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package com.sun.jersey.server.impl.ejb;

import com.sun.jersey.api.model.AbstractResource;
import com.sun.jersey.api.model.AbstractResourceMethod;
import com.sun.jersey.spi.container.JavaMethodInvoker;
import com.sun.jersey.spi.container.ResourceMethodCustomInvokerDispatchFactory;
import com.sun.jersey.spi.container.ResourceMethodDispatchProvider;
import com.sun.jersey.spi.dispatch.RequestDispatcher;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.ejb.Local;
import javax.ejb.Remote;
import javax.ejb.Stateful;
import javax.ejb.Stateless;

import javax.ws.rs.core.Context;

/**
 *
 * @author japod
 */
public class EJBRequestDispatcherProvider implements ResourceMethodDispatchProvider {

    @Context
    ResourceMethodCustomInvokerDispatchFactory rdFactory;

    @Override
    public RequestDispatcher create(AbstractResourceMethod abstractResourceMethod) {

        final AbstractResource declaringResource = abstractResourceMethod.getDeclaringResource();

        if (isSessionBean(declaringResource)) {

            final Class<?> resourceClass = declaringResource.getResourceClass();
            final Method javaMethod = abstractResourceMethod.getMethod();

            for (Class iFace: remoteAndLocalIfaces(resourceClass)) {
                    try {
                        final Method iFaceMethod = iFace.getDeclaredMethod(javaMethod.getName(), javaMethod.getParameterTypes());
                        if (iFaceMethod != null) {
                            return createDispatcher(abstractResourceMethod, iFaceMethod);
                        }
                    } catch (NoSuchMethodException ex) {
                    } catch (SecurityException ex) {
                        Logger.getLogger(EJBRequestDispatcherProvider.class.getName()).log(Level.SEVERE, null, ex);
                    }
            }
        }

        return null;
    }

    private List<Class> remoteAndLocalIfaces(final Class<?> resourceClass) {
        final List<Class> allLocalOrRemoteIfaces = new LinkedList<Class>();
        if (resourceClass.isAnnotationPresent(Remote.class)) {
            allLocalOrRemoteIfaces.addAll(Arrays.asList(resourceClass.getAnnotation(Remote.class).value()));
        }
        if (resourceClass.isAnnotationPresent(Local.class)) {
            allLocalOrRemoteIfaces.addAll(Arrays.asList(resourceClass.getAnnotation(Local.class).value()));
        }
        for (Class<?> i : resourceClass.getInterfaces()) {
            if (i.isAnnotationPresent(Remote.class) || i.isAnnotationPresent(Local.class)) {
                allLocalOrRemoteIfaces.add(i);
            }
        }
        return allLocalOrRemoteIfaces;
    }

    private RequestDispatcher createDispatcher(AbstractResourceMethod abstractResourceMethod, final Method iFaceMethod) {
        return rdFactory.getDispatcher(abstractResourceMethod, new JavaMethodInvoker() {

            @Override
            public Object invoke(Method m, Object o, Object... parameters) throws InvocationTargetException, IllegalAccessException {
                return iFaceMethod.invoke(o, parameters);
            }
        });
    }

    private boolean isSessionBean(AbstractResource ar) {
        return ar.isAnnotationPresent(Stateless.class) || ar.isAnnotationPresent(Stateful.class);
    }
}
