What's New In Struts 1.1 Session TU07 – 11/19/2002 – 13:30-14:30 Craig R. McClanahan Senior Staff Engineer Sun Microsyst

1. What's New In Struts 1.1 Session TU07 – 11/19/2002 – 13:30-14:30 Craig R. McClanahan Senior Staff Engineer Sun Microsystems, Inc.

2. Session Outline • Welcome • New Features In Struts 1.1 • What Does The Future Hold? • Q&A

3. Welcome

4. Welcome • I'm assuming you are familiar with Struts 1.0 • For an introduction, please attend session WE06 tomorrow at 1:30pm: “Building Web Applications With Struts” • Two BOFs tonight will also be of interest: • 8pm – Struts After 1.1 – Where Do We Go From Here? • 9pm – JSP New And Improved – The JSP 2.0 Specification

5. Welcome • Struts 1.0: • Original Release: June 2001 • Version 1.0.2: February 2002 • Struts 1.1: • Version 1.1-b1: March 2002 • Version 1.1-b2: September 2002 • Version 1.1 Final: “Real Soon Now”

6. Welcome • The “Struts community” is growing • Users • STRUTS-USER has 2399 subscribers • Second only to TOMCAT-USER (2454) • Downloads: • October 2002: 29,199 • Tomcat runs 80k-100k per month • Articles and Books: • Five recently published • http://jakarta.apache.org/struts/resources/ • So What's New In Struts 1.1?

7. New Features In Struts 1.1

8. New Features In Struts 1.1 • Jakarta Commons Libraries • DynaActionForm • Declarative Exception Handling • PlugIn API • STRUTS-NESTED Tag Library • STRUTS-EL Tag Library (Contrib) • Application Module Support

9. Jakarta Commons Libraries • Small, tightly focused, class libraries • Several originated in Struts 1.0 • Included Libraries: • Beanutils – JavaBean manipulation • Collections – Extensions to JDK collections • Dbcp – JDBC connection pools • Digester – XML file parsing • Fileupload – HTML file upload support • Lang – Extensions to JDK class libraries • Logging – Wrapper around log implementations • Pool – Object pools (used by DBCP) • Validator – Field validation framework

10. COMMONS-BEANUTILS • Generic JavaBean property manipulation • Originally from Struts 1.0 • New features: • Pluggable type converters • Mapped properties: • Contact.phone(Work) • DynaBean interface and basic implementations • Dynamically defined sets of properties • BeanUtils and PropertyUtils transparently support DynaBeans and standard JavaBeans • Struts implementation: DynaActionForm

11. COMMONS-BEANUTILS public interface DynaBean { public Object get(String name); public Object get(String name, int index); public Object get(String name, String key); public void set(String name, Object value); public void set(String name, int index, Object value); public void set(String name, String key, Object value); }

12. COMMONS-DBCP • Provides javax.sql.DataSource (connection pool) implementation • Connection timeouts • Both getConnection() methods supported • Idle connections can be released • Validation query tests connection before return • For backwards compatibility, org.apache.struts.util.GenericDataSource is a wrapper around DBCP. • FYI: Tomcat 4.1 also uses this implementation.

13. COMMONS-FILEUPLOAD • Original code from Turbine • Supports file uploads as defined by RFC 1867. • For backwards compatibility, org.apache.struts.upload.MultipartUploadHandler implementations wrap this.

14. COMMONS-LOGGING • Wrapper around any logging API • Intelligent discovery mechanism • Did I ask for a specific factory? Use it. • Is Log4J available? Use it. • Is JDK 1.4 logging available? Use it. • Fallback to default logger • Simple System.err logging implementation is available • Relies on underlying logging implementation for configuration

15. COMMONS-VALIDATOR • Original code from Struts • General framework for validating input data against defined rules • Struts Integration: • ValidatorActionForm and DynaValidatorActionForm • Configure Validator via Plug-In Architecture

16. DynaActionForm • A common user complaint: writing ActionForm beans is a pain • Now, in many cases you will not have to! • Only necessary to provide non-default reset() and/or validate() methods • Configure the properties and their types in your struts-config.xml file • Transparently supported by all of the existing Struts machinery

17. DynaActionForm <form-bean name="logonForm" type="org.apache.struts.action.DynaActionForm"> <form-property name="username" type="java.lang.String"/> <form-property name="password" type="java.lang.String"/> </form-bean>

18. Declarative Exception Handling • Previously, an Action had to deal with all business logic exceptions itself • Now, you can choose to delegate exception handling to other application resources • Global and per-Action mapping declared in struts-config.xml (like forwards): • From a particular Exception class or superclass • To an application-relative path • Requires a small change to your Action to leverage this feature ...

19. Declarative Exception Handling public ActionForward execute (ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception { ... throw new PasswordExpiredException(...); ... }

20. Declarative Exception Handling <action path="/logon" ...> ... <exception key="expired.password" type="o.a.s.w.e.ExpiredPasswordException" path="/changePassword.jsp"/> ... </action>

21. PlugIn API • Before, you had to subclass ActionServlet (or define a separate servlet) to initialize application resources at startup time • Now, you can declare a PlugIn that receives notification of application startup and shutdown public interface PlugIn { public void destroy(); public void init(ActionServlet servlet, ApplicationConfig config) throws ServletException; }

22. STRUTS-NESTED Tag Library • If you ever programmed in Pascal, you might remember the "with" statement ... • Nested tags allow you to establish a default bean for nested property references • 1:1 correspondence, and identical functionality, of other Struts tags • Except the "name" property gets set for you automatically ...

23. STRUTS-NESTED Tag Library • Before using the nested tags: <bean:write property="address.city"/> <bean:write property="address.state"/> <bean:write property="address.zip"/> • After using the nested tags: <nested:nest property="address"> <nested:write property="city"/> <nested:write property="state"/> <nested:write property="zip"/> </nested:nest>

24. STRUTS-EL Tag Library • Inspired by the expression language that is available in the JSP Standard Tag Library. • ${customer.address} • ${customer.address[0].city} • ${cusotmer.addressMap['Postal']} • Includes “EL-ized” versions of all Struts tags that do not have natural replacements in the JSTL tag library. • Nearly every tag attribute supports EL. • Shipped in the “contrib” subdirectory, not currently integrated into Struts core.

25. STRUTS-EL Tag Library • Requires a Servlet 2.3 / JSP 1.2 container • Such as Tomcat 4.x or later • Requires the “standard” taglib from the Jakarta Taglibs project • http://jakarta.apache.org/taglibs/doc/standard-doc/intro.html

26. Application Module Support • Very popular user request for large scale applications • Design goals: • Support multiple independent struts-config.xml files in the same webapp • Modules are identified by an "module prefix" that follows the context path • Existing Struts-based applications should be able to be installed individually, or as a module, with no changes to the pages, Actions, form beans, or other code

27. Application Module Support • Implications of the design goals: • "Default" module with a zero-length prefix (like the ROOT context in Tomcat) • "Context-relative" paths must now be treated as "module-relative" • ActionServlet initialization parameters migrate to the struts-config.xml file • Controller must identify the relevant module, and make its resources available (as request attributes)

28. Application Module Support • The goals appear to have been achieved: • Please download the latest nightly build and help us by testing your apps as modules • Current restrictions: • All requests must flow through the controller – no direct hyperlinks to JSP pages with Struts tags • Can be lifted by implementing the controller as a Filter in Servlet 2.3 • Works only for extension-mapped paths to the controller servlet (*.do)

29. What Does The Future Hold?

30. What Does The Future Hold? • In the mean time, the Java world around web applications is changing ... • Servlet 2.4 (JSR-154) • JSP 2.0 (JSR-152) • JSP Standard Tag Library 1.0 (JSR-52) • JavaServer Faces (JSR-127) • And new things are becoming popular ... • Web services • Portals

31. Servlet 2.4 • Some nice additions • Request lifecycle events • Request dispatcher events • But not likely to affect Struts in the near term • However, it may soon be time to migrate Struts to be based on Servlet 2.3 (and JSP 1.2) or later • Filters and lifecycle listeners • Request and response wrappers • JSP Standard Tag Library ...

32. JavaServer Pages (JSP) 2.0 • Expression Language • Available now in JSP Standard Tag Library • In JSP 2.0, can use in all tag attributes, as well as in template text • We can help the transition by supporting this in Struts tags • JSP Fragments • Create parameterized "custom actions"

33. JSP Standard Tag Library (JSTL) 1.0 • Version 1.0 released, June 2002 • RI based on code from Jakarta • http://jakarta.apache.org/taglibs/ • Core library has familiar functionality • URL, XML, and I18N tags also very useful • Expression language allows for much simpler tags • JSP containers can optimize performance • Struts users should definitely planon utilizing these tag libraries

34. JavaServer Faces • A frequently asked question this year: • What's the deal with Struts and JavaServer Faces? • The short version of the answer: • JavaServer Faces will be a useful mechanism to build the UI for Struts-based web applications • For the longer version of the answer, let's go back into history for a moment ...

35. JavaServer Faces • Where did Struts come from? • Two years of discussion about MVC and Model 1 versus Model 2 • My experience building a large scale web application that was fully internationalized • The key feature – separation of concerns • The key technologies enforcing separation • Logical name mappings in struts-config.xml • View --> Controller encapsulated in a form submit, matched to a form bean • Controller --> View via RequestDispatcer

36. JavaServer Faces • Where is JavaServer Faces coming from? • The need to provide rich UI components to page developers • The need for a standard set of components to ease learning (and enable tools support) • But UI components are not enough by themselves: • Event handling • Validation • Navigation • There needs to be enough there to beusable out of the box

37. JavaServer Faces • So what do we do about the overlap? • Use the parts that are helpful, ignore the parts that are not • The planned scenario: • Struts provides a JSF-compliant tag library that provides the functionality we know and love • Context-relative paths, URL rewriting, ... • Struts applications can migrate their UI to use Faces, one page at a time, with no changes to the Actions, form beans, or business logic • This is an entirely feasible endgame • Will be available with next EA release of JSF ...

38. Resources

39. Struts Resources • The Struts and Commons Web Sites: • http://jakarta.apache.org/struts/ • http://jakarta.apache.org/commons/ • Recent Books About Struts: • Cavaness, Chuck; Programming Jakarta Struts; O'Reilly • Goodwill, James; Mastering Jakarta Struts; John Wiley • Husted, Ted; Java Web Development With Struts; Manning • Spielman, Sue; The Struts Framework: Practical Guide for Programmers; Morgan Kaufman • Turner, James; Struts Kick Start; Sams

40. Q & A