53

Componentization using the include tag 57

Other configuration files 66

Web-app configuration: web.xml 66

Feature configuration: webwork.properties 67

Setting up your web app 70

General layout 70, Required libraries 71, Optional libraries 72

Summary 72

Part 2 Core concepts 75

4 Implementing WebWork actions 77

The Action interface 78

Result codes 78, Handling exceptions 79

Using the ActionSupport base class 80

Understanding basic validation 80

Validating an action: Validateable 81

Displaying error messages: ValidationAware 82

Using localized message texts 86

Retrieving the user疄 locale: LocaleProvider 86

Displaying the localized text: TextProvider 86

Providing messages for other languages 89

Advanced inputs 90

Intermediary objects 90, Using domain objects directly 91

Working with ModelDriven actions 95

Implementing ModelDriven actions 96

Considerations when using ModelDriven 100

Accessing data through the ActionContext 102

CaveatEmptor: accessing the session 102

Example: accessing the request and response 105

Handling file uploads 107

Accessing uploaded files through the request wrapper 107

Automating file uploads 109, Configuration settings 110

Summary 111

5 Adding functionality with interceptors 112

How interceptors are called 113

Using the prepackaged interceptors 114

Utility interceptors 117, Setting parameters 119

Defining workflow 123

Using prepackaged interceptor stacks 126

Building your own interceptors 128

Using the AroundInterceptor as a base 129, Looking at an example custom interceptor 130, Getting callbacks before the result is executed with the PreResultListener 133, Looking out for interceptor interactions 134

Interceptors vs. servlet filters 135

Summary 136

6 Inversion of Control 137

Examining the pattern 138

Common patterns for active resource management 138, Inverting resource management 142, How IoC helps with testing 145

IoC essentials 146

WebWork疄 IoC history 146, Dependencies 148

Scope and lifecycle 149

Using WebWork疄 IoC framework 151

Configuration 151, Creating a new component 154, Using IoC on any object 158, Dealing with complex dependencies 159

An example from CaveatEmptor 162

The HibernateSessionFactory component 163, The Persistence Manager component 165, Configuring the components 168

Using the new components 169

Alternatives 170

Alternative IoC containers 170, Non-IoC alternatives 172

Summary 173

Part 3 Displaying content 175

7 Using results 177

Life after the action 178

A simple result 178, Configuring a result 180

Common results 182

Dispatching to a page 182, Redirecting to a page 188

Chaining to another action 192

Other results 197

Streaming Velocity templates directly to the output 197

FreeMarker: an alternative to Velocity 202

Generating reports with JasperReports 203

Summary 207

8 Getting data with the expression language 209

What is an expression language? 210

Why an expression language? 210, Why OGNL? 211

Other expression languages 212, Key OGNL concepts 213

Basic expression language features 213

Accessing bean properties 214, Literals and operators 215

Calling methods 217, Setting values and expression lists 218

Accessing static methods and fields 218, Accessing the OGNL context and the ActionContext 218

Working with collections 220

Working with lists and arrays 220, Working with maps 221

Filtering and projecting collections 222, The multiple uses of ??223

Advanced expression language features 224

Linking the value stack to the expression language 224

Data type conversion 226, Handling null property access 227

Creating lambda expressions on the fly 228

Summary 228

9 Tag libraries 230

Getting started 231

An overview of WebWork tags 232

The WebWork tag syntax 233

Data tags 235

The property tag 235, The set tag 236, The push tag 237

The bean tag 238, The action tag 240

Control tags 242

The iterator tag 242, The if and else tags 245

Miscellaneous tags 246

The include tag 246, The URL tag 247, The i18n and text tags 250, The param tag 252

Summary 253

10 Velocity 254

Introduction to Velocity 255

What is Velocity? 255, Getting ready to use Velocity 257

Basic syntax and operations 259

Property access 259, Method calls 261, Control statements: if/else and loops 261, Assigning variables 265

Advanced techniques 265

The VelocityContext 265, WebWork-supplied objects in the context 266, Customizing the Velocity context 267

Using JSP tags in Velocity 268

Loading Velocity templates 269

Summary 269

11 UI components 271

Why bother with UI tags? 272

Eliminating the pain 272, More than just form elements 280

UI tag overview 283

Templates 283, Themes 285, Tag attributes 291

UI tag reference 291

Common attributes 291, Simple tags 294

Collection-based tags 299, Advanced tags 305

Summary 309

Part 4 Advanced topics 311

12 Type conversion 313

Why type conversion? 314

The Servlet specification 314, An action without type conversion 315, A view without type conversion 317

What WebWork疄 type conversion gives you 319

Configuration 320

Role of a type converter 321, Global type converters 322

Class-level type converters 322

Simple type conversion 323

Basic type conversion 323, Built-in type conversion 325

Handling null property access 326

Advanced topics 326

Handling null Collection access 326, Handling conversion errors 329, An example that puts it all together 330

Summary 331

13 Validating form data 333

Manually validating data 336

Validating in the execute() method 336

Implementing the Validateable interface 337

Using the Validation Framework 340

Building your first *-validation.xml file 340, Registering validators 341, Applying the validation interceptor 345, Pulling it all together 346, Looking at some validation XML examples 348

Exploring the advanced features of the Validation Framework 350

Implementing a custom validator 351, Validating with different contexts 353, Short-circuiting validation 354

The ExpressionValidator 355, Reusing validations with the visitor field validator 356

Summary 359

14 Internationalization 360

Exploring a quick internationalization example 361

Sources for messages 362

Understanding the ResourceBundle search order 364. Adding default resource bundles 366, The tag 366

Using internationalized messages 368

Parameterizing localized texts 368, Using getText() in taglib attributes 369, Formatting dates and numbers 370, Using localized messages in validations 370, Using internationalized texts for type conversion messages 371

Tips and tricks 373

Programmatically setting the locale 373, Implementing ResourceBundles as classes 375, Using the tag to pass dynamically generated text to message texts 378, Setting the encoding: here, there, and everywhere 381, A note on Java PropertyResourceBundles 382, A final note 382

Summary 383

15 Best practices 384

Setting up your environment 385

Setting up your IDE 386, Reloading resources 388

Unit-testing your actions 389

Using mock objects 389, The advantage of IoC for testing 391

Handling statics and ThreadLocals 391

Putting the pieces together: integration testing 393

Testing your configuration 393

Seeing the configuration with the config browser 396

Testing validations 398

Testing programmatic validations 398

Testing validation.xml files 398

Advanced UI tag usage 402

Overriding existing templates 403, Writing custom templates 406

Writing custom themes 407

Using form tokens to prevent duplicate form submissions 409

Using the tag 410, Applying the TokenInterceptor 412, Transparently re-rendering pages with the TokenSessionStoreInterceptor 413

Displaying wait pages automatically 413

A Single action for CRUD operations 417

Creating new categories with newCategory 418, Reading and updating with viewCategory and editCategory 419, Saving categories with saveCategory 420, Setting the parentCategory 422

Summary 423
 
WebWork architecture 424
index 439