Transcript people.apache.org

The Struts Framework
Community
Craig McClanahan
BOF #1820 -- The Struts Framework Community
Agenda
Welcome
Struts 1.1 – New Features
What Does The Future Hold?
Questions and Answers
Beginning
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BOF #1820 -- The Struts Framework Community
Welcome
The "Struts Community" is growing ...
Users (STRUTS-USER mailing list has 1750
subscribers)
Downloads (1000/day first two weeks of March)
Plug-in and Add-on technologies
Publications and books
Awareness (try a Google search on "struts")
The future looks even brighter
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BOF #1820 -- The Struts Framework Community
Struts 1.1 – New Features
Jakarta Commons Libraries
DynaActionForm
Declarative Exception Handling
Nested Tag Library
PlugIn API
Multiple Application Support
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BOF #1820 -- The Struts Framework Community
Jakarta Commons Libraries
COMMONS-BEANUTILS
Pluggable type converters
Mapped properties
 contact.phone(Work)
DynaBeans
Transparently supported by BeanUtils and
PropertyUtils
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BOF #1820 -- The Struts Framework Community
Commons-Beanutils -- DynaBeans
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);
}
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BOF #1820 -- The Struts Framework Community
Jakarta Commons Libraries
COMMONS-LOGGING
Wrapper around any logging API
Intelligent discovery mechanism
Did I ask for a particular factory? Use it
Is Log4J available? Use it
Is JDK1.4 logging available? Use it
Default to "no-op" logger
Simple System.err logging implementation
available
Relies on underlying logging implementation for
configuration
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BOF #1820 -- The Struts Framework Community
Jakarta Commons Libraries
COMMONS-DBCP and COMMONS-POOL
Provide javax.sql.DataSource implementation
Connection timeouts
Both getConnection() methods supported
Idle connections can be released
For backwards compatibility,
org.apache.struts.util.GenericDataSource is a
wrapper around this
Bridges the JDBC API changes in JDK 1.4
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BOF #1820 -- The Struts Framework Community
DynaActionForm – 1
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
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BOF #1820 -- The Struts Framework Community
DynaActionForm – 2
<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>
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BOF #1820 -- The Struts Framework Community
Declarative Exception Handling – 1
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 ...
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BOF #1820 -- The Struts Framework Community
Declarative Exception Handling – 2
public ActionForward execute
(ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response)
throws Exception {
...
throw new PasswordExpiredException(...);
...
}
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BOF #1820 -- The Struts Framework Community
Declarative Exception Handling – 3
<action path="/logon" ...>
...
<exception key="expired.password"
type="o.a.s.w.e.ExpiredPasswordException"
path="/changePassword.jsp"/>
...
</action>
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BOF #1820 -- The Struts Framework Community
The "Nested" Tag Library – 1
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 ...
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BOF #1820 -- The Struts Framework Community
The "Nested" Tag Library – 2
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>
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BOF #1820 -- The Struts Framework Community
Plug-In 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;
}
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BOF #1820 -- The Struts Framework Community
Multiple Application Support – 1
Very popular user request for large scale
applications
Design goals:
Support multiple independent struts-config.xml
files in the same webapp
Sub-applications are identified by an
"application prefix" that follows the context path
Existing Struts-based applications should be
able to be installed individually, or as a subapplication, with no changes to the pages,
Actions, form beans, or other code
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BOF #1820 -- The Struts Framework Community
Multiple Application Support – 2
Implications of the design goals:
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"Default" sub-application with a zero-length
prefix (like the ROOT context in Tomcat)
"Context-relative" paths must now be treated as
"sub-application-relative"
ActionServlet initialization parameters migrate
to the struts-config.xml file
Controller must identify the relevant subapplication, and make its resources available
(as request attributes)
APIs must be reviewed for assumptions about
there being (for example) only one set of
ActionMappings
BOF #1820 -- The Struts Framework Community
Multiple Application Support – 3
The goals appear to have been achieved:
Please download the beta and help us by
testing your apps as sub-applications
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)
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BOF #1820 -- The Struts Framework Community
Current Status
Struts 1.1-beta-1 released on March 19, 2002
After the download counts referenced earlier
...
http://jakarta.apace.org/struts/
Please try it out with your own applications,
and report any compatibility (or other)
bugs:
http://nagoya.apache.org/bugzilla/
I anticipate at least one more beta, but there
might well be more
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It will be released when we're satisfied that
BOF #1820 -- The Struts Framework Community
What Does The Future Hold?
In the mean time, the Java world around web
applications is changing ...
Servlet 2.4 (JSR-154)
JSP 1.3 (JSR-152)
JSP Standard Tag Library 1.0 (JSR-52)
JavaServer Faces (JSR-127)
And new things are becoming popular ...
Web services
Portals
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Servlet 2.4
Some nice additions
Request lifecycle events
Request dispatcher events
But not likely to affect Struts in the near term
However, is it time to migrate Struts to be
based on Servlet 2.3 (and JSP 1.2)?
Filters and lifecycle listeners
Request and response wrappers
JSP Standard Tag Library ...
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BOF #1820 -- The Struts Framework Community
JSP 1.3
Expression Language
Available now in JSP Standard Tags Library
In JSP 1.3, 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"
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BOF #1820 -- The Struts Framework Community
JSP Standard Tag Library
Currently in beta, will be final in June
RI implemented at 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 plan
on utilizing these tag libraries
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BOF #1820 -- The Struts Framework Community
JavaServer Faces – 1
The most popular question at JavaOne 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 ...
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BOF #1820 -- The Struts Framework Community
JavaServer Faces – 2
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
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BOF #1820 -- The Struts Framework Community
JavaServer Faces – 3
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 be
usable out of the box
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BOF #1820 -- The Struts Framework Community
JavaServer Faces – 4
So what do we do about the overlap?
Use the parts that are helpful, ignore the parts
that are not
The ideal 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
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This is an entirely feasible endgame
BOF #1820 -- The Struts Framework Community
Questions and Answers
Phew, that's a lot of information ...
So, what's on your minds?
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BOF #1820 -- The Struts Framework Community
BOF #1820 -- The Struts Framework Community