Custom scopes in CDI 1.0 and Spring 3.1

This blog post describes in short how to implement custom scopes in CDI using Weld 1.1 and Spring 3.1. To get basic information on scoping see the Spring reference or the Weld reference respectively.

Custom scopes in Spring

In Spring you have to implement your custom scope using the Scope interface. I have implemented a custom scope as a copy of request scope for illustration:

package com.mycompany.springapp.scope;
 
import org.springframework.beans.factory.config.Scope;
import org.springframework.web.context.request.AbstractRequestAttributesScope;
import org.springframework.web.context.request.RequestAttributes;
 
public class MyCustomScope extends AbstractRequestAttributesScope implements Scope {
 
 @Override
 protected int getScope() {
  return RequestAttributes.SCOPE_REQUEST;
 }
 
 /**
  * There is no conversation id concept for a request, so this method
  * returns <code>null</code>.
  */
 public String getConversationId() {
  return null;
 }
 
}

<beans>
 <bean class="org.springframework.beans.factory.config.CustomScopeConfigurer">
  <property name="scopes">
   <map>
    <entry key="custom">
     <bean class="com.mycompany.springapp.scope.MyCustomScope">
    </bean></entry>
   </map>
  </property>
 </bean>
</beans>

package com.mycompany.springapp.scope;
 
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;
 
@Component
@Scope("custom")
public class MyCustomScopedService {
 
}

package com.mycompany.jeeapp.scope.extension;
 
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
 
import javax.enterprise.context.NormalScope;
 
@Retention(java.lang.annotation.RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE, ElementType.METHOD})
@NormalScope
public @interface CustomScoped {
 
}

	
package com.mycompany.jeeapp.scope.extension;
 
import org.jboss.weld.context.http.HttpRequestContext;
import org.jboss.weld.context.http.HttpRequestContextImpl;
import java.lang.Class;
 
public class MyCustomScope extends HttpRequestContextImpl implements HttpRequestContext {
 
 public Class getScope() {
  return CustomScoped.class;
 }
  
}

@CustomScoped
public class MyCustomScopeService { ... }

package com.mycompany.jeeapp.scope.extension;
 
import javax.enterprise.event.Observes;
import javax.enterprise.inject.spi.AfterBeanDiscovery;
import javax.enterprise.inject.spi.BeanManager;
import javax.enterprise.inject.spi.Extension;
 
public class MyCustomScopeExtension implements Extension{
 
    public void afterBeanDiscovery(@Observes AfterBeanDiscovery event, BeanManager manager) {
        event.addContext(new MyCustomScope());
    }
}

From http://niklasschlimm.blogspot.com/2011/07/custom-scopes-in-cdi-10-and-spring-31.html