JSP tag libraries / how to develop powerful custom JSP tags

This is a review I did for AustonJUG group. Since it is a long review (more than 1000 words), I only post the overview here....Working with other server side Java components, such as JavaBeans, EJBs and JDBC, properly designed custom tag libraries allow developers to encapsulate and reuse code. Custom tags create a tag-based content authoring environment and allow web authors to write highly dynamic web applications in HTML style without learning the Java programming language. So, architects, developers and content authors can all benefit from studying JSP custom tags. brief contents......Page 5 contents......Page 7 preface......Page 17 acknowledgments......Page 19 about this book......Page 21 author online......Page 26 about the cover illustration......Page 27 The big picture......Page 31 1.1 The JSP custom tags solution......Page 32 1.2.1 HTTP protocol......Page 33 1.3 Dynamic web servers......Page 37 1.3.1 Common Gateway Interface......Page 38 1.3.2 Web server APIs......Page 40 1.3.3 Server pages techniques......Page 41 1.3.4 Separating business and presentation logic......Page 43 1.4 Tag-based programming......Page 45 1.4.1 Benefits of a tag-based approach......Page 46 1.5 WAP, voice, and other alternative web clients......Page 47 1.6 Summary......Page 50 Web development with Java......Page 51 2.1 Java and dynamic web content......Page 52 2.2.1 The servlet API and programming model......Page 53 2.2.2 Servlets and non-Java web servers......Page 58 2.2.3 Servlet shortcomings......Page 59 2.3 Introduction to JavaServer Pages......Page 60 2.3.2 A JSP example......Page 61 2.3.3 Scriptlets......Page 62 2.3.4 Implicit variables......Page 65 2.3.5 Directives......Page 66 2.3.6 Tags......Page 68 2.3.7 Tags for JavaBean manipulation......Page 69 2.3.8 Executing a JSP page......Page 71 2.4.1 Model-1......Page 76 2.4.2 Model-2......Page 77 2.5 Servlets, JSP, and application configuration......Page 80 2.5.1 The WAR file and its structure......Page 81 2.5.2 The application deployment descriptor......Page 83 2.6 Summary......Page 85 Developing your first tags......Page 86 3.1.1 Anatomy of a tag......Page 87 3.1.2 Using a tag in JSP......Page 88 3.1.3 The tag library descriptor......Page 89 3.2 Why tags?......Page 90 3.3 Setting up a development environment......Page 91 3.3.2 Installing Tomcat......Page 92 3.3.3 Testing your Tomcat installation......Page 93 3.4 Hello World example......Page 94 3.4.1 Compiling the tag......Page 95 3.4.2 Creating a tag library descriptor (TLD)......Page 96 3.4.3 Testing HelloWorldTag......Page 97 3.4.5 A tag with attributes......Page 100 3.4.6 Packaging tags for shipment......Page 103 3.5 A tag with a body......Page 104 3.5.1 LowerCaseTag handler......Page 105 3.6 Summary......Page 107 Custom JSP tag API and life cycle......Page 108 4.1 Requirements of custom tags......Page 109 4.2 Overview of the tag API......Page 111 4.2.1 Tag interface......Page 115 4.2.2 Tag life cycle......Page 118 4.3.1 BodyTag interface......Page 122 4.4 Tag API classes......Page 125 4.4.2 PageContext class......Page 127 4.4.3 BodyContent class......Page 128 4.5.1 TryCatchFinally interface......Page 129 4.5.3 EVAL_BODY_BUFFERED , EVAL_BODY_AGAIN return codes......Page 130 4.5.4 Updated Tag life cycle......Page 131 4.6 Summary......Page 134 Integrating custom tags with the JSP runtime......Page 135 5.1 Tag library descriptor in a nutshell......Page 136 5.1.1 The role of the TLD......Page 138 5.2 Referencing a tag library from a JSP......Page 140 5.2.1 The Taglib’s uri attribute......Page 141 5.3.1 Send tag example......Page 145 5.3.2 Translating the JSP into a servlet......Page 149 5.4 Summary......Page 154 Tag development techniques......Page 157 6.1.1 The techniques you'll use most......Page 158 6.2 Writing content back to the user......Page 160 6.2.1 Adding data to the output......Page 161 6.2.3 Flushing the JspWriter’s internal buffer......Page 165 6.3 Setting tag attributes......Page 167 6.3.1 Specifying tag attributes in the TLD......Page 168 6.3.2 Providing validity checks at translation time......Page 170 6.3.3 Using the JavaBeans coding conventions......Page 173 6.4 Logging and messaging......Page 174 6.4.2 Handling and throwing exceptions......Page 175 6.4.3 Improving logging......Page 176 6.5 Using the Servlet API......Page 178 6.5.1 Accessing the implicit JSP objects......Page 179 6.5.2 Accessing the JSP attributes......Page 188 6.6 Configuring tags and bundling resources......Page 197 6.6.1 Configuring a web application......Page 198 6.7 Working with the tag’s body......Page 204 6.7.1 Tag body evaluation......Page 205 6.7.2 Referencing your tag's body......Page 208 6.7.3 A BodyTag example–logging messages......Page 212 6.8 Tag cooperation through nesting......Page 216 6.9 Cleaning up......Page 217 6.9.2 Exceptions and cleanup......Page 218 6.9.3 Improving our base classes to handle cleanup......Page 220 6.10 Summary......Page 222 Building a tag library for sending email......Page 223 7.1.1 The Simple Mail Transfer Protocol......Page 224 7.1.2 Java-based email......Page 225 7.2.1 SimpleJavaMailTag example......Page 228 7.3.2 Using an existing mail session......Page 234 7.3.4 An enhanced SimpleJavaMailTag: JavaMailTag......Page 235 7.3.5 The JavaMailTag in action......Page 240 7.4 Collecting attributes from the tag’s body......Page 243 7.4.2 Extending the email tag......Page 245 7.4.3 Creating tags for subject and message......Page 246 7.5 Adding assertions and input validation......Page 251 7.5.1 Performing validation using custom tags......Page 252 7.5.2 Creating a tag for the send mail tag library......Page 253 7.6 Summary......Page 261 Using JavaBeans with tags......Page 263 8.1 Java reflection......Page 264 8.1.1 What is reflection?......Page 265 8.1.2 The reflection API......Page 266 8.2.2 JavaBeans properties......Page 272 8.2.4 Properties and introspection......Page 275 8.3 The Show tag......Page 279 8.3.1 Components of the tag......Page 280 8.4.1 Informing the runtime of exported scripting variables......Page 292 8.4.2 The ExportTag......Page 298 8.5 Summary......Page 303 Posing conditions with tags......Page 307 9.1 Evaluating conditions in JSPs......Page 308 9.2 IfTag—A simple condition tag......Page 309 9.2.1 Implementing IfTag......Page 310 9.2.2 The problem with IfTag......Page 311 9.3 The advanced condition tag family......Page 313 9.3.1 WithTag......Page 315 9.3.2 TestTag......Page 318 9.3.3 TLD for the advanced condition tags......Page 324 9.3.4 Our tag library in action......Page 325 9.4 Improving our advanced condition tags......Page 327 9.4.2 Supporting complex conditions with JavaBeans......Page 328 9.5 Summary......Page 329 Iterating With Tags......Page 330 10.1 Iterating with tags 101......Page 333 10.1.1 Iteration example: SimpleForeachTag......Page 334 10.2.1 A generic iteration interface......Page 339 10.2.2 IterationTagSupport......Page 340 10.3.2 Wrapping iterators......Page 345 10.3.3 Implementing IterateTag......Page 347 10.4.1 Printing the shopping cart with scriptlets......Page 351 10.4.2 Printing the shopping cart with IterateTag......Page 353 10.5 Making it easier on the JSP author......Page 354 10.5.2 The design......Page 356 10.5.3 FieldGetter and ReflectionFieldGetter......Page 357 10.5.4 Integrating FieldGetter with IterationTagSupport......Page 358 10.5.5 Updating IterateTag to perform field substitution......Page 362 10.5.6 Field substitution in action......Page 363 10.6.1 IterationTag......Page 364 10.7 Summary......Page 366 Database access with tags......Page 368 11.1 Choosing how to present database information......Page 369 11.2 Designing our database presentation tag library......Page 370 11.2.2 Additional design considerations......Page 371 11.3 IterateResultSetTag......Page 373 11.3.1 ResultSetIterationSupport class......Page 374 11.3.2 JDBCFieldGetter class......Page 375 11.3.3 IterateResultSetTag in action......Page 376 11.4 Full JDBC connectivity through tags......Page 377 11.4.1 Improving our one-tag approach......Page 378 11.5.1 Requirements......Page 380 11.5.2 Choosing our tags......Page 382 11.6 Implementing the library......Page 385 11.6.1 DBConnectionTag......Page 386 11.6.2 SQLQueryTag......Page 393 11.6.3 EnumRsTag......Page 398 11.6.4 Using our library for the first time......Page 401 11.6.5 ViewRsTag......Page 403 11.7.1 The controller servlet......Page 408 11.7.2 The JSP......Page 410 11.8 Summary......Page 411 Custom tags and J2EE......Page 413 12.1 What is J2EE?......Page 414 12.1.1 J2EE server components and client access......Page 416 12.1.3 Why custom tags and J2EE are a good fit......Page 417 12.2.1 EJBs—What are they?......Page 418 12.2.2 Types of EJB components......Page 420 12.2.3 EJBs and their functions......Page 423 12.2.4 Example: catalogue entry EJB......Page 425 12.3 Using and configuring J2EE services......Page 434 12.3.1 Getting services......Page 435 12.3.2 Tag and servlet API integration......Page 436 12.3.3 Setting environment entries......Page 437 12.3.4 Setting EJB reference entries......Page 438 12.3.5 Setting resource factory reference entries......Page 439 12.3.6 Wrap it up......Page 440 12.4.1 DataSource......Page 441 12.4.2 Updating database tags to use J2EE conventions......Page 442 12.5.1 Defining a mail service......Page 449 12.5.2 Referencing the mail service......Page 450 12.5.3 J2EE send tag......Page 452 12.6.1 Writing custom tags for EJB access......Page 457 12.6.2 Retrieving the EJB home interface......Page 458 12.6.3 Using the EJB home interface......Page 462 12.7 Summary......Page 470 JDBC-driven WebStore......Page 473 13.1.1 Custom tags used......Page 474 13.2 Overview......Page 475 13.3 Requirements......Page 476 13.4.1 Model......Page 480 13.4.2 View......Page 484 13.5 Implementation......Page 489 13.5.1 Tags......Page 490 13.5.2 Views......Page 502 13.6 Summary......Page 554 EJB-driven WAPStore......Page 555 14.1.1 Custom tags used......Page 556 14.2 Overview......Page 557 14.3.1 Normal flow of events......Page 558 14.3.2 Model......Page 559 14.3.3 View......Page 560 14.3.4 Welcome view......Page 563 14.3.5 Controller......Page 589 14.4 Summary......Page 591 JSP tag libraries— tips and tricks......Page 595 15.1.1 Tags and nonprogrammers......Page 596 15.1.2 Reusing tags......Page 597 15.1.4 Tags and application performance......Page 598 15.2.1 Tag development dos......Page 599 15.2.2 Tag development don’ts......Page 604 15.3.2 Testing tags on more than one JSP container......Page 606 15.4.1 Opening library internals......Page 607 15.4.2 Generalizing your tags......Page 608 15.4.3 Integration and the surrounding environment......Page 611 15.5.1 The tag life cycle......Page 612 15.5.3 Freeing allocated resources......Page 613 15.6 Summary......Page 614 What is XML?......Page 617 A.2 XML syntax......Page 618 A.2.1 DTDs......Page 620 A.3 XML pitfalls......Page 621 A.4 Why XML?......Page 622 A.6 Additional reading......Page 623 The Tag Library Descriptor......Page 625 B.1.1 The taglib element......Page 626 B.1.2 The tag element......Page 627 B.1.3 Element Recap......Page 629 B.2 A sample TLD......Page 630 B.3.1 New taglib elements......Page 632 B.3.2 New tag elements......Page 633 B.4 Summary......Page 635 Using the code examples......Page 636 C.1.2 Using the example tags......Page 637 C.1.3 Compiling the example tags......Page 638 C.2.1 The WebStore application......Page 639 C.2.2 The WAPStore application......Page 641 references......Page 643 index......Page 645 "If you are a JavaServer Pages programmer looking to give your page developers a powerful yet simple syntax for building pages, you will want them to use JSP tags. This book teaches you how to develop custom tag libraries that can separate presentation from implementation, expose functionality in robust and reusable packages, provide easy access to J2EE services, and ultimately avoid the use of scriptlets (with which a page developer can inadvertently cause errors or even shut down your entire system)." "JSP Tag Libraries also shows how tag libraries can clarify the flow of events in a page, making it easy to follow what's happening -- and to find out what's not (i.e., to debug). It covers two full-scale use cases showing the effectiveness of tags in the context of ecommerce and of WAP applications." "Because tags help systematize reuse and let non programmers access powerful system features, tag libraries will have a huge impact on the way people develop JSPs. Book jacket."--BOOK JACKET