Configuration is a very boring topic and an extremely tedious pastime. Unfortunately, several lines of XML are required to integrate Seam into your JSF implementation and servlet container. There's no need to be too put off by the following sections; you'll never need to type any of this stuff yourself, since you can just copy and paste from the example applications!
First, let's look at the basic configuration that is needed whenever we use Seam with JSF.
Of course, you need a faces servlet!
<servlet>
<servlet-name>Faces Servlet</servlet-name>
<servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Faces Servlet</servlet-name>
<url-pattern>*.seam</url-pattern>
</servlet-mapping>(You can adjust the URL pattern to suit your taste.)
In addition, Seam requires the following entry in your web.xml file:
<listener>
<listener-class>org.jboss.seam.servlet.SeamListener</listener-class>
</listener>This listener is responsible for bootstrapping Seam, and for destroying session and application contexts.
Some JSF implementations have a broken implementation of server-side state saving that interferes with Seam's conversation propagation. If you have problems with conversation propagation during form submissions, try switching to client-side state saving. You'll need this in web.xml:
<context-param>
<param-name>javax.faces.STATE_SAVING_METHOD</param-name>
<param-value>client</param-value>
</context-param>If you want follow our advice and use facelets instead of JSP, add the following lines to faces-config.xml:
<application>
<view-handler>com.sun.facelets.FaceletViewHandler</view-handler>
</application>And the following lines to web.xml:
<context-param>
<param-name>javax.faces.DEFAULT_SUFFIX</param-name>
<param-value>.xhtml</param-value>
</context-param>The Seam Resource Servlet provides resources used by Seam Remoting, captchas (see the security chapter) and some JSF UI controls. Configuring the Seam Resource Servlet requires the following entry in web.xml:
<servlet>
<servlet-name>Seam Resource Servlet</servlet-name>
<servlet-class>org.jboss.seam.servlet.SeamResourceServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Seam Resource Servlet</servlet-name>
<url-pattern>/seam/resource/*</url-pattern>
</servlet-mapping>Seam doesn't need any servlet filters for basic operation. However, there are several features which depend upon the use of filters. To make things easier for you guys, Seam lets you add and configure servlet filters just like you would configure other built-in Seam components. To take advantage of this feature, we must first install a master filter in web.xml:
<filter>
<filter-name>Seam Filter</filter-name>
<filter-class>org.jboss.seam.servlet.SeamFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>Seam Filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>The Seam master filter must be the first filter specified in web.xml. This ensures it is run first.
Adding the master filter enables the following built-in filters.
This filter provides the exception mapping functionality in pages.xml (almost all applications will need this). It also takes care of rolling back uncommitted transactions when uncaught exceptions occur. (According to the Java EE specification, the web container should do this automatically, but we've found that this behavior cannot be relied upon in all application servers. And it is certainly not required of plain servlet engines like Tomcat.)
By default, the exception handling filter will process all requests, however this behavior may be adjusted by adding a <web:exception-filter> entry to components.xml, as shown in this example:
<components xmlns="http://jboss.com/products/seam/components"
xmlns:web="http://jboss.com/products/seam/web">
<web:exception-filter url-pattern="*.seam"/>
</components>url-pattern — Used to specify which requests are filtered, the default is all requests.
This filter allows Seam to propagate the conversation context across browser redirects. It intercepts any browser redirects and adds a request parameter that specifies the Seam conversation identifier.
The redirect filter will process all requests by default, but this behavior can also be adjusted in components.xml:
<web:redirect-filter url-pattern="*.seam"/>
url-pattern — Used to specify which requests are filtered, the default is all requests.
This feature is necessary when using the Seam file upload JSF control. It detects multipart form requests and processes them according to the multipart/form-data specification (RFC-2388). To override the default settings, add the following entry to components.xml:
<web:multipart-filter create-temp-files="true"
max-request-size="1000000"
url-pattern="*.seam"/>create-temp-files — If set to true, uploaded files are written to a temporary file (instead of held in memory). This may be an important consideration if large file uploads are expected. The default setting is false.
max-request-size — If the size of a file upload request (determined by reading the Content-Length header in the request) exceeds this value, the request will be aborted. The default setting is 0 (no size limit).
url-pattern — Used to specify which requests are filtered, the default is all requests.
Sets the character encoding of submitted form data.
This filter is not installed by default and requires an entry in components.xml to enable it:
<web:character-encoding-filter encoding="UTF-16"
override-client="true"
url-pattern="*.seam"/>encoding — The encoding to use.
override-client — If this is set to true, the request encoding will be set to whatever is specified by encoding no matter whether the request already specifies an encoding or not. If set to false, the request encoding will only be set if the request doesn't already specify an encoding. The default setting is false.
url-pattern — Used to specify which requests are filtered, the default is all requests.
If RichFaces is used in your project, Seam will install the RichFaces Ajax filter for you, making sure to install it before all other built-in filters. You don't need to install the RichFaces Ajax filter in web.xml yourself.
To override the default settings, add the following entry to components.xml. The options are the same as those specified in the Ajax4jsf Developer Guide:
<web:ajax4jsf-filter force-parser="true"
enable-cache="true"
log4j-init-file="custom-log4j.xml"
url-pattern="*.seam"/>force-parser — forces all JSF pages to be validated by Richfaces's XML syntax checker. If false, only AJAX responses are validated and converted to well-formed XML. Setting force-parser to false improves performance, but can provide visual artifacts on AJAX updates.
enable-cache — enables caching of framework-generated resources (e.g. javascript, CSS, images, etc). When developing custom javascript or CSS, setting to true prevents the browser from caching the resource.
log4j-init-file — is used to setup per-application logging. A path, relative to web application context, to the log4j.xml configuration file should be provided.
url-pattern — Used to specify which requests are filtered, the default is all requests.
Requests sent direct to some servlet other than the JSF servlet are not processed through the JSF lifecycle, so Seam provides a servlet filter that can be applied to any other servlet that needs access to Seam components.
This filter allows custom servlets to interact with the Seam contexts. It sets up the Seam contexts at the beginning of each request, and tears them down at the end of the request. You should make sure that this filter is never applied to the JSF FacesServlet. Seam uses the phase listener for context management in a JSF request.
This filter is not installed by default and requires an entry in components.xml to enable it:
<web:context-filter url-pattern="/media/*"/>
url-pattern — Used to specify which requests are filtered, the default is all requests. If the url-pattern is specified for the context filter, then the filter will be enabled (unless explicitly disabled).
The context filter expects to find the conversation id of any conversation context in a request parameter named conversationId. You are responsible for ensuring that it gets sent in the request.
You are also responsible for ensuring propagation of any new conversation id back to the client. Seam exposes the conversation id as a property of the built in component conversation.
Seam can install your filters for you, allowing you to specify where in the chain your filter is placed (the servlet specification doesn't provide a well defined order if you specify your filters in a web.xml). Just add the @Filter annotation to your Seam component (which must implement javax.servlet.Filter):
@Startup
@Scope(APPLICATION)
@Name("org.jboss.seam.web.multipartFilter")
@BypassInterceptors
@Filter(within="org.jboss.seam.web.ajax4jsfFilter")
public class MultipartFilter extends AbstractFilter {Adding the @Startup annotation means thar the component is available during Seam startup; bijection isn't available here (@BypassInterceptors); and the filter should be further down the chain than the RichFaces filter (@Filter(within="org.jboss.seam.web.ajax4jsfFilter")).
We need to apply the SeamInterceptor to our Seam components. The simplest way to do this across an entire application is to add the following interceptor configuration in ejb-jar.xml:
<interceptors>
<interceptor>
<interceptor-class>org.jboss.seam.ejb.SeamInterceptor</interceptor-class>
</interceptor>
</interceptors>
<assembly-descriptor>
<interceptor-binding>
<ejb-name>*</ejb-name>
<interceptor-class>org.jboss.seam.ejb.SeamInterceptor</interceptor-class>
</interceptor-binding>
</assembly-descriptor>
Seam needs to know where to go to find session beans in JNDI. One way to do this is specify the @JndiName annotation on every session bean Seam component. However, this is quite tedious. A better approach is to specify a pattern that Seam can use to calculate the JNDI name from the EJB name. Unfortunately, there is no standard mapping to global JNDI defined in the EJB3 specification, so this mapping is vendor-specific. We usually specify this option in components.xml.
For JBoss AS, the following pattern is correct:
<core:init jndi-name="myEarName/#{ejbName}/local" />Where myEarName is the name of the EAR in which the bean is deployed.
Outside the context of an EAR (when using the JBoss Embeddable EJB3 container), the following pattern is the one to use:
<core:init jndi-name="#{ejbName}/local" />You'll have to experiment to find the right setting for other application servers. Note that some servers (such as GlassFish) require you to specify JNDI names for all EJB components explicitly (and tediously). In this case, you can pick your own pattern ;-)
In an EJB3 environment, we recommend the use of a special built-in component for transaction management, that is fully aware of container transactions, and can correctly process transaction success events registered with the Events component. If you don't add this line to your components.xml file, Seam won't know when container-managed transactions end:
<transaction:ejb-transaction/>
There is one final item you need to know about. You must place a seam.properties, META-INF/seam.properties or META-INF/components.xml file in any archive in which your Seam components are deployed (even an empty properties file will do). At startup, Seam will scan any archives with seam.properties files for seam components.
In a web archive (WAR) file, you must place a seam.properties file in the WEB-INF/classes directory if you have any Seam components included here.
That's why all the Seam examples have an empty seam.properties file. You can't just delete this file and expect everything to still work!
You might think this is silly and what kind of idiot framework designers would make an empty file affect the behavior of their software?? Well, this is a workaround for a limitation of the JVM—if we didn't use this mechanism, our next best option would be to force you to list every component explicitly in components.xml, just like some other competing frameworks do! I think you'll like our way better.
If you're running in a Java EE 5 environment, this is all the configuration required to start using Seam!
Once you've packaged all this stuff together into an EAR, the archive structure will look something like this:
my-application.ear/
jboss-seam.jar
lib/
jboss-el.jar
META-INF/
MANIFEST.MF
application.xml
my-application.war/
META-INF/
MANIFEST.MF
WEB-INF/
web.xml
components.xml
faces-config.xml
lib/
jsf-facelets.jar
jboss-seam-ui.jar
login.jsp
register.jsp
...
my-application.jar/
META-INF/
MANIFEST.MF
persistence.xml
seam.properties
org/
jboss/
myapplication/
User.class
Login.class
LoginBean.class
Register.class
RegisterBean.class
...You should declare jboss-seam.jar as an ejb module in META-INF/application.xml; jboss-el.jar should be placed in the EAR's lib directory (putting it in the EAR classpath.
If you want to use jBPM or Drools, you must include the needed jars in the EAR's lib directory.
If you want to use facelets (our recommendation), you must include jsf-facelets.jar in the WEB-INF/lib directory of the WAR.
If you want to use the Seam tag library (most Seam applications do), you must include jboss-seam-ui.jar in the WEB-INF/lib directory of the WAR. If you want to use the PDF or email tag libraries, you need to put jboss-seam-pdf.jar or jboss-seam-mail.jar in WEB-INF/lib.
If you want to use the Seam debug page (only works for applications using facelets), you must include jboss-seam-debug.jar in the WEB-INF/lib directory of the WAR.
Seam ships with several example applications that are deployable in any Java EE container that supports EJB 3.0.
I really wish that was all there was to say on the topic of configuration but unfortunately we're only about a third of the way there. If you're too overwhelmed by all this tedious configuration stuff, feel free to skip over the rest of this section and come back to it later.
Seam is useful even if you're not yet ready to take the plunge into EJB 3.0. In this case you would use Hibernate3 or JPA instead of EJB 3.0 persistence, and plain JavaBeans instead of session beans. You'll miss out on some of the nice features of session beans but it will be very easy to migrate to EJB 3.0 when you're ready and, in the meantime, you'll be able to take advantage of Seam's unique declarative state management architecture.
Seam JavaBean components do not provide declarative transaction demarcation like session beans do. You could manage your transactions manually using the JTA UserTransaction or declaratively using Seam's @Transactional annotation. But most applications will just use Seam managed transactions when using Hibernate with JavaBeans.
The Seam distribution includes a version of the booking example application that uses Hibernate3 and JavaBeans instead of EJB3, and another version that uses JPA and JavaBeans. These example applications are ready to deploy into any J2EE application server.
Seam will bootstrap a Hibernate SessionFactory from your hibernate.cfg.xml file if you install a built-in component:
<persistence:hibernate-session-factory name="hibernateSessionFactory"/>
You will also need to configure a managed session if you want a Seam managed Hibernate Session to be available via injection.
<persistence:managed-hibernate-session name="hibernateSessionFactory"
session-factory="#{hibernateSessionFactory}"/>Seam will bootstrap a JPA EntityManagerFactory from your persistence.xml file if you install this built-in component:
<persistence:entity-manager-factory name="entityManagerFactory"/>
You will also need to configure a managed persistence context if you want a Seam managed JPA EntityManager to be available via injection.
<persistence:managed-persistence-context name="entityManager"
entity-manager-factory="#{entityManagerFactory}"/>We can package our application as a WAR, in the following structure:
my-application.war/
META-INF/
MANIFEST.MF
WEB-INF/
web.xml
components.xml
faces-config.xml
lib/
jboss-seam.jar
jboss-seam-ui.jar
jboss-el-api.jar
jboss-el.jar
jsf-facelets.jar
hibernate3.jar
hibernate-annotations.jar
hibernate-validator.jar
...
my-application.jar/
META-INF/
MANIFEST.MF
seam.properties
hibernate.cfg.xml
org/
jboss/
myapplication/
User.class
Login.class
Register.class
...
login.jsp
register.jsp
...If we want to deploy Hibernate in a non-EE environment like Tomcat or TestNG, we need to do a little bit more work.
It is possible to use Seam completely outside of an EE environment. In this case, you need to tell Seam how to manage transactions, since there will be no JTA available. If you're using JPA, you can tell Seam to use JPA resource-local transactions, ie. EntityTransaction, like so:
<transaction:entity-transaction entity-manager="#{entityManager}"/>If you're using Hibernate, you can tell Seam to use the Hibernate transaction API like this:
<transaction:hibernate-transaction session="#{session}"/>Of course, you'll also need to define a datasource.
A better alternative is to use JBoss Embedded to get access to the EE APIs.
JBoss Embedded lets you run EJB3 components outside the context of the Java EE 5 application server. This is especially, but not only, useful for testing.
The Seam booking example application includes a TestNG integration test suite that runs on JBoss Embedded via SeamTest.
The booking example application may even be deployed to Tomcat.
Embedded JBoss must by installed into Tomcat for Seam applications to run correctly on it. Embedded JBoss can be downloaded here. The process for installing Embedded JBoss into Tomcat 6 is quite simple. First, you should copy the JBoss Embedded JARs and configuration files into Tomcat.
Copy all files and directories under the Embedded JBoss bootstrap and lib directories, except for the jndi.properties file, into the Tomcat lib directory.
Remove the annotations-api.jar file from the Tomcat lib directory.
Next, two configuration files need to be updated to add Embedded JBoss-specific functionality.
Add the Embedded JBoss listener to conf/server.xml. It should appear after all other listeners in the file.
<Listener className="org.jboss.embedded.tomcat.EmbeddedJBossBootstrapListener" />
WAR file scanning should be enabled by adding a listener to conf/context.xml.
<Listener className="org.jboss.embedded.tomcat.WebinfScanner" />
For more configuration options, please see the Embedded JBoss Tomcat integration wiki entry.
The archive structure of a WAR-based deployment on an servlet engine like Tomcat will look something like this:
my-application.war/
META-INF/
MANIFEST.MF
WEB-INF/
web.xml
components.xml
faces-config.xml
lib/
jboss-seam.jar
jboss-seam-ui.jar
jboss-el-api.jar
jboss-el.jar
jsf-facelets.jar
jsf-api.jar
jsf-impl.jar
...
my-application.jar/
META-INF/
MANIFEST.MF
persistence.xml
seam.properties
org/
jboss/
myapplication/
User.class
Login.class
LoginBean.class
Register.class
RegisterBean.class
...
login.jsp
register.jsp
...Most of the Seam example applications may be deployed to Tomcat by running ant deploy.tomcat.
Seam's jBPM integration is not installed by default, so you'll need to enable jBPM by installing a built-in component. You'll also need to explicitly list your process and pageflow definitions. In components.xml:
<bpm:jbpm>
<bpm:pageflow-definitions>
<value>createDocument.jpdl.xml</value>
<value>editDocument.jpdl.xml</value>
<value>approveDocument.jpdl.xml</value>
</bpm:pageflow-definitions>
<bpm:process-definitions>
<value>documentLifecycle.jpdl.xml</value>
</bpm:process-definitions>
</bpm:jbpm>No further special configuration is needed if you only have pageflows. If you do have business process definitions, you need to provide a jBPM configuration, and a Hibernate configuration for jBPM. The Seam DVD Store demo includes example jbpm.cfg.xml and hibernate.cfg.xml files that will work with Seam:
<jbpm-configuration>
<jbpm-context>
<service name="persistence">
<factory>
<bean class="org.jbpm.persistence.db.DbPersistenceServiceFactory">
<field name="isTransactionEnabled"><false/></field>
</bean>
</factory>
</service>
<service name="tx" factory="org.jbpm.tx.TxServiceFactory" />
<service name="message" factory="org.jbpm.msg.db.DbMessageServiceFactory" />
<service name="scheduler" factory="org.jbpm.scheduler.db.DbSchedulerServiceFactory" />
<service name="logging" factory="org.jbpm.logging.db.DbLoggingServiceFactory" />
<service name="authentication"
factory="org.jbpm.security.authentication.DefaultAuthenticationServiceFactory" />
</jbpm-context>
</jbpm-configuration>The most important thing to notice here is that jBPM transaction control is disabled. Seam or EJB3 should control the JTA transactions.
There is not yet any well-defined packaging format for jBPM configuration and process/pageflow definition files. In the Seam examples we've decided to simply package all these files into the root of the EAR. In future, we will probably design some other standard packaging format. So the EAR looks something like this:
my-application.ear/
jboss-seam.jar
lib/
jboss-el.jar
jbpm-3.1.jar
META-INF/
MANIFEST.MF
application.xml
my-application.war/
META-INF/
MANIFEST.MF
WEB-INF/
web.xml
components.xml
faces-config.xml
lib/
jsf-facelets.jar
jboss-seam-ui.jar
login.jsp
register.jsp
...
my-application.jar/
META-INF/
MANIFEST.MF
persistence.xml
seam.properties
org/
jboss/
myapplication/
User.class
Login.class
LoginBean.class
Register.class
RegisterBean.class
...
jbpm.cfg.xml
hibernate.cfg.xml
createDocument.jpdl.xml
editDocument.jpdl.xml
approveDocument.jpdl.xml
documentLifecycle.jpdl.xmlTo run a Seam application as a portlet, you'll need to provide certain portlet metadata (portlet.xml, etc) in addition to the usual Java EE metadata. See the examples/portal directory for an example of the booking demo preconfigured to run on JBoss Portal.
It is very important that the timeout for Stateful Session Beans is set higher than the timeout for HTTP Sessions, otherwise SFSB's may time out before the user's HTTP session has ended. JBoss Application Server has a default session bean timeout of 30 minutes, which is configured in server/default/conf/standardjboss.xml (replace default with your own configuration).
The default SFSB timeout can be adjusted by modifying the value of max-bean-life in the LRUStatefulContextCachePolicy cache configuration:
<container-cache-conf>
<cache-policy>org.jboss.ejb.plugins.LRUStatefulContextCachePolicy</cache-policy>
<cache-policy-conf>
<min-capacity>50</min-capacity>
<max-capacity>1000000</max-capacity>
<remover-period>1800</remover-period>
<!-- SFSB timeout in seconds; 1800 seconds == 30 minutes -->
<max-bean-life>1800</max-bean-life>
<overager-period>300</overager-period>
<max-bean-age>600</max-bean-age>
<resizer-period>400</resizer-period>
<max-cache-miss-period>60</max-cache-miss-period>
<min-cache-miss-period>1</min-cache-miss-period>
<cache-load-factor>0.75</cache-load-factor>
</cache-policy-conf>
</container-cache-conf>The default HTTP session timeout can be modified in server/default/deploy/jbossweb-tomcat55.sar/conf/web.xml for JBoss 4.0.x, or in server/default/deploy/jboss-web.deployer/conf/web.xml for JBoss 4.2.x. The following entry in this file controls the default session timeout for all web applications:
<session-config>
<!-- HTTP Session timeout, in minutes -->
<session-timeout>30</session-timeout>
</session-config>To override this value for your own application, simply include this entry in your application's own web.xml.