Adding a JSF view Scope to Spring scope support

 

Here is a new Spring scope for JSF. It is just a prototype but it works. It will get added to Crank unless/until they add it to Spring.

Spring allows you to create a custom scope (scope as in singleton, prototype, session, etc).

See
http://static.springframework.org/spring/docs/2.5.x/api/org/springframework/beans/factory/config/Scope.html

And
(See section 3.4.5.1 in the Spring reference for more detail)
http://static.springframework.org/spring/docs/2.5.x/reference/beans.html#beans-factory-scopes

Along those lines, I have been meaning to create a JSF View scope for a while. I thought it would be pretty easy and it was. I had a working version in about 15 to 20 minutes. One wonders why they don't ship with such a beast (I will include it in Crank for now).

package org.crank.config.spring.support;    import java.util.HashMap;  import java.util.Map;    import javax.faces.context.FacesContext;    import org.springframework.beans.factory.ObjectFactory;  import org.springframework.beans.factory.config.Scope;    public class ViewScope implements Scope {     public final String VIEW_SCOPE_KEY = "CRANK_VIEW_SCOPE";      public Object get(String name, ObjectFactory objectFactory) {        if (FacesContext.getCurrentInstance().getViewRoot() != null) {     Map<String, Object> viewScope = extractViewScope();          if (viewScope.get(name) == null) {      Object object = objectFactory.getObject();      viewScope.put(name, object);      return object;     } else {      return viewScope.get(name);     }    } else {     System.out.println("################ : GET VIEW ROOT NOT FOUND");     return null;    }       }     @SuppressWarnings("unchecked")   private Map<String, Object> extractViewScope() {    Map<String, Object> attributes = FacesContext.getCurrentInstance().getViewRoot().getAttributes();        Map<String, Object> viewScope = null;        if (attributes.get(VIEW_SCOPE_KEY)==null) {     viewScope = new HashMap<String, Object>();     attributes.put(VIEW_SCOPE_KEY, viewScope);    } else {     viewScope = (Map<String, Object>) attributes.get(VIEW_SCOPE_KEY);    }    return viewScope;   }     public String getConversationId() {    return null;   }     public void registerDestructionCallback(String name, Runnable callback) {    System.out.println("#####################: We don't support destruction callbacks at this time");   }     public Object remove(String name) {    if (FacesContext.getCurrentInstance().getViewRoot() != null) {     Map<String, Object> viewScope = extractViewScope();     return viewScope.remove(name);    } else {     System.out.println("################ : REMOVE VIEW ROOT NOT FOUND");     return null;    }   }    }

 

With the above (which will be cleaned up) supports a view scope so now I can associate objects with the current view root, and when the view root changes, the objects go away.

@Bean(scope = DefaultScopes.SESSION)   public JsfCrudAdapter empRecordCrud() {

So now instead of the above... which stays around for the whole session, I can use:

@Bean(scope = "view")   public JsfCrudAdapter empRecordCrud() {