JBOSS Seam A technical overview

Presentation on theme: "JBOSS Seam A technical overview"— Presentation transcript:

Slide1
JBOSS Seam
A technical overview
9/10/2007
1
© Dipl.-Inform. Volker Reichel, VRSoft, 2007
Slide2
Foreword
This presentation is not intended to provide a full description of all the features available in Seam.It is the authors intend to present the key features and give some basic configuration hints in order to get a smooth start with Seam
Seam can be downloaded from http://labs.jboss.com/jbossseam/
For feedback please send mail to seam@vrsoft.de9/10/2007
2
Slide3
Introduction
Seam is a web application framework based on JavaServer Faces (JSF) which aims to simplify web development by reducing XML configuration tasks and Java helper classes.
Seam web applications can be deployed in EJB3 containers but this is not a must!Seam provides an embedded EJB3 container
Seam does not need EJB3 features at all. It works fine with Plain Old Java Objects (POJO) and Java Persistence Architecture
(JPA).
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Slide4
Architecture
Seam
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Slide5
Architecture
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Slide6
Deployment Scenarios
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Slide7
Deployment Scenarios
Decide on how your Seam application will be deployed
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Slide8
Types of components
Seam
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Slide9
Seam Component Types
Form Backing Beans (Java classes)Directly supported by JSF
The targets of JSF formsBring data into JSF pagesAction Listener (Java classes)
Target of form submission & linksImplementation of the MVC controllerPerforming business logicBrowser Accessible Components
(Java classes)
Accessing EJBs or POJOs via JavaScript (AJAX)
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Slide10
Usage Best Practices
POJO
Stateless
Session BeanStatefullSession Bean
Entity
Bean
Message Driven
Bean
Component
++
--
++
++
--
Backing Bean
++
++
++
--
--
Action Listener
--
++
++
--
--
Browser Comp.
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Seam Features
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Slide12
Seam features
Simplified Programming ModelNo more managed beansExtended state management
Supports structured pageflowPredefined flexible security componentSupports AjaxNo need to have an EJB3 container
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Slide13
State management
JBoss Seam
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Slide14
Seam Component Contexts
Contexts provide a mechanism for data access. Seam provides the following contexts:
SessionSpans a HTTP-SessionApplication
Spans as long as the web application is runningRequestSpans as long as the current HTTP-Request is runningPageData belongs to the page
Conversation
Spans across several HTTP-Requests
Workspace
Spans several sessions (i.e. users) and conversations
(more like a business process)
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Slide15
Conversation Types
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Implicit
Explicit
are default
each request is
wrapped in an implicit
conversation
JSF
Page
pages.xml
Java
@Begin / @End
on method
f:param
conversationPropagation
or

@propagation i
n

seam:link
-Element
@action=“#{
conversation.XXXX
}”
in <page>-Element
Conversation modes:

Conversation.begin

Conversation.end

Conversation.join

Conversation.nest
Slide16
Request Procession
JBoss Seam
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Slide17
JSF Request Processing Phases
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Restore
View
Apply Request Values
Process
Validations
Update
Model
Values
Invoke
Application
Render
Response
Determine target view & create / restore it
Update managed beans
Run application callbacks / action listeners
Refresh the view
Run registered
validators
Update UI components with request data
Slide18
Structured Pageflow
JBoss Seam
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Slide19
Structured Pageflow
Seams Pageflow uses JBoss’s jBPMs
Process Definition Language (jPDL)jPDL has a different syntax than BPEL
jPDL can be used to describe pageflowsjPDL is different from <navigation-rule>-Syntax
jPDL
consists of
States
Events / Outcomes
Transitions
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Slide20
JPDL Pageflow Features
Can be mixed with JSF navigationBy default disables “back” button functionalityGood for modal or wizard-driven UI flows
Good separation of flow and UI
9/10/2007© Dipl.-Inform. Volker Reichel, VRSoft, 2007
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Slide21
Enabeling Pageflow (jBPM)
Add
<component class=“org.jboss.seam.core.Jbpm
”>
<property name=“
pageflowDefinitions
”>
<value>
flow_A.jpdl.xml
</value>
<value>
flow_B.jpdl.xml
</value>
</property>
</component>
to
components.xml
Put the flow file (
*.
jpdl.xml
) into the web apps
classpath
. For security reasons flows should be stored in
<
webapp
>/WEB-INF/classes
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Slide22
Mapping jPDL
To JSF/Seam9/10/2007
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State A
State B
Event E
Outcome X
JSF View
A
JSF View
B
ActionListener.actionMethod
Method return value
jPDL
JSF/Seam
Slide23
Security
Seam
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Security
Provided as predefined component (identity)Delegates implementation to user-defined Java class
Supports declarative security settingsi.e. JRules (drools.jar)Fine-grained security
Finest level is method & instanceNeeds faceletsNeeds
jboss-seam-ui.jar
in
classpath
Needs SeamFaceletViewHandler
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Slide25
Protection Levels
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Pages
Components
Methods
<page …>
<restrict>
</restrict>
</page>
<page
login-required=“true”>
…
</page>
pages.xml
@Restrict annotation
in Java Code either on
class or individual method
*.java
Slide26
SEAM Application Configuration
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Slide27
What needs to be done to get a Seam application running?
Configure EJB componentsSeamEJBInterceptor
EJB Beans declarations (optional)Enable optional Seam components
Security
Pageflow
jBPM
Define / Configure Behavior
Actions
Navigation
Error Handling
Conversation Management
Security
continued
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Slide28
What needs to be done to get a Seam application running?
Bundle Seam core libraries with your application (ear or war)
The details will be given laterConfigure Facelets
FaceletViewHandler (for basic Seam features)
SeamFaceletViewHandler (enhanced JSF-EL, security)
Configure web application environment
Seam JSF Phase Listener
Seam Servlet Listener
Configure Seam features (optional)

SeamFilter & Filter Mapping prepares Exception Handling & Validation

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Slide29
1. Bundle Seam core libraries
If you are developing a web application using a war-archive then put
jboss-seam.jar in webapp
/WEB-INF/lib directoryIf you are developing an enterprise application (ear) then put jboss-seam.jar in root of the EAR archive and reference the
jboss-seam.jar
module as shown on the next slide in your
application.xml
Replace the text in the highlighted regions according with your application
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Slide30
Application.xml
<?xml version="1.0" encoding="UTF-8"?><application
xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/application_5.xsd"
version="5">
<display-name>
MyApp
</display-name>

<module>
<web>
<web-
uri
>
myapp.war
</web-
uri
>
<context-root>/
myapp
</context-root>
</web>
</module>

<module>
<
ejb
>
myapp-ejb.jar
</
ejb
>
</module>


<module>
<java>jboss-seam.jar</java>
</module>
</application>
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Slide31
2. Configure Facelets
PutJavaServer
Faces (jsf-facelets.jar)Expression Language API (el-api.jarEL-Reference Implementation (el-ri.jar)into your
webapp classpath i.e. WEB-INF/lib
Set view-handler in
faces-config.xml
to
com.sun.facelets.FaceletViewHandler
If you want basic
Facelet
support
org.jboss.seam.ui.facelet.SeamFacletViewHandler
If you want enhanced features like JSF EL, validation, security
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Slide32
3. Configure web application
EnvironmentSeam needs to register itself with JSF in order to receive events during request processing. Therefore we have to add a SeamPhaseListener to
faces-config.xml.
<faces-
config
>
…
<lifecycle>
<phase-listener>

org.jboss.seam.jsf.SeamPhaseListener
</phase-listener>
</lifecycle>
…
</faces-
config
>
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Slide33
3. Configure web application
Environment
Seam contexts and core services are managed by a SeamServletListener which you have to setup in web.xml.
<web-app>
…
<listener>
<listener-class>

org.jboss.seam.servlet.SeamListener
</listener-class>
</listener>
…
</web-app>
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Slide34
4. Configure Seam features
Some Seam features which can be configured in
components.xml need a basic web filter you have to add the definitions shown on the next slide to
web.xml
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Slide35
<web-app> …
<servlet>
<servlet-name>Seam Resource Servlet</servlet-name>
<servlet-class>org.jboss.seam.servlet.ResourceServlet</servlet
-class>
</
servlet
>
<
servlet
-mapping>
<
servlet
-name>Seam Resource Servlet</
servlet
-name>
<
url
-pattern>/seam/resource/*</
url
-pattern>
</
servlet
-mapping>
<filter-name>Seam Filter</filter-name>
<filter-class>
org.jboss.seam.web.SeamFilter
</filter-class>
</filter>
<filter-mapping>
<filter-name>Seam Filter</filter-name>
<
url
-pattern>/*</
url
-pattern>
</filter-mapping>
…</web-app>
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web.xml
Slide36
4. Configure Seam features
ValidationMulti-part form submission
SecurityAnd other features are only available when jboss-seam-ui.jar is in the
classpath of the webapp.Therefore you have to put
jboss-seam-ui.jar
into
webapp
/WEB-INF/lib
directory.
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Slide37
5. Configure EJB components
In order to use Seam EJB components you have to install the Seam EJB Interceptor which is done your
ejb-jar.xml file.
<
ejb
-jar>
…
<assembly-descriptor>
<interceptors>
<interceptor>
<interceptor-class>
org.jboss.seam.ejb.SeamInterceptor
</interceptor-class>
</interceptor>
<interceptor-binding>
<
ejb
-name>*</
ejb
-name>
<interceptor-class>
org.jboss.seam.ejb.SeamInterceptor
</interceptor-class>
</interceptor-binding>
</assembly-descriptor>
…
</
ejb
-jar>
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Slide38
6. Enable Optional Seam
componentsStep 5 is a necessary prerequisite for this step!
components.xml is used to configure Seam components. Either predefined or your own components.Typically you will only enable predefined components like security here.
Your own components are made accessible via the @Name annotation in your source! But if you like you can configure your components here also.
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Slide39
6. Enable Optional Seam
components
If you are going with EJB 3.0 you have to provide a JNDI pattern for the lookup of these EJBs.
<components>
…
<component name=“
org.jboss.seam.core.init
”>
<property name=“
jndiPattern
”>
myApp
/#{
ejbName
}/local</property>
</component>
…
</components>
#{
ejbName
} will expand
to your EJB’s name during runtime
Make sure

seam.properties
is in your META-INF directory. The file does not need to have any contents but if it is missing the automatic scanning for components will not work!
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Slide40
7. Define / Configure Behavior
Behavior is specified in
pages.xml which is optionalThere arePage actionsTrigger activity before a page is invoked
Page navigationSame as navigation rules in faces-config.xml

Since
faces-config.xml
is for Facelets page navigation should be defined here for consistency
Error handling
redirect to a page, show JSF message, end conversation
Manage conversation properties
Start, end
Security
declare security constraints on pages, roles, users
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Slide41
Simplified Programming Model
Seam
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Slide42
JSF vs. SEAM
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JSF Page
JSF Page
JSF Page
JSF Page
POJO Facade
POJO Facade
Session EJB
Entity EJB
Session EJB
Entity EJB
Managed Bean
Automatically wrapped in Managed Bean
Slide43
Injection & Bijection
Seam Features
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Slide44
What is injection /
Bijection?Injection allows passing information from outside into an object
Injection is executed typically once during initialization of the objectBijection passes information into an object and allows information to be exported from an object
Bijection happens whenever needed not only at initialization timeBijections is controlled via @in / @out annotations
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Slide45
Special Notes for JBOSS Application Server
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Slide46
JBOSS 4.2.x / JBOSS 5.X
SituationJBoss 4.2.x and 5.x are using JSF Reference Implementation (which is JSF 1.2) while 4.0.5 uses Apache MyFaces
SolutionMake sure “MyFaces” listener (org.apache.myfaces.webapp.StartupServletContextListener) is commented out in the listener sections of web.xml
Remove “el-ri.jar” and “el-api.jar” from application.xmlMake sure you are using the application and lifecycle settings provided on the next slide. Please check the namespace declaration and version attribute!
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Slide47
Sample faces-config.xml for 4.2.x and 5.x
<faces-config version="1.2"
xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-facesconfig_1_2.xsd">
<application>
<el-resolver>
org.jboss.seam.jsf.SeamELResolver
</el-resolver>
</application>
<lifecycle>
<phase-listener>

org.jboss.seam.jsf.SeamPhaseListener
</phase-listener>
</lifecycle>

</faces-
config
>
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Slide48
Resources
SoftwareJBoss Seam
http://labs.jboss.com/jbossseamJBoss AS http://labs.jboss.com/jbossas
BooksPractical JBoss Seam Projects, Jim Farley, Apress
JBoss Seam Simplicity and Power Beyond Java EE
, Michael
Juntao
Yuan & Thomas
Heute
, Prentice Hall
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Slide49
Revision history
02.09.2007
Initial version
03.09.2007Review
9/10/2007
49

JBOSS Seam A technical overview

JBOSS Seam A technical overview

Presentation on theme: "JBOSS Seam A technical overview"— Presentation transcript:

JBOSS Seam A technical overview - Description

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