Michael Rimov Centerline Computers Craig McClanahan Sun Microsystems O’Reilly Open Source...

transcript

Michael RimovCenterline Computers

Craig McClanahanSun Microsystems

O’Reilly Open Source ConventionJuly 7 - 11, 2003

Michael Rimov & Craig McClanahan

Introduction

Presentation Slides, Notes and Samples Available At:

http://www.centercomp.com/beyondstruts/

What Defines Struts?

• Lightweight Model 2 J2EE framework for the HTTP Servlet portion of the application.

• NOT Meant to dictate the entire J2EE implementation.

Model 2 Typical Flow

Controller Model

Browser

MVC Based Model 2 Architecture Diagram

Abbreviated Model

Controller

What Makes Struts So Extensible?

• Lightweight and Focused: Doesn’t Try To Do Everything.

• Well Designed: Very good separation of concerns, very clean coding implementation.

• Uses Java Reflection to allow freedom of objects.

Case Studies

• Struts and Expresso

• Struts and Macromedia Flash• Struts and XML• Struts and Java Server Faces

Case Study: Expresso 5http://www.jcorporate.com/

Case Study: Expresso 5

Controller

ExpressoController

ControllerResponse

DefaultJSP

Controller Extension:

• Provided Application Level Security Matrix

• Added in-request routing ability.• Provided mostly-Servlet Independent

flow of control.

Struts Action:

public ActionForward perform(ActionMapping mapping,ActionForm form,

HttpServletRequest request,

HttpServletResponse response)

Expresso Version:

protected void runPromptLoginState(ControllerRequest request, ControllerResponse response)

Model Extension:

• ControllerRequest / ControllerResponse objects.

• ControllerResponse is populated with Inputs/Outputs/Blocks/Transitions.

• Can use Struts Beans as well.• Added Database Access Layer

View Extension:

• Default UI Renderer• Customizable XSLT Processing

Capabilities.• Compatible with Struts Views.

Integration Experiences:

• Extremely supportive community• Reaped Performance Improvements• Partial Integrations still work well.• Easy to extend even the Struts internals.

Case Study: Macromedia Flashhttp://www.macromedia.com/software/flash

Case Study: Macromedia Flash

Controller

JSP / Flash

Integration Methods:

• XMLSocket and XML formatted pages.• LoadVariables and property formatted

pages.• NOT covering Flash Remoting

All Integration methods need some sort of template view system such as JSP or Velocity.

Start Page

• Tell Flash Where To Get Its Data.<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000"

codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,29,0" width="445" height="244">

</object>

XML Socket Method

• Create Flash Starting Page • Load initial data through the ‘data’

parameter. • On-submit, the movie opens an XML

Socket to the server and Struts.• Struts formats return data as XML.

XML Socket Method: Drawbacks

• XML Parsing on the Client Side.• XML Parsing on the Server Side• Expansion of Bandwidth

Load Variables Method

• Create Flash Starting Page • Load initial data through the ‘data’

parameter. • On-submit, the movie opens an http

request to the server.• Struts formats return data in a

“property=value” format.

Load Variables Method: Drawbacks

• Simple format of return data only.• Fancier formats require parsing again.

Similar drawbacks as XMLSocket.• Recommended you use simple beans for

rendering only• Flash 6 Only

Quick ActionScript Sampleon (release) {

LoadVars lv = new LoadVars();

LoadVars receiveVars = new LoadVars();

lv.loginName=LoginName;

lv.password = Password; receiveVars.onLoad = processResult; //Not Shown Here

lv.sendAndLoad(data,receiveVars,"POST");

Introducing Craig McClanahan

Case Study: Struts and XML

• Most Struts apps generate HTML– With the Struts HTML tags (JSP)– With alternative presentation systems like

Velocity and Freemarker

• Templates accessed via RequestDispatcher. forward() call, but there's another way ...

• Action.execute() -- return null to indicate that the response has been created already

• Opens the door to XML-based output

Struts and XML: General Approach

• Form submitted to Action, as usual

• Action creates result beans, as usual, or renders XML objects

• Action renders XML directly (or forwards to an XML-generating template)

• Template incorporates dynamic data from result beans or rendered XML objects

• XSLT stylesheet(s) transform to HTML or other markup language

Struts and XML: Resources• JSP and JSTL can be used directly instead

of HTML tags

• Two Popular Struts and XML Extensions:– StrutsCX

• Http://it.cappuccinonet.com/strutscx/

– Stxx• http://www.openroad.ca/opencode/

• More information online, on the Struts Resources pages:

• http://jakarta.apache.org/struts/resources/

Case Study: Struts and JavaServer Faces

Case Study: JavaServer Faces

• What Is JavaServer Faces?– Server-side user interface component

framework for Java-based web apps– Under development in the Java Community

Process (JSR-127)– Currently at Public Draft 2 in the process– Early Access 4 of Reference

Implementation is available– http://java.sun.com/j2ee/javaserverfaces/

JavaServer Faces: Goals

• Accessible to corporate developers

• Usable via tools and by hand• Usable with and without JSP• Usable with and without HTML• Usable with servlet and portlet APIs• Can be adopted immediately

– Minimum platform: Servlet 2.3, JSP 1.2– Final 1.0 version: 4QCY2003

JavaServer Faces: Features

• Extensible UI component model

• Flexible rendering model– Standard HTML renderkit included

• Event and listener model• Validation framework• Basic page navigation support• Internationalization and accessibility

JavaServer Faces: Sample Page<f:use_faces>

<h:form formName=”logonForm”>

<h:panel_grid columns=”2”>

<h:output_text value=”Username:”/>

<h:input_text id=”username” length=”16”

valueRef=”logonBean.username”/>

<h:output_text value=”Password:”/>

<h:input_secret id=”password”

length=”16”

valueRef=”logonBean.password”/>

JavaServer Faces: Sample Page <h:command_button type=”submit”

label=”Log On”

actionRef=”logonBean.logon”/>

<h:command_button type=”reset”

label=”Reset”/>

</h:panel_grid>

</h:form>

</f:use_faces>

JavaServer Faces: Managed Bean<managed-bean>

<managed-bean-name>

logonBean

</managed-bean-name>

<managed-bean-class>

mypackage.mybeans.LogonBean

</managed-bean-class>

<managed-bean-scope>

request

</managed-bean-scope>

</managed-bean>

JavaServer Faces: Bean Classpublic class LogonBean { // No base class!

// The usual property getters/setters

public String getUsername() { ... }

public void setUsername(String username)

{ ... }

public String getPassword() { ... }

public void setPassword(String password)

{ ... }

JavaServer Faces: Bean Class ...

// Getter returns “Action” for button

public Action getLogon() {

// Anonymous inner class used here

return new Action() {

public String invoke() {

// Invoke method on bean class

return (logon());

JavaServer Faces: Bean Class ...

protected String logon() {

// Business logic can access form fields

// as instance variables

if (username/password combo is ok) {

return (“success”); // Logical outcome

} else {

return (null);

JavaServer Faces: Navigation<navigation-rule>

// Wildcard and global patterns ok

<from-tree-id> /logon.jsp </from-tree-id>

<navigation-case>

<from-action-ref> // Optional

logonBean.logon </from-action-ref>

<from-outcome> // Optional

success </from-outcome>

<to-tree-id>

/mainmenu.jsp </to-tree-id>

</navigation-case>

</navigation-rule>

JavaServer Faces and Struts

• So, is JavaServer Faces Replacing Struts?– NO!!!– Struts 1.1 is and remains very popular– Struts will continue to innovate & advance

• Then, can I use them together?– YES!!!– With the Struts-Faces Integration Library

• http://jakarta.apache.org/builds/jakarta-struts/

release/struts-faces/

JavaServer Faces And Struts

• Replaces Struts HTML Tags With More Powerful JavaServer Faces Components

• Continue to use struts-config.xml file• Integrates with Struts RequestProcessor• Supports Standard Struts Features:

– Form Beans and Actions– Validator Framework– Tiles Framework (coming soon ...)

JavaServer Faces and Struts

• To use the library with an existing app:– Get the JavaServer Faces RI– Drop it and struts-faces.jar into your

/WEB-INF/lib directory– Change HTML tags on one page at a time– Tweak your forward paths, and– Don't touch your form beans or actions

• MVC works ... what a concept :-).

Conclusion

Presentation Information

Michael Rimov: rimovm@centercomp.com

Craig McClanahan:craigmcc@apache.org

Slides, Notes and Sample Code Availablehttp://www.centercomp.com/beyondstruts/

Michael Rimov Centerline Computers Craig McClanahan Sun Microsystems O’Reilly Open Source...

Documents