[CAMEL-3449] Change to allow proxying (of non-serializable beans) to work over protocols such as Mina/Netty

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Won't Fix
• Affects Version/s: 2.5.0
• Fix Version/s: Future
• Component/s: camel-core
• Patch Info: Patch Available
• Assignee: Unassigned
• Reporter: Caspar MacRae
• Created: 20/Dec/10 18:14
• Updated: 11/Jul/15 22:22
• Resolved: 11/Jul/15 22:22

Description

Hi,

Hiding middleware with proxying of Pojos with transports such as JMS, or "direct: ..." is fantastically simple. However problems arise using Mina/Netty - there appears to be an issue with the default serializing codecs for these in that they cannot resolve the declaring class correctly from MethodBean used in BeanInvocation.

I've looked at the documentation and am reasonably confident that it's not a configuration issue, but please enlighten me if it's so.

Not spent long enough on this to understand why this happens - Class.java is Serializable and as the MethodBean is sending a definition not an instance it shouldn't matter whether the target pojo implements Serializable at all? The exceptions thrown are fairly cryptic, NullPointers from the bowels of Object stream deserialization etc.

Anyway, by changing the MethodBean's internal rep to use the class' canonical name it's possible to enjoy painless proxying over these transports. This doesn't break any existing tests but there may be side effects of loading the class on the receiving side (not tested in OSGi or Spring envs).

Also (issue for upstream project) Mina cannot resolve inner classes properly (uses dot not dollar).

Some test code:
---------------------------------------------------------------------------------------------------------------------
import java.io.Serializable;

public interface HelloSerializableService extends HelloService, Serializable {}
---------------------------------------------------------------------------------------------------------------------
public class HelloSerializableServiceImp implements HelloSerializableService {
private static final long serialVersionUID = 1112126394143803848L;
public String sayHelloTo(String who)

{ return "Hello " + who; }
}
---------------------------------------------------------------------------------------------------------------------
public interface HelloService {
public String sayHelloTo(String who);
}
---------------------------------------------------------------------------------------------------------------------
public class HelloServiceImp implements HelloService {
public String sayHelloTo(String who) { return "Hello " + who; }

}
---------------------------------------------------------------------------------------------------------------------
public class MethodBeanClassAsStringTest extends CamelTestSupport {

public static final String DIRECT_TO_NONSERIAL = "direct:nonserial";
public static final String MINA_TO_NONSERIAL = "mina:tcp://0.0.0.0:6060?sync=true&allowDefaultCodec=true";
public static final String MINA_TO_SERIAL = "mina:tcp://0.0.0.0:6065?sync=true&allowDefaultCodec=true";

public MethodBeanClassAsStringTest()

{ setUseRouteBuilder(true); }

@Override
protected RouteBuilder createRouteBuilder() throws Exception {
return new RouteBuilder() {
final HelloService service = new HelloServiceImp();
final HelloSerializableService serialService = new HelloSerializableServiceImp();
@Override
public void configure() throws Exception

{ from(DIRECT_TO_NONSERIAL).bean(service); from(MINA_TO_NONSERIAL).bean(service); from(MINA_TO_SERIAL).bean(serialService); }

};
}

@Test
public void testDirectNonserial() throws Exception {
Endpoint endpoint = context.getEndpoint(DIRECT_TO_NONSERIAL);
HelloService service = createProxy(endpoint, getClass().getClassLoader(), new Class<?>[]

{ HelloService.class});
String response = service.sayHelloTo("Camel");
assertEquals("Hello Camel", response);
}

@Test
public void testMinaNonserial() throws Exception {
Endpoint endpoint = context.getEndpoint(MINA_TO_NONSERIAL);
HelloService service = createProxy(endpoint, getClass().getClassLoader(), new Class<?>[]{ HelloService.class}

);
String response = service.sayHelloTo("Camel");
assertEquals("Hello Camel", response);
}

@Test
public void testMinaSerial() throws Exception {
Endpoint endpoint = context.getEndpoint(MINA_TO_SERIAL);
HelloSerializableService service = createProxy(endpoint, getClass().getClassLoader(), new Class<?>[]

{ HelloSerializableService.class}

);
String response = service.sayHelloTo("Camel");
assertEquals("Hello Camel", response);
}

// https://issues.apache.org/activemq/browse/CAMEL-3341 fixed in 2.6-SNAPSHOT
public static <T> T createProxy(Endpoint endpoint, ClassLoader cl, Class<?>[] interfaces) throws Exception

{ Producer producer = endpoint.createProducer(); ServiceHelper.startService(producer); CamelInvocationHandler invocationHandler = new CamelInvocationHandler(endpoint, producer, new MethodInfoCache(endpoint.getCamelContext())); @SuppressWarnings("unchecked") T retVal = (T) Proxy.newProxyInstance(cl, interfaces, invocationHandler); return retVal; }

}
---------------------------------------------------------------------------------------------------------------------

Exceptions from running the test without the patch:

Sending side:
java.lang.reflect.UndeclaredThrowableException
at $Proxy9.sayHelloTo(Unknown Source)
at net.earcam.camelproxy.MethodBeanClassAsStringTest.testMinaNonserial(MethodBeanClassAsStringTest.java:56)
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.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: org.apache.camel.CamelExchangeException: No response received from remote server: mina://tcp://0.0.0.0:6060?allowDefaultCodec=true&sync=true. Exchange[Message: BeanInvocation public abstract java.lang.String net.earcam.camelproxy.HelloService.sayHelloTo(java.lang.String) with [Camel]]]
at org.apache.camel.component.mina.MinaProducer.process(MinaProducer.java:133)
at org.apache.camel.component.bean.CamelInvocationHandler.invoke(CamelInvocationHandler.java:65)
... 26 more

Recieving side:
837 [Camel Thread 21 - MinaThreadPool] WARN org.apache.camel.component.mina.MinaConsumer$ReceiveHandler - [/127.0.1.1:38374] Unexpected exception from exceptionCaught handler.
org.apache.camel.CamelException: org.apache.mina.filter.codec.ProtocolDecoderException: java.lang.NullPointerException (Hexdump: 00 00 00 FB AC ED 00 05 73 72 01 00 2E 6F 72 67 2E 61 70 61 63 68 65 2E 63 61 6D 65 6C 2E 63 6F 6D 70 6F 6E 65 6E 74 2E 62 65 61 6E 2E 42 65 61 6E 49 6E 76 6F 63 61 74 69 6F 6E 78 70 73 72 01 00 2A 6F 72 67 2E 61 70 61 63 68 65 2E 63 61 6D 65 6C 2E 63 6F 6D 70 6F 6E 65 6E 74 2E 62 65 61 6E 2E 4D 65 74 68 6F 64 42 65 61 6E 78 70 74 00 0A 73 61 79 48 65 6C 6C 6F 54 6F 75 72 01 00 12 5B 4C 6A 61 76 61 2E 6C 61 6E 67 2E 43 6C 61 73 73 3B 78 70 00 00 00 01 76 72 01 00 10 6A 61 76 61 2E 6C 61 6E 67 2E 53 74 72 69 6E 67 78 70 76 72 01 00 22 6E 65 74 2E 65 61 72 63 61 6D 2E 63 61 6D 65 6C 70 72 6F 78 79 2E 48 65 6C 6C 6F 53 65 72 76 69 63 65 78 70 75 72 01 00 13 5B 4C 6A 61 76 61 2E 6C 61 6E 67 2E 4F 62 6A 65 63 74 3B 78 70 00 00 00 01 74 00 05 43 61 6D 65 6C 78)
at org.apache.camel.component.mina.MinaConsumer$ReceiveHandler.exceptionCaught(MinaConsumer.java:92)
at org.apache.mina.common.support.AbstractIoFilterChain$TailFilter.exceptionCaught(AbstractIoFilterChain.java:564)
at org.apache.mina.common.support.AbstractIoFilterChain.callNextExceptionCaught(AbstractIoFilterChain.java:345)
at org.apache.mina.common.support.AbstractIoFilterChain.access$1000(AbstractIoFilterChain.java:53)
at org.apache.mina.common.support.AbstractIoFilterChain$EntryImpl$1.exceptionCaught(AbstractIoFilterChain.java:643)
at org.apache.mina.filter.executor.ExecutorFilter.processEvent(ExecutorFilter.java:224)
at org.apache.mina.filter.executor.ExecutorFilter$ProcessEventsRunnable.run(ExecutorFilter.java:264)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
Caused by: org.apache.mina.filter.codec.ProtocolDecoderException: java.lang.NullPointerException (Hexdump: 00 00 00 FB AC ED 00 05 73 72 01 00 2E 6F 72 67 2E 61 70 61 63 68 65 2E 63 61 6D 65 6C 2E 63 6F 6D 70 6F 6E 65 6E 74 2E 62 65 61 6E 2E 42 65 61 6E 49 6E 76 6F 63 61 74 69 6F 6E 78 70 73 72 01 00 2A 6F 72 67 2E 61 70 61 63 68 65 2E 63 61 6D 65 6C 2E 63 6F 6D 70 6F 6E 65 6E 74 2E 62 65 61 6E 2E 4D 65 74 68 6F 64 42 65 61 6E 78 70 74 00 0A 73 61 79 48 65 6C 6C 6F 54 6F 75 72 01 00 12 5B 4C 6A 61 76 61 2E 6C 61 6E 67 2E 43 6C 61 73 73 3B 78 70 00 00 00 01 76 72 01 00 10 6A 61 76 61 2E 6C 61 6E 67 2E 53 74 72 69 6E 67 78 70 76 72 01 00 22 6E 65 74 2E 65 61 72 63 61 6D 2E 63 61 6D 65 6C 70 72 6F 78 79 2E 48 65 6C 6C 6F 53 65 72 76 69 63 65 78 70 75 72 01 00 13 5B 4C 6A 61 76 61 2E 6C 61 6E 67 2E 4F 62 6A 65 63 74 3B 78 70 00 00 00 01 74 00 05 43 61 6D 65 6C 78)
at org.apache.mina.filter.codec.ProtocolCodecFilter.messageReceived(ProtocolCodecFilter.java:165)
at org.apache.mina.common.support.AbstractIoFilterChain.callNextMessageReceived(AbstractIoFilterChain.java:299)
at org.apache.mina.common.support.AbstractIoFilterChain.access$1100(AbstractIoFilterChain.java:53)
at org.apache.mina.common.support.AbstractIoFilterChain$EntryImpl$1.messageReceived(AbstractIoFilterChain.java:648)
at org.apache.mina.common.support.AbstractIoFilterChain$HeadFilter.messageReceived(AbstractIoFilterChain.java:499)
at org.apache.mina.common.support.AbstractIoFilterChain.callNextMessageReceived(AbstractIoFilterChain.java:299)
at org.apache.mina.common.support.AbstractIoFilterChain.fireMessageReceived(AbstractIoFilterChain.java:293)
at org.apache.mina.transport.socket.nio.SocketIoProcessor.read(SocketIoProcessor.java:228)
at org.apache.mina.transport.socket.nio.SocketIoProcessor.process(SocketIoProcessor.java:198)
at org.apache.mina.transport.socket.nio.SocketIoProcessor.access$400(SocketIoProcessor.java:45)
at org.apache.mina.transport.socket.nio.SocketIoProcessor$Worker.run(SocketIoProcessor.java:485)
at org.apache.mina.util.NamePreservingRunnable.run(NamePreservingRunnable.java:51)
... 3 more
Caused by: java.lang.NullPointerException
at org.apache.mina.common.ByteBuffer$3.resolveClass(ByteBuffer.java:1529)
at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1574)
at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1495)
at java.io.ObjectInputStream.readClass(ObjectInputStream.java:1461)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1311)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1946)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1870)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
at org.apache.camel.component.bean.BeanInvocation.readExternal(BeanInvocation.java:99)
at java.io.ObjectInputStream.readExternalData(ObjectInputStream.java:1791)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1750)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
at org.apache.mina.common.ByteBuffer.getObject(ByteBuffer.java:1537)
at org.apache.mina.filter.codec.serialization.ObjectSerializationDecoder.doDecode(ObjectSerializationDecoder.java:92)
at org.apache.mina.filter.codec.CumulativeProtocolDecoder.decode(CumulativeProtocolDecoder.java:133)
at org.apache.mina.filter.codec.ProtocolCodecFilter.messageReceived(ProtocolCodecFilter.java:158)
... 14 more