Mixing
Different behaviour for lambda and anonymous transformer
2
When a lambda expression is used to define a transformer that accepts a source of type Message, a ClassCastException is raised. However if a semantically identical transformer is defined with an anonymous inner class, no errors occur.
@Bean
public IntegrationFlow lambda(MessageChannel outputChannel) {
return f -> f
.enrichHeaders(h -> h.header("add", 1))
.<Message<Integer>, Integer>transform(m -> m.getPayload() + m.getHeaders().get("add", Integer.class))
.channel(outputChannel);
}
@Bean
public IntegrationFlow anonymous(MessageChannel outputChannel) {
return f -> f
.enrichHeaders(h -> h.header("add", 1))
.transform(new GenericTransformer<Message<Integer>, Integer>() {
@Override
public Integer transform(Message<Integer> source) {
return source.getPayload() + source.getHeaders().get("add", Integer.class);
}
})
.channel(outputChannel);
}
The full stack trace is:
org.springframework.integration.transformer.MessageTransformationException: Failed to transform Message; nested exception is org.springframework.messaging.MessageHandlingException: nested exception is java.lang.ClassCastException: java.lang.Integer cannot be cast to org.springframework.messaging.Message, failedMessage=GenericMessage [payload=0, headers={add=1, id=ed1e39d9-a91b-0bdf-5083-48218ba4e26f, timestamp=1542652005152}], failedMessage=GenericMessage [payload=0, headers={add=1, id=ed1e39d9-a91b-0bdf-5083-48218ba4e26f, timestamp=1542652005152}]
at org.springframework.integration.transformer.MessageTransformingHandler.handleRequestMessage(MessageTransformingHandler.java:114)
at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:123)
at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:169)
at org.springframework.integration.dispatcher.AbstractDispatcher.tryOptimizedDispatch(AbstractDispatcher.java:115)
at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:133)
at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:106)
at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:73)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:459)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:400)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:187)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:166)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:47)
at org.springframework.messaging.core.AbstractMessageSendingTemplate.send(AbstractMessageSendingTemplate.java:109)
at org.springframework.integration.handler.AbstractMessageProducingHandler.sendOutput(AbstractMessageProducingHandler.java:415)
at org.springframework.integration.handler.AbstractMessageProducingHandler.produceOutput(AbstractMessageProducingHandler.java:334)
at org.springframework.integration.handler.AbstractMessageProducingHandler.sendOutputs(AbstractMessageProducingHandler.java:225)
at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:129)
at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:169)
at org.springframework.integration.dispatcher.AbstractDispatcher.tryOptimizedDispatch(AbstractDispatcher.java:115)
at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:133)
at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:106)
at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:73)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:459)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:400)
at org.example.LambdaVsAnonymousTest.lambda(LambdaVsAnonymousTest.java:39)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate(RunBeforeTestExecutionCallbacks.java:74)
at org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate(RunAfterTestExecutionCallbacks.java:84)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:251)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:538)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:760)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:460)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)
Caused by: org.springframework.messaging.MessageHandlingException: nested exception is java.lang.ClassCastException: java.lang.Integer cannot be cast to org.springframework.messaging.Message, failedMessage=GenericMessage [payload=0, headers={add=1, id=ed1e39d9-a91b-0bdf-5083-48218ba4e26f, timestamp=1542652005152}]
at org.springframework.integration.handler.LambdaMessageProcessor.processMessage(LambdaMessageProcessor.java:125)
at org.springframework.integration.transformer.AbstractMessageProcessingTransformer.transform(AbstractMessageProcessingTransformer.java:113)
at org.springframework.integration.transformer.MessageTransformingHandler.handleRequestMessage(MessageTransformingHandler.java:108)
... 55 more
Caused by: java.lang.ClassCastException: java.lang.Integer cannot be cast to org.springframework.messaging.Message
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.integration.handler.LambdaMessageProcessor.processMessage(LambdaMessageProcessor.java:122)
... 57 more
I am wondering which is the desired behaviour; should the transformer be able to accept a Message or should it fail because the payload type is expected? However I think that the behaviour should be identical for both styles.
A sample project can be found here. Please check org.example.LambdaVsAnonymous and org.example.LambdaVsAnonymousTest.
spring-integration
asked Nov 19 '18 at 18:38
Frank SigalasFrank Sigalas
325
add a comment |
2
When a lambda expression is used to define a transformer that accepts a source of type Message, a ClassCastException is raised. However if a semantically identical transformer is defined with an anonymous inner class, no errors occur.
@Bean
public IntegrationFlow lambda(MessageChannel outputChannel) {
return f -> f
.enrichHeaders(h -> h.header("add", 1))
.<Message<Integer>, Integer>transform(m -> m.getPayload() + m.getHeaders().get("add", Integer.class))
.channel(outputChannel);
}
@Bean
public IntegrationFlow anonymous(MessageChannel outputChannel) {
return f -> f
.enrichHeaders(h -> h.header("add", 1))
.transform(new GenericTransformer<Message<Integer>, Integer>() {
@Override
public Integer transform(Message<Integer> source) {
return source.getPayload() + source.getHeaders().get("add", Integer.class);
}
})
.channel(outputChannel);
}
The full stack trace is:
org.springframework.integration.transformer.MessageTransformationException: Failed to transform Message; nested exception is org.springframework.messaging.MessageHandlingException: nested exception is java.lang.ClassCastException: java.lang.Integer cannot be cast to org.springframework.messaging.Message, failedMessage=GenericMessage [payload=0, headers={add=1, id=ed1e39d9-a91b-0bdf-5083-48218ba4e26f, timestamp=1542652005152}], failedMessage=GenericMessage [payload=0, headers={add=1, id=ed1e39d9-a91b-0bdf-5083-48218ba4e26f, timestamp=1542652005152}]
at org.springframework.integration.transformer.MessageTransformingHandler.handleRequestMessage(MessageTransformingHandler.java:114)
at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:123)
at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:169)
at org.springframework.integration.dispatcher.AbstractDispatcher.tryOptimizedDispatch(AbstractDispatcher.java:115)
at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:133)
at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:106)
at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:73)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:459)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:400)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:187)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:166)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:47)
at org.springframework.messaging.core.AbstractMessageSendingTemplate.send(AbstractMessageSendingTemplate.java:109)
at org.springframework.integration.handler.AbstractMessageProducingHandler.sendOutput(AbstractMessageProducingHandler.java:415)
at org.springframework.integration.handler.AbstractMessageProducingHandler.produceOutput(AbstractMessageProducingHandler.java:334)
at org.springframework.integration.handler.AbstractMessageProducingHandler.sendOutputs(AbstractMessageProducingHandler.java:225)
at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:129)
at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:169)
at org.springframework.integration.dispatcher.AbstractDispatcher.tryOptimizedDispatch(AbstractDispatcher.java:115)
at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:133)
at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:106)
at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:73)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:459)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:400)
at org.example.LambdaVsAnonymousTest.lambda(LambdaVsAnonymousTest.java:39)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate(RunBeforeTestExecutionCallbacks.java:74)
at org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate(RunAfterTestExecutionCallbacks.java:84)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:251)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:538)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:760)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:460)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)
Caused by: org.springframework.messaging.MessageHandlingException: nested exception is java.lang.ClassCastException: java.lang.Integer cannot be cast to org.springframework.messaging.Message, failedMessage=GenericMessage [payload=0, headers={add=1, id=ed1e39d9-a91b-0bdf-5083-48218ba4e26f, timestamp=1542652005152}]
at org.springframework.integration.handler.LambdaMessageProcessor.processMessage(LambdaMessageProcessor.java:125)
at org.springframework.integration.transformer.AbstractMessageProcessingTransformer.transform(AbstractMessageProcessingTransformer.java:113)
at org.springframework.integration.transformer.MessageTransformingHandler.handleRequestMessage(MessageTransformingHandler.java:108)
... 55 more
Caused by: java.lang.ClassCastException: java.lang.Integer cannot be cast to org.springframework.messaging.Message
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.integration.handler.LambdaMessageProcessor.processMessage(LambdaMessageProcessor.java:122)
... 57 more
I am wondering which is the desired behaviour; should the transformer be able to accept a Message or should it fail because the payload type is expected? However I think that the behaviour should be identical for both styles.
A sample project can be found here. Please check org.example.LambdaVsAnonymous and org.example.LambdaVsAnonymousTest.
spring-integration
asked Nov 19 '18 at 18:38
Frank SigalasFrank Sigalas
325
add a comment |
2
2
2
When a lambda expression is used to define a transformer that accepts a source of type Message, a ClassCastException is raised. However if a semantically identical transformer is defined with an anonymous inner class, no errors occur.
@Bean
public IntegrationFlow lambda(MessageChannel outputChannel) {
return f -> f
.enrichHeaders(h -> h.header("add", 1))
.<Message<Integer>, Integer>transform(m -> m.getPayload() + m.getHeaders().get("add", Integer.class))
.channel(outputChannel);
}
@Bean
public IntegrationFlow anonymous(MessageChannel outputChannel) {
return f -> f
.enrichHeaders(h -> h.header("add", 1))
.transform(new GenericTransformer<Message<Integer>, Integer>() {
@Override
public Integer transform(Message<Integer> source) {
return source.getPayload() + source.getHeaders().get("add", Integer.class);
}
})
.channel(outputChannel);
}
The full stack trace is:
org.springframework.integration.transformer.MessageTransformationException: Failed to transform Message; nested exception is org.springframework.messaging.MessageHandlingException: nested exception is java.lang.ClassCastException: java.lang.Integer cannot be cast to org.springframework.messaging.Message, failedMessage=GenericMessage [payload=0, headers={add=1, id=ed1e39d9-a91b-0bdf-5083-48218ba4e26f, timestamp=1542652005152}], failedMessage=GenericMessage [payload=0, headers={add=1, id=ed1e39d9-a91b-0bdf-5083-48218ba4e26f, timestamp=1542652005152}]
at org.springframework.integration.transformer.MessageTransformingHandler.handleRequestMessage(MessageTransformingHandler.java:114)
at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:123)
at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:169)
at org.springframework.integration.dispatcher.AbstractDispatcher.tryOptimizedDispatch(AbstractDispatcher.java:115)
at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:133)
at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:106)
at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:73)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:459)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:400)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:187)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:166)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:47)
at org.springframework.messaging.core.AbstractMessageSendingTemplate.send(AbstractMessageSendingTemplate.java:109)
at org.springframework.integration.handler.AbstractMessageProducingHandler.sendOutput(AbstractMessageProducingHandler.java:415)
at org.springframework.integration.handler.AbstractMessageProducingHandler.produceOutput(AbstractMessageProducingHandler.java:334)
at org.springframework.integration.handler.AbstractMessageProducingHandler.sendOutputs(AbstractMessageProducingHandler.java:225)
at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:129)
at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:169)
at org.springframework.integration.dispatcher.AbstractDispatcher.tryOptimizedDispatch(AbstractDispatcher.java:115)
at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:133)
at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:106)
at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:73)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:459)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:400)
at org.example.LambdaVsAnonymousTest.lambda(LambdaVsAnonymousTest.java:39)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate(RunBeforeTestExecutionCallbacks.java:74)
at org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate(RunAfterTestExecutionCallbacks.java:84)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:251)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:538)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:760)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:460)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)
Caused by: org.springframework.messaging.MessageHandlingException: nested exception is java.lang.ClassCastException: java.lang.Integer cannot be cast to org.springframework.messaging.Message, failedMessage=GenericMessage [payload=0, headers={add=1, id=ed1e39d9-a91b-0bdf-5083-48218ba4e26f, timestamp=1542652005152}]
at org.springframework.integration.handler.LambdaMessageProcessor.processMessage(LambdaMessageProcessor.java:125)
at org.springframework.integration.transformer.AbstractMessageProcessingTransformer.transform(AbstractMessageProcessingTransformer.java:113)
at org.springframework.integration.transformer.MessageTransformingHandler.handleRequestMessage(MessageTransformingHandler.java:108)
... 55 more
Caused by: java.lang.ClassCastException: java.lang.Integer cannot be cast to org.springframework.messaging.Message
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.integration.handler.LambdaMessageProcessor.processMessage(LambdaMessageProcessor.java:122)
... 57 more
I am wondering which is the desired behaviour; should the transformer be able to accept a Message or should it fail because the payload type is expected? However I think that the behaviour should be identical for both styles.
A sample project can be found here. Please check org.example.LambdaVsAnonymous and org.example.LambdaVsAnonymousTest.
spring-integration
asked Nov 19 '18 at 18:38
Frank SigalasFrank Sigalas
325
When a lambda expression is used to define a transformer that accepts a source of type Message, a ClassCastException is raised. However if a semantically identical transformer is defined with an anonymous inner class, no errors occur.
@Bean
public IntegrationFlow lambda(MessageChannel outputChannel) {
return f -> f
.enrichHeaders(h -> h.header("add", 1))
.<Message<Integer>, Integer>transform(m -> m.getPayload() + m.getHeaders().get("add", Integer.class))
.channel(outputChannel);
}
@Bean
public IntegrationFlow anonymous(MessageChannel outputChannel) {
return f -> f
.enrichHeaders(h -> h.header("add", 1))
.transform(new GenericTransformer<Message<Integer>, Integer>() {
@Override
public Integer transform(Message<Integer> source) {
return source.getPayload() + source.getHeaders().get("add", Integer.class);
}
})
.channel(outputChannel);
}
The full stack trace is:
org.springframework.integration.transformer.MessageTransformationException: Failed to transform Message; nested exception is org.springframework.messaging.MessageHandlingException: nested exception is java.lang.ClassCastException: java.lang.Integer cannot be cast to org.springframework.messaging.Message, failedMessage=GenericMessage [payload=0, headers={add=1, id=ed1e39d9-a91b-0bdf-5083-48218ba4e26f, timestamp=1542652005152}], failedMessage=GenericMessage [payload=0, headers={add=1, id=ed1e39d9-a91b-0bdf-5083-48218ba4e26f, timestamp=1542652005152}]
at org.springframework.integration.transformer.MessageTransformingHandler.handleRequestMessage(MessageTransformingHandler.java:114)
at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:123)
at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:169)
at org.springframework.integration.dispatcher.AbstractDispatcher.tryOptimizedDispatch(AbstractDispatcher.java:115)
at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:133)
at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:106)
at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:73)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:459)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:400)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:187)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:166)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:47)
at org.springframework.messaging.core.AbstractMessageSendingTemplate.send(AbstractMessageSendingTemplate.java:109)
at org.springframework.integration.handler.AbstractMessageProducingHandler.sendOutput(AbstractMessageProducingHandler.java:415)
at org.springframework.integration.handler.AbstractMessageProducingHandler.produceOutput(AbstractMessageProducingHandler.java:334)
at org.springframework.integration.handler.AbstractMessageProducingHandler.sendOutputs(AbstractMessageProducingHandler.java:225)
at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:129)
at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:169)
at org.springframework.integration.dispatcher.AbstractDispatcher.tryOptimizedDispatch(AbstractDispatcher.java:115)
at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:133)
at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:106)
at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:73)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:459)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:400)
at org.example.LambdaVsAnonymousTest.lambda(LambdaVsAnonymousTest.java:39)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate(RunBeforeTestExecutionCallbacks.java:74)
at org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate(RunAfterTestExecutionCallbacks.java:84)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:251)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:538)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:760)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:460)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)
Caused by: org.springframework.messaging.MessageHandlingException: nested exception is java.lang.ClassCastException: java.lang.Integer cannot be cast to org.springframework.messaging.Message, failedMessage=GenericMessage [payload=0, headers={add=1, id=ed1e39d9-a91b-0bdf-5083-48218ba4e26f, timestamp=1542652005152}]
at org.springframework.integration.handler.LambdaMessageProcessor.processMessage(LambdaMessageProcessor.java:125)
at org.springframework.integration.transformer.AbstractMessageProcessingTransformer.transform(AbstractMessageProcessingTransformer.java:113)
at org.springframework.integration.transformer.MessageTransformingHandler.handleRequestMessage(MessageTransformingHandler.java:108)
... 55 more
Caused by: java.lang.ClassCastException: java.lang.Integer cannot be cast to org.springframework.messaging.Message
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.integration.handler.LambdaMessageProcessor.processMessage(LambdaMessageProcessor.java:122)
... 57 more
I am wondering which is the desired behaviour; should the transformer be able to accept a Message or should it fail because the payload type is expected? However I think that the behaviour should be identical for both styles.
A sample project can be found here. Please check org.example.LambdaVsAnonymous and org.example.LambdaVsAnonymousTest.
spring-integration
spring-integration
asked Nov 19 '18 at 18:38
Frank SigalasFrank Sigalas
325
asked Nov 19 '18 at 18:38
Frank SigalasFrank Sigalas
325
asked Nov 19 '18 at 18:38
Frank SigalasFrank Sigalas
325
asked Nov 19 '18 at 18:38
Frank SigalasFrank Sigalas
325
asked Nov 19 '18 at 18:38
Frank SigalasFrank Sigalas
325
325
add a comment |
add a comment |
2 Answers
2
active
oldest
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3
I believe you have to use the typed variant of the transform(..). For example .transform(Message.class, m -> m.getPayload() + m.getHeaders().get("add", Integer.class)).
That said I believe we should improve javadoc a bit since it talks about <P> the payload type - 'transform from' while it should simply talk about type of input transformer should accept. .
answered Nov 19 '18 at 19:24
Oleg ZhurakouskyOleg Zhurakousky
1,36666
The PR on the matter has been merged github.com/spring-projects/spring-integration/pull/2636
– Artem Bilan
Nov 19 '18 at 22:00
add a comment |
1
It's a limitation of Java Lambdas.
Method.getParameterTypes()
just returns Object when invoked on a Lambda.
The type information here...
.<Message<Integer>, Integer>transform(m -> m.getPayload() + m.getHeaders().get("add", Integer.class))
...is just syntactic sugar to allow you to reference the proper types in the lambda (similar to doing explicit casting within the lambda). It is not baked into the lambda.
There is just no way to infer that the lambda expects a Message<?>.
With the anonymous inner class, the type information is retained since the method has concrete types.
answered Nov 19 '18 at 19:19
Gary RussellGary Russell
79.2k74471
Also see Oleg's answer regarding the use of the overloaded.transformthat takes an explicit from type.
– Gary Russell
Nov 19 '18 at 19:36
I switched the accepted answer as it provides a concrete solution to my problem, however this one provides some insight as to what actually happens. I wish I could accept both!
– Frank Sigalas
Nov 19 '18 at 19:52
Understood - no problem here.
– Gary Russell
Nov 19 '18 at 19:57
add a comment |
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2 Answers
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active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
3
I believe you have to use the typed variant of the transform(..). For example .transform(Message.class, m -> m.getPayload() + m.getHeaders().get("add", Integer.class)).
That said I believe we should improve javadoc a bit since it talks about <P> the payload type - 'transform from' while it should simply talk about type of input transformer should accept. .
answered Nov 19 '18 at 19:24
Oleg ZhurakouskyOleg Zhurakousky
1,36666
The PR on the matter has been merged github.com/spring-projects/spring-integration/pull/2636
– Artem Bilan
Nov 19 '18 at 22:00
add a comment |
3
I believe you have to use the typed variant of the transform(..). For example .transform(Message.class, m -> m.getPayload() + m.getHeaders().get("add", Integer.class)).
That said I believe we should improve javadoc a bit since it talks about <P> the payload type - 'transform from' while it should simply talk about type of input transformer should accept. .
answered Nov 19 '18 at 19:24
Oleg ZhurakouskyOleg Zhurakousky
1,36666
The PR on the matter has been merged github.com/spring-projects/spring-integration/pull/2636
– Artem Bilan
Nov 19 '18 at 22:00
add a comment |
3
3
3
I believe you have to use the typed variant of the transform(..). For example .transform(Message.class, m -> m.getPayload() + m.getHeaders().get("add", Integer.class)).
That said I believe we should improve javadoc a bit since it talks about <P> the payload type - 'transform from' while it should simply talk about type of input transformer should accept. .
answered Nov 19 '18 at 19:24
Oleg ZhurakouskyOleg Zhurakousky
1,36666
I believe you have to use the typed variant of the transform(..). For example .transform(Message.class, m -> m.getPayload() + m.getHeaders().get("add", Integer.class)).
That said I believe we should improve javadoc a bit since it talks about <P> the payload type - 'transform from' while it should simply talk about type of input transformer should accept. .
answered Nov 19 '18 at 19:24
Oleg ZhurakouskyOleg Zhurakousky
1,36666
answered Nov 19 '18 at 19:24
Oleg ZhurakouskyOleg Zhurakousky
1,36666
answered Nov 19 '18 at 19:24
Oleg ZhurakouskyOleg Zhurakousky
1,36666
answered Nov 19 '18 at 19:24
Oleg ZhurakouskyOleg Zhurakousky
1,36666
1,36666
The PR on the matter has been merged github.com/spring-projects/spring-integration/pull/2636
– Artem Bilan
Nov 19 '18 at 22:00
add a comment |
The PR on the matter has been merged github.com/spring-projects/spring-integration/pull/2636
– Artem Bilan
Nov 19 '18 at 22:00
The PR on the matter has been merged github.com/spring-projects/spring-integration/pull/2636
– Artem Bilan
Nov 19 '18 at 22:00
The PR on the matter has been merged github.com/spring-projects/spring-integration/pull/2636
– Artem Bilan
Nov 19 '18 at 22:00
add a comment |
1
It's a limitation of Java Lambdas.
Method.getParameterTypes()
just returns Object when invoked on a Lambda.
The type information here...
.<Message<Integer>, Integer>transform(m -> m.getPayload() + m.getHeaders().get("add", Integer.class))
...is just syntactic sugar to allow you to reference the proper types in the lambda (similar to doing explicit casting within the lambda). It is not baked into the lambda.
There is just no way to infer that the lambda expects a Message<?>.
With the anonymous inner class, the type information is retained since the method has concrete types.
answered Nov 19 '18 at 19:19
Gary RussellGary Russell
79.2k74471
Also see Oleg's answer regarding the use of the overloaded.transformthat takes an explicit from type.
– Gary Russell
Nov 19 '18 at 19:36
I switched the accepted answer as it provides a concrete solution to my problem, however this one provides some insight as to what actually happens. I wish I could accept both!
– Frank Sigalas
Nov 19 '18 at 19:52
Understood - no problem here.
– Gary Russell
Nov 19 '18 at 19:57
add a comment |
1
It's a limitation of Java Lambdas.
Method.getParameterTypes()
just returns Object when invoked on a Lambda.
The type information here...
.<Message<Integer>, Integer>transform(m -> m.getPayload() + m.getHeaders().get("add", Integer.class))
...is just syntactic sugar to allow you to reference the proper types in the lambda (similar to doing explicit casting within the lambda). It is not baked into the lambda.
There is just no way to infer that the lambda expects a Message<?>.
With the anonymous inner class, the type information is retained since the method has concrete types.
answered Nov 19 '18 at 19:19
Gary RussellGary Russell
79.2k74471
Also see Oleg's answer regarding the use of the overloaded.transformthat takes an explicit from type.
– Gary Russell
Nov 19 '18 at 19:36
I switched the accepted answer as it provides a concrete solution to my problem, however this one provides some insight as to what actually happens. I wish I could accept both!
– Frank Sigalas
Nov 19 '18 at 19:52
Understood - no problem here.
– Gary Russell
Nov 19 '18 at 19:57
add a comment |
1
1
1
It's a limitation of Java Lambdas.
Method.getParameterTypes()
just returns Object when invoked on a Lambda.
The type information here...
.<Message<Integer>, Integer>transform(m -> m.getPayload() + m.getHeaders().get("add", Integer.class))
...is just syntactic sugar to allow you to reference the proper types in the lambda (similar to doing explicit casting within the lambda). It is not baked into the lambda.
There is just no way to infer that the lambda expects a Message<?>.
With the anonymous inner class, the type information is retained since the method has concrete types.
answered Nov 19 '18 at 19:19
Gary RussellGary Russell
79.2k74471
It's a limitation of Java Lambdas.
Method.getParameterTypes()
just returns Object when invoked on a Lambda.
The type information here...
.<Message<Integer>, Integer>transform(m -> m.getPayload() + m.getHeaders().get("add", Integer.class))
...is just syntactic sugar to allow you to reference the proper types in the lambda (similar to doing explicit casting within the lambda). It is not baked into the lambda.
There is just no way to infer that the lambda expects a Message<?>.
With the anonymous inner class, the type information is retained since the method has concrete types.
answered Nov 19 '18 at 19:19
Gary RussellGary Russell
79.2k74471
answered Nov 19 '18 at 19:19
Gary RussellGary Russell
79.2k74471
answered Nov 19 '18 at 19:19
Gary RussellGary Russell
79.2k74471
answered Nov 19 '18 at 19:19
Gary RussellGary Russell
79.2k74471
79.2k74471
Also see Oleg's answer regarding the use of the overloaded.transformthat takes an explicit from type.
– Gary Russell
Nov 19 '18 at 19:36
I switched the accepted answer as it provides a concrete solution to my problem, however this one provides some insight as to what actually happens. I wish I could accept both!
– Frank Sigalas
Nov 19 '18 at 19:52
Understood - no problem here.
– Gary Russell
Nov 19 '18 at 19:57
add a comment |
Also see Oleg's answer regarding the use of the overloaded.transformthat takes an explicit from type.
– Gary Russell
Nov 19 '18 at 19:36
I switched the accepted answer as it provides a concrete solution to my problem, however this one provides some insight as to what actually happens. I wish I could accept both!
– Frank Sigalas
Nov 19 '18 at 19:52
Understood - no problem here.
– Gary Russell
Nov 19 '18 at 19:57
Also see Oleg's answer regarding the use of the overloaded
.transform that takes an explicit from type.– Gary Russell
Nov 19 '18 at 19:36
Also see Oleg's answer regarding the use of the overloaded
.transform that takes an explicit from type.– Gary Russell
Nov 19 '18 at 19:36
I switched the accepted answer as it provides a concrete solution to my problem, however this one provides some insight as to what actually happens. I wish I could accept both!
– Frank Sigalas
Nov 19 '18 at 19:52
I switched the accepted answer as it provides a concrete solution to my problem, however this one provides some insight as to what actually happens. I wish I could accept both!
– Frank Sigalas
Nov 19 '18 at 19:52
Understood - no problem here.
– Gary Russell
Nov 19 '18 at 19:57
Understood - no problem here.
– Gary Russell
Nov 19 '18 at 19:57
add a comment |
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