26.4. Seam-scoped Spring beans

With the Seam integration package, you can also use Seam's contexts as Spring 2.0-style custom scopes, which lets you declare any Spring bean in any Seam context. However, because Spring's component model was not built to support statefulness, this feature should be used with care. In particular, there are problems with clustering session- or conversation-scoped Spring beans, and care must be taken when injecting a bean or component from a wider scope into a bean of narrower scope.

Specify <seam:configure-scopes/> in a Spring bean factory configuration to make all Seam scopes available to Spring beans as custom scopes. To associate a Spring bean with a particular Seam scope, specify the desired scope in the scope attribute of the bean definition.

<!-- Only needs to be specified once per bean factory-->
<seam:configure-scopes/>

...

<bean id="someSpringBean" class="SomeSpringBeanClass" 
      scope="seam.CONVERSATION"/>

You can change the scope name's prefix by specifying the prefix attribute in the configure-scopes definition. (The default prefix is seam..)

By default, a Spring component instance that is registered this way is not created automatically when referenced with @In. To automatically create an instance, you must either specify @In(create=true) at the injection point (to auto-create a specific bean), or use the default-auto-create attribute of configure-scopes to auto-create all Seam-scoped Spring beans.

The latter approach lets you inject Seam-scoped Spring beans into other Spring beans without using <seam:instance/>. However, you must be careful to maintain scope impedance. Normally, you would specify <aop:scoped-proxy/> in the bean definition, but Seam-scoped Spring beans are not compatible with <aop:scoped-proxy/>. Therefore, to inject a Seam-scoped Spring bean into a singleton, use <seam:instance/>:

<bean id="someSpringBean" class="SomeSpringBeanClass" scope="seam.CONVERSATION"/>

...

<bean id="someSingleton">
  <property name="someSeamScopedSpringBean">
    <seam:instance name="someSpringBean" proxy="true"/>
  </property>
</bean>