Spring中的JSF View范围

Question

@ViewScoped Spring 3.0中是否有类似JSF的范围？我有一个使用JSF + Spring的应用程序，其中后备bean由Spring管理。我没有在Spring中找到像JSF wiew scope这样的范围。但是它对我没有用。

这是我对自定义Spring范围的尝试：

import java.util.Map;

import javax.faces.context.FacesContext;

import org.springframework.beans.factory.ObjectFactory;
import org.springframework.beans.factory.config.Scope;

/**
 * Implements the JSF View Scope for use by Spring. This class is registered as a Spring bean with the CustomScopeConfigurer.
*/
public class ViewScope implements Scope {

    public Object get(String name, ObjectFactory<?> objectFactory) {

        System.out.println("**************************************************");
        System.out.println("-------------------- Getting objects For View Scope ----------");
        System.out.println("**************************************************");
        if (FacesContext.getCurrentInstance().getViewRoot() != null) {
            Map<String, Object> viewMap = FacesContext.getCurrentInstance().getViewRoot().getViewMap();
            if (viewMap.containsKey(name)) {
                return viewMap.get(name);
            } else {
                Object object = objectFactory.getObject();
                viewMap.put(name, object);
                return object;
            }
        } else {
            return null;
        }
    }

    public Object remove(String name) {
        System.out.println("**************************************************");
        System.out.println("-------------------- View Scope object Removed ----------");
        System.out.println("**************************************************");

        if (FacesContext.getCurrentInstance().getViewRoot() != null) {
            return FacesContext.getCurrentInstance().getViewRoot().getViewMap().remove(name);
        } else {
            return null;
        }
    }

    public void registerDestructionCallback(String name, Runnable callback) {
        // Do nothing
    }

    public Object resolveContextualObject(String key) {         return null;
    }

    public String getConversationId() {
        return null;
    }

}

application-context.xml：

<bean class="org.springframework.beans.factory.config.CustomScopeConfigurer">
    <property name="scopes">
            <map>
                <entry key="view">
                    <bean class="com.delta.beans.ViewScope"/>
                </entry>
            </map>
        </property>
 </bean>

Answer 1

public class ViewScopeCallbackRegistrer implements ViewMapListener {

  @SuppressWarnings("unchecked")
  @Override
  public void processEvent(SystemEvent event) throws AbortProcessingException {
    if (event instanceof PostConstructViewMapEvent) {
      PostConstructViewMapEvent viewMapEvent = (PostConstructViewMapEvent) event;

      UIViewRoot viewRoot = (UIViewRoot) viewMapEvent.getComponent();

      viewRoot.getViewMap().put(
          ViewScope.VIEW_SCOPE_CALLBACKS,
          new HashMap<String, Runnable>()
      );

    } else if (event instanceof PreDestroyViewMapEvent) {
      PreDestroyViewMapEvent viewMapEvent = (PreDestroyViewMapEvent) event;

      UIViewRoot viewRoot = (UIViewRoot) viewMapEvent.getComponent();

      Map<String, Runnable> callbacks = (Map<String, Runnable>) viewRoot
          .getViewMap().get(ViewScope.VIEW_SCOPE_CALLBACKS);

      if (callbacks != null) {
        for (Runnable c : callbacks.values()) {
          c.run();
        }
        callbacks.clear();
      }
    }
  }

  @Override
  public boolean isListenerForSource(Object source) {
    return source instanceof UIViewRoot;
  }
}