com.alibaba.dubbo.rpc.Exporter Java Examples

public <T> Exporter<T> export( Invoker<T> invoker ) throws RpcException {

        // 只能使用 thrift codec
        URL url = invoker.getUrl().addParameter(Constants.CODEC_KEY, ThriftCodec.NAME);
        // find server.
        String key = url.getAddress();
        //client 也可以暴露一个只有server可以调用的服务。
        boolean isServer = url.getParameter(Constants.IS_SERVER_KEY,true);
        if (isServer && ! serverMap.containsKey(key)) {
            serverMap.put(key, getServer(url));
        }
        // export service.
        key = serviceKey(url);
        DubboExporter<T> exporter = new DubboExporter<T>(invoker, key, exporterMap);
        exporterMap.put(key, exporter);

        return exporter;
    }
 

public <T> Exporter<T> export( Invoker<T> invoker ) throws RpcException {

        // 只能使用 thrift codec
        URL url = invoker.getUrl().addParameter(Constants.CODEC_KEY, ThriftCodec.NAME);
        // find server.
        String key = url.getAddress();
        //client 也可以暴露一个只有server可以调用的服务。
        boolean isServer = url.getParameter(Constants.IS_SERVER_KEY,true);
        if (isServer && ! serverMap.containsKey(key)) {
            serverMap.put(key, getServer(url));
        }
        // export service.
        key = serviceKey(url);
        DubboExporter<T> exporter = new DubboExporter<T>(invoker, key, exporterMap);
        exporterMap.put(key, exporter);

        return exporter;
    }
 

@Test
public void testOverload() {
    HessianServiceImpl server = new HessianServiceImpl();
    Assert.assertFalse(server.isCalled());
    ProxyFactory proxyFactory = ExtensionLoader.getExtensionLoader(ProxyFactory.class).getAdaptiveExtension();
    Protocol protocol = ExtensionLoader.getExtensionLoader(Protocol.class).getAdaptiveExtension();
    URL url = URL.valueOf("hessian://127.0.0.1:5342/" + HessianService.class.getName() + "?version=1.0.0&hessian.overload.method=true&hessian2.request=false");
    Exporter<HessianService> exporter = protocol.export(proxyFactory.getInvoker(server, HessianService.class, url));
    Invoker<HessianService> invoker = protocol.refer(HessianService.class, url);
    HessianService client = proxyFactory.getProxy(invoker);
    String result = client.sayHello("haha");
    Assert.assertEquals("Hello, haha", result);
    result = client.sayHello("haha", 1);
    Assert.assertEquals("Hello, haha. ", result);
    invoker.destroy();
    exporter.unexport();
}
 

@Test
public void testDelayFixedTime() throws Exception {
    SimpleRegistryService registryService = new SimpleRegistryService();
    Exporter<RegistryService> exporter = SimpleRegistryExporter.export(4548, registryService);
    ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext(ConfigTest.class.getPackage().getName().replace('.', '/') + "/delay-fixed-time.xml");
    ctx.start();
    try {
        List<URL> urls = registryService.getRegistered().get("com.alibaba.dubbo.config.spring.api.DemoService");
        assertNull(urls);
        int i = 0;
        while ((i ++) < 60 && urls == null) {
            urls = registryService.getRegistered().get("com.alibaba.dubbo.config.spring.api.DemoService");
            Thread.sleep(10);
        }
        assertNotNull(urls);
        assertEquals(1, urls.size());
        assertEquals("dubbo://" + NetUtils.getLocalHost() + ":20883/com.alibaba.dubbo.config.spring.api.DemoService", urls.get(0).toIdentityString());
    } finally {
        ctx.stop();
        ctx.close();
        exporter.unexport();
    }
}
 

@Test
public void testMultiProtocolRegister() {
    SimpleRegistryService registryService = new SimpleRegistryService();
    Exporter<RegistryService> exporter = SimpleRegistryExporter.export(4547, registryService);
    ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext(ConfigTest.class.getPackage().getName().replace('.', '/') + "/multi-protocol-register.xml");
    ctx.start();
    try {
        List<URL> urls = registryService.getRegistered().get("com.alibaba.dubbo.config.spring.api.DemoService");
        assertNotNull(urls);
        assertEquals(1, urls.size());
        assertEquals("dubbo://" + NetUtils.getLocalHost() + ":20824/com.alibaba.dubbo.config.spring.api.DemoService", urls.get(0).toIdentityString());
    } finally {
        ctx.stop();
        ctx.close();
        exporter.unexport();
    }
}
 

@Test
public void testDelayOnInitialized() throws Exception {
    SimpleRegistryService registryService = new SimpleRegistryService();
    Exporter<RegistryService> exporter = SimpleRegistryExporter.export(4548, registryService);
    ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext(ConfigTest.class.getPackage().getName().replace('.', '/') + "/delay-on-initialized.xml");
    //ctx.start();
    try {
        List<URL> urls = registryService.getRegistered().get("com.alibaba.dubbo.config.spring.api.DemoService");
        assertNotNull(urls);
        assertEquals(1, urls.size());
        assertEquals("dubbo://" + NetUtils.getLocalHost() + ":20883/com.alibaba.dubbo.config.spring.api.DemoService", urls.get(0).toIdentityString());
    } finally {
        ctx.stop();
        ctx.close();
        exporter.unexport();
    }
}
 

@Test
public void testGenericInvokeWithBean() {
    HessianServiceImpl server = new HessianServiceImpl();
    Assert.assertFalse(server.isCalled());
    ProxyFactory proxyFactory = ExtensionLoader.getExtensionLoader(ProxyFactory.class).getAdaptiveExtension();
    Protocol protocol = ExtensionLoader.getExtensionLoader(Protocol.class).getAdaptiveExtension();
    URL url = URL.valueOf("hessian://127.0.0.1:5342/" + HessianService.class.getName() + "?version=1.0.0&generic=bean");
    Exporter<HessianService> exporter = protocol.export(proxyFactory.getInvoker(server, HessianService.class, url));
    Invoker<GenericService> invoker = protocol.refer(GenericService.class, url);
    GenericService client = proxyFactory.getProxy(invoker);

    JavaBeanDescriptor javaBeanDescriptor = JavaBeanSerializeUtil.serialize("haha");

    Object result = client.$invoke("sayHello", new String[]{"java.lang.String"}, new Object[]{javaBeanDescriptor});
    Assert.assertTrue(server.isCalled());
    Assert.assertEquals("Hello, haha", JavaBeanSerializeUtil.deserialize((JavaBeanDescriptor) result));
    invoker.destroy();
    exporter.unexport();
}
 

@Test
public void testGenericInvokeWithRpcContext() {
    RpcContext.getContext().setAttachment("myContext", "123");

    HessianServiceImpl server = new HessianServiceImpl();
    ProxyFactory proxyFactory = ExtensionLoader.getExtensionLoader(ProxyFactory.class).getAdaptiveExtension();
    Protocol protocol = ExtensionLoader.getExtensionLoader(Protocol.class).getAdaptiveExtension();
    URL url = URL.valueOf("hessian://127.0.0.1:5342/" + HessianService.class.getName() + "?version=1.0.0");
    Exporter<HessianService> exporter = protocol.export(proxyFactory.getInvoker(server, HessianService.class, url));
    Invoker<GenericService> invoker = protocol.refer(GenericService.class, url);
    GenericService client = proxyFactory.getProxy(invoker, true);
    String result = (String) client.$invoke("context", new String[]{"java.lang.String"}, new Object[]{"haha"});
    Assert.assertEquals("Hello, haha context, 123", result);
    invoker.destroy();
    exporter.unexport();
}
 

public synchronized void unexport() {
    if (! exported) {
        return;
    }
    if (unexported) {
        return;
    }
	if (exporters != null && exporters.size() > 0) {
		for (Exporter<?> exporter : exporters) {
			try {
                exporter.unexport();
            } catch (Throwable t) {
                logger.warn("unexpected err when unexport" + exporter, t);
            }
		}
		exporters.clear();
	}
    unexported = true;
}
 

@Test
public void testHessianProtocol() {
    HessianServiceImpl server = new HessianServiceImpl();
    Assert.assertFalse(server.isCalled());
    ProxyFactory proxyFactory = ExtensionLoader.getExtensionLoader(ProxyFactory.class).getAdaptiveExtension();
    Protocol protocol = ExtensionLoader.getExtensionLoader(Protocol.class).getAdaptiveExtension();
    URL url = URL.valueOf("hessian://127.0.0.1:5342/" + HessianService.class.getName() + "?version=1.0.0&hessian.overload.method=true");
    Exporter<HessianService> exporter = protocol.export(proxyFactory.getInvoker(server, HessianService.class, url));
    Invoker<HessianService> invoker = protocol.refer(HessianService.class, url);
    HessianService client = proxyFactory.getProxy(invoker);
    String result = client.sayHello("haha");
    Assert.assertTrue(server.isCalled());
    Assert.assertEquals("Hello, haha", result);
    invoker.destroy();
    exporter.unexport();
}
 

@SuppressWarnings("unchecked")
private <T> ExporterChangeableWrapper<T>  doLocalExport(final Invoker<T> originInvoker){
    String key = getCacheKey(originInvoker);
    ExporterChangeableWrapper<T> exporter = (ExporterChangeableWrapper<T>) bounds.get(key);
    if (exporter == null) {
        synchronized (bounds) {
            exporter = (ExporterChangeableWrapper<T>) bounds.get(key);
            if (exporter == null) {
                final Invoker<?> invokerDelegete = new InvokerDelegete<T>(originInvoker, getProviderUrl(originInvoker));
                exporter = new ExporterChangeableWrapper<T>((Exporter<T>)protocol.export(invokerDelegete), originInvoker);
                bounds.put(key, exporter);
            }
        }
    }
    return (ExporterChangeableWrapper<T>) exporter;
}
 

@SuppressWarnings("unchecked")
public <T> Exporter<T> export(final Invoker<T> invoker) throws RpcException {
       final String uri = serviceKey(invoker.getUrl());
       Exporter<T> exporter = (Exporter<T>) exporterMap.get(uri);
       if (exporter != null) {
       	return exporter;
       }
       final Runnable runnable = doExport(proxyFactory.getProxy(invoker), invoker.getInterface(), invoker.getUrl());
       exporter = new AbstractExporter<T>(invoker) {
           public void unexport() {
               super.unexport();
               exporterMap.remove(uri);
               if (runnable != null) {
                   try {
                       runnable.run();
                   } catch (Throwable t) {
                       logger.warn(t.getMessage(), t);
                   }
               }
           }
       };
       exporterMap.put(uri, exporter);
       return exporter;
   }
 

@Test
public void testDelayOnInitialized() throws Exception {
    SimpleRegistryService registryService = new SimpleRegistryService();
    Exporter<RegistryService> exporter = SimpleRegistryExporter.export(4548, registryService);
    ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext(ConfigTest.class.getPackage().getName().replace('.', '/') + "/delay-on-initialized.xml");
    //ctx.start();
    try {
        List<URL> urls = registryService.getRegistered().get("com.alibaba.dubbo.config.spring.api.DemoService");
        assertNotNull(urls);
        assertEquals(1, urls.size());
        assertEquals("dubbo://" + NetUtils.getLocalHost() + ":20883/com.alibaba.dubbo.config.spring.api.DemoService", urls.get(0).toIdentityString());
    } finally {
        ctx.stop();
        ctx.close();
        exporter.unexport();
    }
}
 

@Test
public void testAnnotation() {
    SimpleRegistryService registryService = new SimpleRegistryService();
    Exporter<RegistryService> exporter = SimpleRegistryExporter.export(4548, registryService);
    try {
        ClassPathXmlApplicationContext providerContext = new ClassPathXmlApplicationContext(ConfigTest.class.getPackage().getName().replace('.', '/') + "/annotation-provider.xml");
        providerContext.start();
        try {
            ClassPathXmlApplicationContext consumerContext = new ClassPathXmlApplicationContext(ConfigTest.class.getPackage().getName().replace('.', '/') + "/annotation-consumer.xml");
            consumerContext.start();
            try {
                AnnotationAction annotationAction = (AnnotationAction) consumerContext.getBean("annotationAction");
                String hello = annotationAction.doSayName("hello");
                assertEquals("annotation:hello", hello);
            } finally {
                consumerContext.stop();
                consumerContext.close();
            }
        } finally {
            providerContext.stop();
            providerContext.close();
        }
    } finally {
        exporter.unexport();
    }
}
 

@Test
public void testHttpClient() {
    HessianServiceImpl server = new HessianServiceImpl();
    Assert.assertFalse(server.isCalled());
    ProxyFactory proxyFactory = ExtensionLoader.getExtensionLoader(ProxyFactory.class).getAdaptiveExtension();
    Protocol protocol = ExtensionLoader.getExtensionLoader(Protocol.class).getAdaptiveExtension();
    URL url = URL.valueOf("hessian://127.0.0.1:5342/" + HessianService.class.getName() + "?version=1.0.0&client=httpclient");
    Exporter<HessianService> exporter = protocol.export(proxyFactory.getInvoker(server, HessianService.class, url));
    Invoker<HessianService> invoker = protocol.refer(HessianService.class, url);
    HessianService client = proxyFactory.getProxy(invoker);
    String result = client.sayHello("haha");
    Assert.assertTrue(server.isCalled());
    Assert.assertEquals("Hello, haha", result);
    invoker.destroy();
    exporter.unexport();
}
 

@Test
public void testCustomException() {
    HessianServiceImpl server = new HessianServiceImpl();
    ProxyFactory proxyFactory = ExtensionLoader.getExtensionLoader(ProxyFactory.class).getAdaptiveExtension();
    Protocol protocol = ExtensionLoader.getExtensionLoader(Protocol.class).getAdaptiveExtension();
    URL url = URL.valueOf("hessian://127.0.0.1:5342/" + HessianService.class.getName() + "?version=1.0.0");
    Exporter<HessianService> exporter = protocol.export(proxyFactory.getInvoker(server, HessianService.class, url));
    Invoker<HessianService> invoker = protocol.refer(HessianService.class, url);
    HessianService client = proxyFactory.getProxy(invoker);
    try {
        client.customException();
        fail();
    } catch (MyException expected) {
    }
    invoker.destroy();
    exporter.unexport();
}
 

@Test
public void testHessianProtocol() {
    HessianServiceImpl server = new HessianServiceImpl();
    Assert.assertFalse(server.isCalled());
    ProxyFactory proxyFactory = ExtensionLoader.getExtensionLoader(ProxyFactory.class).getAdaptiveExtension();
    Protocol protocol = ExtensionLoader.getExtensionLoader(Protocol.class).getAdaptiveExtension();
    URL url = URL.valueOf("hessian://127.0.0.1:5342/" + HessianService.class.getName() + "?version=1.0.0");
    Exporter<HessianService> exporter = protocol.export(proxyFactory.getInvoker(server, HessianService.class, url));
    Invoker<HessianService> invoker = protocol.refer(HessianService.class, url);
    HessianService client = proxyFactory.getProxy(invoker);
    String result = client.sayHello("haha");
    Assert.assertTrue(server.isCalled());
    Assert.assertEquals("Hello, haha", result);
    invoker.destroy();
    exporter.unexport();
}
 

@Test
public void testDelayFixedTime() throws Exception {
    SimpleRegistryService registryService = new SimpleRegistryService();
    Exporter<RegistryService> exporter = SimpleRegistryExporter.export(4548, registryService);
    ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext(ConfigTest.class.getPackage().getName().replace('.', '/') + "/delay-fixed-time.xml");
    ctx.start();
    try {
        List<URL> urls = registryService.getRegistered().get("com.alibaba.dubbo.config.spring.api.DemoService");
        assertNull(urls);
        int i = 0;
        while ((i ++) < 60 && urls == null) {
            urls = registryService.getRegistered().get("com.alibaba.dubbo.config.spring.api.DemoService");
            Thread.sleep(10);
        }
        assertNotNull(urls);
        assertEquals(1, urls.size());
        assertEquals("dubbo://" + NetUtils.getLocalHost() + ":20883/com.alibaba.dubbo.config.spring.api.DemoService", urls.get(0).toIdentityString());
    } finally {
        ctx.stop();
        ctx.close();
        exporter.unexport();
    }
}
 

public <T> Exporter<T> export( Invoker<T> invoker ) throws RpcException {

        // 只能使用 thrift codec
        URL url = invoker.getUrl().addParameter(Constants.CODEC_KEY, ThriftCodec.NAME);
        // find server.
        String key = url.getAddress();
        //client 也可以暴露一个只有server可以调用的服务。
        boolean isServer = url.getParameter(Constants.IS_SERVER_KEY,true);
        if (isServer && ! serverMap.containsKey(key)) {
            serverMap.put(key, getServer(url));
        }
        // export service.
        key = serviceKey(url);
        DubboExporter<T> exporter = new DubboExporter<T>(invoker, key, exporterMap);
        exporterMap.put(key, exporter);

        return exporter;
    }
 

public <T> Exporter<T> export( Invoker<T> invoker ) throws RpcException {

        // 只能使用 thrift codec
        URL url = invoker.getUrl().addParameter(Constants.CODEC_KEY, ThriftCodec.NAME);
        // find server.
        String key = url.getAddress();
        //client 也可以暴露一个只有server可以调用的服务。
        boolean isServer = url.getParameter(Constants.IS_SERVER_KEY,true);
        if (isServer && ! serverMap.containsKey(key)) {
            serverMap.put(key, getServer(url));
        }
        // export service.
        key = serviceKey(url);
        DubboExporter<T> exporter = new DubboExporter<T>(invoker, key, exporterMap);
        exporterMap.put(key, exporter);

        return exporter;
    }
 

@Test
public void testNotifyOverride() throws Exception{
    URL newRegistryUrl = registryUrl.addParameter(Constants.EXPORT_KEY, serviceUrl);
    Invoker<RegistryProtocolTest> invoker = new MockInvoker<RegistryProtocolTest>(RegistryProtocolTest.class, newRegistryUrl);
    Exporter<?> exporter = protocol.export(invoker);
    RegistryProtocol rprotocol = RegistryProtocol.getRegistryProtocol();
    NotifyListener listener = getListener(rprotocol);
    List<URL> urls = new ArrayList<URL>();
    urls.add(URL.valueOf("override://0.0.0.0/?timeout=1000"));
    urls.add(URL.valueOf("override://0.0.0.0/"+ service + "?timeout=100"));
    urls.add(URL.valueOf("override://0.0.0.0/"+ service + "?x=y"));
    listener.notify(urls);
    
    assertEquals(true, exporter.getInvoker().isAvailable());
    assertEquals("100", exporter.getInvoker().getUrl().getParameter("timeout"));
    assertEquals("y", exporter.getInvoker().getUrl().getParameter("x"));
    
    exporter.unexport();
    assertEquals(false, exporter.getInvoker().isAvailable());
    destroyRegistryProtocol();
    
}
 

@SuppressWarnings({ "unchecked", "rawtypes" })
private void exportLocal(URL url) {
    if (!Constants.LOCAL_PROTOCOL.equalsIgnoreCase(url.getProtocol())) {
        URL local = URL.valueOf(url.toFullString())
                .setProtocol(Constants.LOCAL_PROTOCOL)
                .setHost(NetUtils.LOCALHOST)
                .setPort(0);

        // modified by lishen
        ServiceClassHolder.getInstance().pushServiceClass(getServiceClass(ref));

        Exporter<?> exporter = protocol.export(
                proxyFactory.getInvoker(ref, (Class) interfaceClass, local));
        exporters.add(exporter);
        logger.info("Export dubbo service " + interfaceClass.getName() +" to local registry");
    }
}
 

static Exporter<?> getExporter(Map<String, Exporter<?>> map, URL key) {
    Exporter<?> result = null;

    if (!key.getServiceKey().contains("*")) {
        result = map.get(key.getServiceKey());
    } else {
        if (map != null && !map.isEmpty()) {
            for (Exporter<?> exporter : map.values()) {
                if (UrlUtils.isServiceKeyMatch(key, exporter.getInvoker().getUrl())) {
                    result = exporter;
                    break;
                }
            }
        }
    }

    if (result == null) {
        return null;
    } else if (ProtocolUtils.isGeneric(
            result.getInvoker().getUrl().getParameter(Constants.GENERIC_KEY))) {
        return null;
    } else {
        return result;
    }
}
 

public ListenerExporterWrapper(Exporter<T> exporter, List<ExporterListener> listeners){
    if (exporter == null) {
        throw new IllegalArgumentException("exporter == null");
    }
    this.exporter = exporter;
    this.listeners = listeners;
    if (listeners != null && listeners.size() > 0) {
        RuntimeException exception = null;
        for (ExporterListener listener : listeners) {
            if (listener != null) {
                try {
                    listener.exported(this);
                } catch (RuntimeException t) {
                    logger.error(t.getMessage(), t);
                    exception = t;
                }
            }
        }
        if (exception != null) {
            throw exception;
        }
    }
}
 

private static Method findMethod(Exporter<?> exporter, String method, List<Object> args) {
    Invoker<?> invoker = exporter.getInvoker();
    Method[] methods = invoker.getInterface().getMethods();
    Method invokeMethod = null;
    for (Method m : methods) {
        if (m.getName().equals(method) && m.getParameterTypes().length == args.size()) {
            if (invokeMethod != null) { // 重载
                if (isMatch(invokeMethod.getParameterTypes(), args)) {
                    invokeMethod = m;
                    break;
                }
            } else {
                invokeMethod = m;
            }
            invoker = exporter.getInvoker();
        }
    }
    return invokeMethod;
}
 

@Test
public void test_normal_channel_close_wait_gracefully() throws Exception {

    URL url = URL.valueOf("dubbo://127.0.0.1:20883/hi?scope=true&lazy=false");
    Exporter<IDemoService> exporter = ProtocolUtils.export(new DemoServiceImpl(), IDemoService.class, url);
    Exporter<IDemoService> exporter0 = ProtocolUtils.export(new DemoServiceImpl0(), IDemoService.class, url);

    DubboInvoker<?> invoker = (DubboInvoker<?>) protocol.refer(IDemoService.class, url);

    long start = System.currentTimeMillis();

    try{
        System.setProperty(Constants.SHUTDOWN_WAIT_KEY, "2000");
        protocol.destroy();
    }finally {
        System.getProperties().remove(Constants.SHUTDOWN_WAIT_KEY);
    }

    long waitTime = System.currentTimeMillis() - start;

    Assert.assertTrue(waitTime >= 2000);
    Assert.assertEquals(false, invoker.isAvailable());
}
 

/**
 * 服务名称不匹配，不能override invoker
 * 服务名称匹配，服务版本号不匹配
 */
@Test
public void testNotifyOverride_notmatch() throws Exception{
    URL newRegistryUrl = registryUrl.addParameter(Constants.EXPORT_KEY, serviceUrl);
    Invoker<RegistryProtocolTest> invoker = new MockInvoker<RegistryProtocolTest>(RegistryProtocolTest.class, newRegistryUrl);
    Exporter<?> exporter = protocol.export(invoker);
    RegistryProtocol rprotocol = RegistryProtocol.getRegistryProtocol();
    NotifyListener listener = getListener(rprotocol);
    List<URL> urls = new ArrayList<URL>();
    urls.add(URL.valueOf("override://0.0.0.0/com.alibaba.dubbo.registry.protocol.HackService?timeout=100"));
    listener.notify(urls);
    assertEquals(true, exporter.getInvoker().isAvailable());
    assertEquals(null, exporter.getInvoker().getUrl().getParameter("timeout"));
    exporter.unexport();
    destroyRegistryProtocol();
}
 

@SuppressWarnings("unchecked")
private <T> ExporterChangeableWrapper<T>  doLocalExport(final Invoker<T> originInvoker){
    String key = getCacheKey(originInvoker);
    ExporterChangeableWrapper<T> exporter = (ExporterChangeableWrapper<T>) bounds.get(key);
    if (exporter == null) {
        synchronized (bounds) {
            exporter = (ExporterChangeableWrapper<T>) bounds.get(key);
            if (exporter == null) {
                final Invoker<?> invokerDelegete = new InvokerDelegete<T>(originInvoker, getProviderUrl(originInvoker));
                exporter = new ExporterChangeableWrapper<T>((Exporter<T>)protocol.export(invokerDelegete), originInvoker);
                bounds.put(key, exporter);
            }
        }
    }
    return (ExporterChangeableWrapper<T>) exporter;
}
 

@Ignore
@Test
public void testRmiProtocol_echoService() throws Exception
   {
    DemoService service = new DemoServiceImpl();
    Exporter<?> rpcExporter = protocol.export(proxy.getInvoker(service, DemoService.class, URL.valueOf("rmi://127.0.0.1:9002/TestService")));
       
    // cast to EchoService
       EchoService echo = proxy.getProxy(protocol.refer(EchoService.class, URL.valueOf("rmi://127.0.0.1:9002/TestService")));
       assertEquals(echo.$echo("test"), "test");
       assertEquals(echo.$echo("abcdefg"), "abcdefg");
       assertEquals(echo.$echo(1234), 1234);
       
       rpcExporter.unexport();
       
       RemoteService remoteService = new RemoteServiceImpl();
       rpcExporter = protocol.export(proxy.getInvoker(remoteService, RemoteService.class, URL.valueOf("rmi://127.0.0.1:9002/remoteService")));
       
       // cast to EchoService
       echo = proxy.getProxy(protocol.refer(EchoService.class, URL.valueOf("rmi://127.0.0.1:9002/remoteService")));
       assertEquals(echo.$echo("test"), "test");
       assertEquals(echo.$echo("abcdefg"), "abcdefg");
       assertEquals(echo.$echo(1234), 1234);
       
       rpcExporter.unexport();
   }
 

public DelegateExporter(Exporter<T> exporter) {
    if (exporter == null) {
        throw new IllegalArgumentException("exporter can not be null");
    } else {
        this.exporter = exporter;
    }
    
}