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https://issues.apache.org/jira/browse/CAMEL-2026?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Claus Ibsen resolved CAMEL-2026.
--------------------------------
Resolution: Won't Fix
Fix Version/s: (was: Future)
2.8.0
Lets keep it as is
> Enable async request-reply by enhancing the CamelInvocationHandler so that it
> is serializable, so that camel-spring Proxies can be passed as callback
> objects
> -------------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: CAMEL-2026
> URL: https://issues.apache.org/jira/browse/CAMEL-2026
> Project: Camel
> Issue Type: Improvement
> Components: camel-core, camel-spring
> Affects Versions: 2.0.0
> Reporter: Scott Clasen
> Assignee: Claus Ibsen
> Fix For: 2.8.0
>
> Attachments: camel-2026.zip
>
>
> With minor alteration, the CamelInvocationHandler could be made serializable,
> and then camel-spring bean proxies could be passed as callback objects in
> method calls on other camel-spring proxies...enabling async request-reply via
> spring remoting.
> I have achieved this by Wrapping the CamelInvocationHandler, subclassing the
> CamelProxyFactoryBean, and by attaching a processor to routes that can
> recieve BeanInvocations that have a callback object. Integrated into the
> codebase, this could be much more straightforward, and not require a
> processor be attached.
> =================CamelInvocationHandlerWrapper
> {code}
> /**
> * Serializable wrapper for Camel/Spring remoting proxies.
> */
> public class CamelInvocationHandlerWrapper implements InvocationHandler,
> Serializable {
> /*
> Findbugs will complain that inner dosent get set at deserialization time.
> This is ok.
> You need to have a CamelRemotingProcessor in your inbound camel route that
> will reset the handler.
> */
> private transient CamelInvocationHandler inner;
> private String serviceUrl;
> private static final long serialVersionUID = 7635312279175935612L;
> /**
> * Create a CamelInvocationHandlerWrapper.
> *
> * @param handler the handler to use in this VM.
> * @param serviceUrl the serviceUrl to use to rebuild the
> CamelInvocationHandler if we are serialized and used in a different VM.
> */
> public CamelInvocationHandlerWrapper(CamelInvocationHandler handler,
> String serviceUrl) {
> this.inner = handler;
> this.serviceUrl = serviceUrl;
> }
> /**
> * {@inheritDoc}
> */
> public Object invoke(Object proxy, Method method, Object[] args) throws
> Throwable {
> if (method.getDeclaringClass().equals(Object.class)) {
> return method.invoke(this, args);
> } else {
> if (inner == null) {
> throw new IllegalStateException("The inner
> CamelInvocationHandler is null, perhaps there was no CamelRemotingProcessor
> on your inbound route???");
> } else {
> return inner.invoke(proxy, method, args);
> }
> }
> }
> /**
> * Package Private so the CamelRemotingProcessor can rewire when we are
> passed remotely.
> *
> * @param context the current camel context.
> * @throws Exception if we cant build an endpoint for the service url or
> create a producer.
> */
> void rebuildInvocationHandler(CamelContext context) throws Exception {
> Endpoint endpoint = CamelContextHelper.getMandatoryEndpoint(context,
> serviceUrl);
> Producer producer = endpoint.createProducer();
> producer.start();
> inner = new CamelInvocationHandler(endpoint, producer, new
> MethodInfoCache(endpoint.getCamelContext()));
> }
> void setServiceUrl(String serviceUrl) {
> this.serviceUrl = serviceUrl;
> }
> }
> {code}
> ================Proxy Factory
> {code}
> /**
> * ProxyFactory that wraps a camel proxy in a serializable form.
> */
> public class CamelProxyWrapperFactoryBean extends CamelProxyFactoryBean {
> /**
> * Override the CamelProxyFactoryBean to return a different proxy that
> uses a CamelInvocationHandlerWrapper.
> *
> * @return a Proxy backed by a CamelInvocationHandlerWrapper for the
> specified interface.
> * @throws Exception if we cant create the proxy.
> */
> @Override
> public Object getObject() throws Exception {
> Object proxy = super.getObject();
> CamelInvocationHandler handler = (CamelInvocationHandler)
> Proxy.getInvocationHandler(proxy);
> return Proxy.newProxyInstance(getObjectType().getClassLoader(), new
> Class[]{getObjectType()}, new CamelInvocationHandlerWrapper(handler,
> getServiceUrl()));
> }
> }
> {code}
> ========processor that "rewires" the transient CamelInvocationHandler by
> using the service url
> {code}
> public class CamelRemotingProcessor implements Processor {
> /**
> * Rebuild the CamelInvocationHandler if we were passed a Proxy that has
> a CamelInvocationHandlerWrapper as its handler.
> *
> * @param invocation the BeanInvocation whose args we check for the Proxy.
> * @param context the current Camel Context.
> * @throws Exception if something blows up.
> */
> public void rewireProxy(BeanInvocation invocation, CamelContext context)
> throws Exception {
> Object[] args = invocation.getArgs();
> if (args != null) {
> for (Object arg : args) {
> if (Proxy.isProxyClass(arg.getClass())) {
> InvocationHandler handler =
> Proxy.getInvocationHandler(arg);
> if (handler instanceof CamelInvocationHandlerWrapper) {
> CamelInvocationHandlerWrapper wrapper =
> (CamelInvocationHandlerWrapper) handler;
> wrapper.rebuildInvocationHandler(context);
> }
> }
> }
> }
> }
> /**
> * {@inheritDoc}
> */
> public void process(Exchange exchange) throws Exception {
> CamelContext context = exchange.getContext();
> BeanInvocation invocation =
> exchange.getIn().getBody(BeanInvocation.class);
> rewireProxy(invocation, context);
> }
> }
> {code}
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