Development Roadmap

This document outlines some of changes we expect to see in future releases of Struts.

This document is provided for discussion purposes only. All releases and changes to the codebase are subject to a vote of the Struts PMC.

The Struts development teams uses the Apache Bug Database (Bugzilla) to manage problem reports and enhancement requests. For your convenience, here are some common Bugzilla queries:

• Open reports
• Open reports with at least 3 votes
• Open problem reports
  • major problem reports
  • normal/minor problem reports
• Open enhancement reports
  • Patch Available
• Reports to be handled "LATER"

Releases in the 1.x series will focus on refactoring of existing functionality, with a continued emphasis on backward compatibility.

New features are being added to the Struts 1.x series, but only if backward compatability with the prior release can be retained. The 1.x API is evolving through a deprecate/replace/remove protocol. Developers are encouraged to stay current with the "best available" release and to observe deprecation warnings. Features are deprecated before removal, and deprecated features are ultimately removed.

The 1.x series is being refactored into the Struts subproject and several dependant subprojects. Each subproject is expected to be dependant on the Struts core for necessary functionality. Otherwise, the subproject should be hosted in another venue, such as Jakarta Commons or Jakarta Taglibs.

Popular third-party extensions that are in active use by the Struts Community may be considered as subprojects, such as those distributed through the Struts SourceForge site.

Throughout the 1.x series, there will be a continued emphasis on expanding unit test coverage for the framework. Bug reports should include a failing test case when possible. Proposals for new features should include a working test suite. (Creating features through Test Driven Development is strongly encouraged.)

Enhancement requests are logged in Bugzilla as they are suggested. The listing of an enhancement in Bugzilla does not imply that is being "planned", merely that some member of the community has suggested it, and the idea hasn't been ruled out (yet).

Future release milestones are provided for enhancements which are being actively planned or developed but may not be ready for the very next release. If a report has not been tagged for a specific milestone by a working developer, then it may never be implemented. When developers (including non-Committers) are actually working on an enhancement, they should re-tag it for a specific release milestone, such as "1.3.1" or "1.3.2".

If an enhancement has not been tagged for a specific target, feel free to start working on it yourself. Many of our best features have been contributed by developers, just like you. If you are working on an enhancement, post a note on the ticket that you are working on an enhancement and then post a patch as soon as possible. If the development effort doesn't succeed, post a note to the ticket explaining what problem you had creating the enhancement, so that other developers can explore alternatives.

These are some general ideas we have about what may happen in the Struts 1.x series. This is a whiteboard and everything here is subject to change.

• Struts 1.0.0 (complete) - Major refactoring of Struts internals to provide support for modules and a new "config" object series. Bundles Struts Tiles and Struts Validator into main distribution. The initial release of Struts EL is provided as an optional package.
• Struts 1.2.4 (complete) - Continued refactorings of the Struts 1.x product series.
  • Removed deprecations created in the 1.0 to 1.1 timeframe, and prior
  • Added support for wildcard mappings.
  • Other minor enhancements, improvements, and refactorings
• Struts 1.2.6 (complete) - Migrated repository to Subversion; update website.
• Struts 1.2.x (pending) - Minor enhancements, improvements, and refactorings only, as needed. New features should be added to the 1.3.x series.
• Struts 1.3.x (pending) - Enhancements to product base, based on existing features or codebases.
  • Divide distribution into subprojects
    • core, apps, el, faces, site, taglibs
    • flow, scripting (new)
  • Complete support for Maven builds (pending)
  • Move core to "Struts Chain" Request Processor (now in Contrib)
  • Move to Commons Resources (if available)
  • Enhance all configs to extend one configuration element from another, as is done with Tiles Definitions
• Struts 1.4.x - Enhancements to product base, based on undeveloped code.
  • Consider adding support for an Action context (which also might be based on the Commons Chain of Responsibility package).
  • Consider adding support for Porlets by specifying an alternate Request Processor catalog.
• Other potential enhancements for the 1.x.x series
  • Consider Cocoon Plugin
  • Consider Spring Plugin
  • Consider adopting several popular extensions, including:
    • Layout
    • SSL Ext
    • Stxx (XLST)
    • TestCase
    • Workflow

Struts 2.x (aka Struts "Next Generation") will include broader enhancements. We anticipate that the implementation will utilize the Servlet 2.4 / JSP 2.0 platform, and perhaps Java 1.5, but may optionally support earlier platforms.

We anticipate that Struts 2.x will rely on JSTL and the JavaServer Faces API as supporting technologies. However, the focus of the Struts framework will remain on the Controller aspect of a Model 2/MVC architecture. The core framework will continue to be both Model and View independent.

Development of Struts 2.x will include taking a completely fresh look at the internal architecture. The goal for 2.x will be to incorporate everything we've learned in the past years of Struts usage, and create something even better. Development will follow current best practices, like Test Driven Development, and rely on technologies like Maven for project management.

Of course, it is anticipated that the Struts team will continue to support the 1.x codebase for a long time with bugfixes and incremental enhancements. (Mainly because many of us will still be using it on our production sites!) Accordingly, it is anticipated that the development of the 2.x and 1.x series will occur in tandem. At some point, 2.x milestones may appear alongside new 1.x releases.

As Struts 1.x evolves, some (or all) target features may overlap. Target features for Struts 2.x include:

• Comprehensive unit test coverage for all core features
• Enhanced support for using Struts in large team environments.
• Transparent support for a portlet environment (JSR 168), with minimal-to-no changes in your business logic and pages.
• Direct support for JSTL/JSF taglibs and the JSF API
• Enhanced support for other presentation layers, such as XLST
• Enhanced support for scriptable Actions, using technologies like BSF or Jelly
• Refactoring for new technologies available on the Servlet 2.4/ JSP 2.0 platform

An early proposal for one possible implementation of Struts 2.x, "Struts Jericho", is available in the contrib folder.

There are three major issues with supporting JSR-168 (and I'm sure a bunch of smaller ones as well):

• Struts APIs assume servlet API objects (ServletContext, ServletRequest, ServletResponse), whereas JSR-168 talks aboutPortletContext, PortletRequest, and PortletResponse. We'd either need to change the calling sequence for Action.execute() -- problematic for backwards compatibility -- or fake it somehow in a portlet environment.
• The lifecycle of a portlet request is actually divided into two chunks -- processing and then rendering. From a Struts perspective, that means making sure that the first part of the request processor pipeline need to happen in the "process" part, and the forwarding to the resulting page needs to happen in the "render" part.
• Today, Struts owns the process of calculating URLs for pages and actions. Because it's in a webapp, it knows exactly what to do for the developer. However, in a portlet container it's actually the portal server that manages URLs, so a Struts-based portlet would need to interact with the portlet APIs for this purpose.

A strong goal should be that a Struts application should be usable either as a webapp or as a portlet, with little (ideally no) changes. Therefore, we should build whatever it takes to support this into the standard Struts distribution, which would then be used in both environments.

Struts is providing support for JavaServer Faces through the Struts Faces Integration Library. The Struts Faces tablib allows developers to migrate pages to JSF but retain use of their Actions. Pages can be migrated on a one-by-one basis. The Struts Faces taglib is still under development, and a 1.0.x release is forthcoming.

As JSF comes into broader use, it is expected that Struts developers will continue to offer enhancements to make it even easier to use Struts with JSF.

The SourceForge MyFaces team is in the process of joining the Apache Software Founcation. Once the Apache MyFaces team has access to the Apache TCK, it is expected to be recognized as a certified JSF implementation.

For more about Struts and JavaServer faces, see:

• Craig McClanahan's blog entry
• Our FAQ
• Java Server Faces Resources at JamesHomes.com

• Commons Chain of Responsiblity package
• CoRe Request Processor
• Release Plan 1.2.7
• struts-faces taglib

Next: Source Repository

Website updated from repository: 2004 OCT 23 by husted.

Javadocs updated from repository: 2004 OCT 15 by husted.