DWR

Hello,

I saw a bug when using DWR 2 in an OSGI environment. It occurs when trying to directly expose an OSGi service configured with Spring DM as a DWR remote service like below. I don't have the problem when defining an intermediate class between dwr and the OSGi service referenced using Spring DM.

<dwr:configuration>
    <dwr:create javascript="contactService" type="spring">
        <dwr:param name="beanName" value="contactService"/>
        <dwr:convert type="bean" class="com.manning.sdmia.directory.model.Contact"/>
    </dwr:create>
</dwr:configuration>

<dwr:controller id="dwrController" debug="true"/>

<osgi:reference id="contactService"
        interface="com.manning.sdmia.directory.service.ContactService">
</osgi:reference>

I have the following error when calling a method on the service with DWR:

10108 [http-8080-Processor4] WARN org.directwebremoting.impl.DefaultRemoter - Method execution failed:
java.lang.IllegalArgumentException: object is not an instance of declaring class
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.directwebremoting.impl.ExecuteAjaxFilter.doFilter(ExecuteAjaxFilter.java:36)
at org.directwebremoting.impl.DefaultRemoter$1.doFilter(DefaultRemoter.java:434)
at org.directwebremoting.impl.DefaultRemoter.execute(DefaultRemoter.java:437)
at org.directwebremoting.impl.DefaultRemoter.execute(DefaultRemoter.java:283)
        (...)

The problem comes from the BeanCreator class when determining type of the bean corresponding to the call. Spring DM provides a proxy in front of the OSGi service. The method afterPropertiesSet of the BeanCreator class sets this type with the implementation class instead of the proxy class...

To fix this bug, we can get this type directly using the proxy instance as shown below:

    public void afterPropertiesSet()
    {
        // make sure that either the bean or the beanId have been set correctly
        if (bean != null) {
            this.beanClass = bean.getClass();
        } else if (beanId != null) {
            //this.beanClass = beanFactory.getType(beanId);
            this.beanClass = beanFactory.getBean(beanId).getClass(); <----------------
        } else {
            throw new FatalBeanException(
                    "You should either set the bean property directly or set the beanId property");
        }

        // make sure to handle cglib proxies correctly
        if(AopUtils.isCglibProxyClass(this.beanClass)) {
            this.beanClass = this.beanClass.getSuperclass();
        }
    }

Thierry