[ Camel: exception with Camel and Multicast EIP ]

I have a simple case where I use multicast with 3 beans. The thirs beans returns a RuntimeException but that's fine because it does not prevent the response from being returned back to the client (servlet call). However if I add a dynamicRouter between the from and the multicast then no more response is returned and I have Camel trying to handle the exception differently as before by resending the message to the multicast. This leads to conversion exceptions because in my aggregator I modify the IN message.

How can I keep the same behaviour and use a dynamicRouter?

Thanks

Below are some extract of the files I'm using:

camel.xml

    <!-- Generic route listening to all the the requests -->
    <route id="generic">
        <from uri="servlet:///services?httpBindingRef=rsaHttpBinding"/>
   <!-- <dynamicRouter>
          <method ref="rsaDynamicRouter" method="route"/>
        </dynamicRouter>
    -->
        <choice> 
            <when> 
                <simple>${property.rsaHeader.action} == 'getAccounts'</simple>
                <to uri="direct:getAccounts#1.0" /> 
            </when> 
            <when>
                <simple>${property.rsaHeader.action} == 'createAccount'</simple>
                <to uri="direct:createAccount#1.0" /> 
            </when> 
        </choice>
    </route>

    <!-- Process getAccounts requests -->
    <route>
        <from uri="direct:getAccounts#1.0" />
        <multicast strategyRef="accountAggregator">
            <to uri="bean:accountBackend1?method=getAccounts" />
            <to uri="bean:accountBackend2?method=getAccounts" />
            <to uri="bean:accountBackend3?method=getAccounts" />
        </multicast>
    </route>

RsaDynamicRouter.java

public class RsaDynamicRouter {
    public String route(Object body, @Properties Map<String, Object> properties) {
    RsaHeader rsaHeader = (RsaHeader)properties.get("rsaHeader");

    return "direct://" + rsaHeader.getAction() + "#" + rsaHeader.getVersion();
    }
}

If I uncomment the dynamicRouter and comment the choice then I receive response is not sent back to client and I have the following exception which occurs 3 times:

Caused by: org.apache.camel.InvalidPayloadException: No body available of type: lu.bgl.example.mycamel.account.SearchCriteria but has value: [Account: number= 1314-1516-1718-1920, name=Larry Page, balance=30, Account: number= 2122-2324-2526-2728, name=Steve Jobs, balance=40] of type: java.util.ArrayList on: Message: [Account: number= 1314-1516-1718-1920, name=Larry Page, balance=30, Account: number= 2122-2324-2526-2728, name=Steve Jobs, balance=40]. Caused by: No type converter available to convert from type: java.util.ArrayList to the required type: lu.bgl.example.mycamel.account.SearchCriteria with value [Account: number= 1314-1516-1718-1920, name=Larry Page, balance=30, Account: number= 2122-2324-2526-2728, name=Steve Jobs, balance=40]. Exchange[Message: [Account: number= 1314-1516-1718-1920, name=Larry Page, balance=30, Account: number= 2122-2324-2526-2728, name=Steve Jobs, balance=40]]. Caused by: [org.apache.camel.NoTypeConversionAvailableException - No type converter available to convert from type: java.util.ArrayList to the required type: lu.bgl.example.mycamel.account.SearchCriteria with value [Account: number= 1314-1516-1718-1920, name=Larry Page, balance=30, Account: number= 2122-2324-2526-2728, name=Steve Jobs, balance=40]]
    at org.apache.camel.impl.MessageSupport.getMandatoryBody(MessageSupport.java:101) ~[camel-core-2.11.0.jar:2.11.0]
    at org.apache.camel.builder.ExpressionBuilder$38.evaluate(ExpressionBuilder.java:934) ~[camel-core-2.11.0.jar:2.11.0]
    ... 131 common frames omitted
Caused by: org.apache.camel.NoTypeConversionAvailableException: No type converter available to convert from type: java.util.ArrayList to the required type: lu.bgl.example.mycamel.account.SearchCriteria with value [Account: number= 1314-1516-1718-1920, name=Larry Page, balance=30, Account: number= 2122-2324-2526-2728, name=Steve Jobs, balance=40]
    at org.apache.camel.impl.converter.BaseTypeConverterRegistry.mandatoryConvertTo(BaseTypeConverterRegistry.java:181) ~[camel-core-2.11.0.jar:2.11.0]
    at org.apache.camel.impl.MessageSupport.getMandatoryBody(MessageSupport.java:99) ~[camel-core-2.11.0.jar:2.11.0]
    ... 132 common frames omitted

Answer 1

OK found it!

Dynamic router must return null otherwise it keeps on retrying to execute the route! I was expecting only one routing not multiple routing. Dynamic router is more like a coordinator.

Anyway here is my code for the Dynamic router which works:

public class RsaDynamicRouter {
    public String route(Object body, @Properties Map<String, Object> properties) {
        RsaHeader rsaHeader = (RsaHeader)properties.get("rsaHeader");

        if (properties.get("endDynamicRouting") == null) {
            properties.put("endDynamicRouting", "dummy");
            return "direct://" + rsaHeader.getAction() + "#" + rsaHeader.getVersion();
        } else {
            return null;
        }
    }
}