THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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MyEndpoint.java- ExtendsEndpointand implementsExchangeProcessor.Endpointprovides a referenceable resource for the component and theExchangeProcessorprovides the ability for the JBI container to process a message exchange with the component. TheExchangeProcessor.process()method is where we will place make a call to a method containing the logic to print out the Hello World message.
Adding the Logic to Print the Message
When creating a JBI component, how a message exchange is handled depends on whether a component is a consumer or a provider. Because the Hello World SE will not be consuming any other service (i.e., sending a message to another service), it is a provider (i.e., it will only be providing its service via a return message). As mentioned above, the ExchangeProcessor.process() method is of interest because it is where the message exchange is handled, so let's examine this method:
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public void process(MessageExchange exchange) throws Exception {
// The component acts as a provider, this means that another component has requested our service
// As this exchange is active, this is either an in or a fault (out are send by this component)
if (exchange.getRole() == MessageExchange.Role.PROVIDER) {
// Check here if the mep is supported by this component
if (exchange instanceof InOut == false) {
throw new UnsupportedOperationException("Unsupported MEP: " + exchange.getPattern());
}
// In message
if (exchange.getMessage("in") != null) {
NormalizedMessage in = exchange.getMessage("in");
// TODO ... handle the in message
// If the MEP is an InOnly, RobustInOnly, you have to set the exchange to DONE status
// else, you have to create an Out message and populate it
// For now, just echo back
NormalizedMessage out = exchange.createMessage();
out.setContent(in.getContent());
exchange.setMessage(out, "out");
channel.send(exchange);
// Fault message
} else if (exchange.getFault() != null) {
// TODO ... handle the fault
exchange.setStatus(ExchangeStatus.DONE);
channel.send(exchange);
// This is not compliant with the default MEPs
} else {
throw new IllegalStateException("Provider exchange is ACTIVE, but no in or fault is provided");
}
// The component acts as a consumer, this means this exchange is received because
// we sent it to another component. As it is active, this is either an out or a fault
// If this component does not create / send exchanges, you may just throw an UnsupportedOperationException
} else if (exchange.getRole() == MessageExchange.Role.CONSUMER) {
// Exchange is finished
if (exchange.getStatus() == ExchangeStatus.DONE) {
return;
// Exchange has been aborted with an exception
} else if (exchange.getStatus() == ExchangeStatus.ERROR) {
return;
// Exchange is active
} else {
// Out message
if (exchange.getMessage("out") != null) {
// TODO ... handle the response
exchange.setStatus(ExchangeStatus.DONE);
channel.send(exchange);
// Fault message
} else if (exchange.getFault() != null) {
// TODO ... handle the fault
exchange.setStatus(ExchangeStatus.DONE);
channel.send(exchange);
// This is not compliant with the default MEPs
} else {
throw new IllegalStateException("Consumer exchange is ACTIVE, but no out or fault is provided");
}
}
// Unknown role
} else {
throw new IllegalStateException("Unkown role: " + exchange.getRole());
}
}
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The implementation of this method was provided by the servicemix-service-engine Maven archetype and is shown in the code snippet above. Because the archetype can be used to create a consumer or a provider, this snippet contains a conditional block for handling either a consuemr or a provider role. In the case of the Hello World SE, we are only interested in the provider role so we're going to make some changes to MyEndpoint.
Instead of extending the Endpoint class, we're going to extend a different class that is specifically for providers named ProviderEndpoint. This class provides some additional conveniences for providers and will make the job of implementing MyEndpoint as a provider much easier.
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Creating the Maven Subprojects For the Service Unit and Service Assembly
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