package net.sourceforge.stripes.integration.spring;

import net.sourceforge.stripes.action.*;
import net.sourceforge.stripes.controller.*;
import net.sourceforge.stripes.util.*;
import org.springframework.beans.factory.config.*;
import org.springframework.context.*;
import org.springframework.util.*;
import org.springframework.web.context.support.*;

import javax.servlet.*;

/**
 * <p>An {@link net.sourceforge.stripes.controller.Interceptor} that uses a Spring context to inject
 * Spring beans into newly created ActionBeans immediately following ActionBeanResolution.
 * Dependency injection is performed by Spring's native autowiring bean factory, so all of the
 * standard Spring dependency injection annotations are supported, including &#64;Autowired,
 * &#64;Resource, and &#64;Qualifier.  Fields and/or methods may be annotated with these annotations.
 * <p/>
 * <p>Example:</p>
 * <pre>
 * public class SomeActionBean implements ActionBean
 * {
 *     // Autowire by type injection on a field (no setter is necessary)
 *     &#64;Autowired private UserService userService;
 *
 *     private TravelService travelService;
 *
 *     // Autowire by name injection via a setter method
 *     &#64;Resource
 *     public void setTravelService(TripService travelService) { this.travelService = travelService; }
 *
 *     //...
 * }
 * </pre>
 * <p>To configure the SpringInterceptor for use you will need to add the following to your
 * web.xml (assuming no other interceptors are yet configured):</p>
 * <p/>
 * <pre>
 * &lt;init-param&gt;
 *     &lt;param-name&gt;Interceptor.Classes&lt;/param-name&gt;
 *     &lt;param-value&gt;
 *         net.sourceforge.stripes.integration.spring.Spring25Interceptor
 *     &lt;/param-value&gt;
 * &lt;/init-param&gt;
 * </pre>
 * <p/>
 * <p>If one or more interceptors are already configured in your web.xml simply separate the
 * fully qualified names of the interceptors with commas (additional whitespace is ok).</p>
 *
 * <p>This interceptor requires Spring 2.5 or newer.</p>
 *
 * @author Christian Nelson
 * @see org.springframework.beans.factory.config.AutowireCapableBeanFactory
 * @see org.springframework.beans.factory.annotation.Autowired
 * @see org.springframework.beans.factory.annotation.Qualifier
 * @see javax.annotation.Resource
 * @since Stripes 1.5
 */
@Intercepts(LifecycleStage.ActionBeanResolution)
public class Spring25Interceptor implements Interceptor
{
    private static final Log log = Log.getInstance(Spring25Interceptor.class);

    /**
     * Allows ActionBean resolution to proceed and then once the ActionBean has been located performs Spring dependency injection.
     *
     * @param context the current execution context
     * @return the Resolution produced by calling context.proceed()
     * @throws Exception if the Spring binding process produced unrecoverable errors
     */
    public Resolution intercept(ExecutionContext context) throws Exception
    {
        Resolution resolution = context.proceed();
        log.debug("Running Spring dependency injection for instance of ", context.getActionBean().getClass().getSimpleName());
        ServletContext servletContext = StripesFilter.getConfiguration().getServletContext();
        ApplicationContext applicationContext = WebApplicationContextUtils.getWebApplicationContext(servletContext);
        AutowireCapableBeanFactory beanFactory = applicationContext.getAutowireCapableBeanFactory();
        beanFactory.autowireBeanProperties(context.getActionBean(), AutowireCapableBeanFactory.AUTOWIRE_NO, false);
        beanFactory.initializeBean(context.getActionBean(), StringUtils.uncapitalize(context.getActionBean().getClass().getSimpleName()));
        return resolution;
    }
}