Split and Aggregate - Old Exchange is null everytime in AggregationStrategy

[dinesh19aug]

Hi,
  I see that this question has been asked a number of times but none of post
helped or had a conclusive solution. I am splitting a message and then
aggregating it using Aggregator2. The code was throwing exception because
oldExchange was always null. So to test I designed a small code.

I read an orders,xml file which looks like this
<Orders xmlns="http://some/schema/Order";>
        <Order>
                <orderNum>1</orderNum>
        </Order>
        <Order>
                <orderNum>2</orderNum>
        </Order>
        <Order>
                <orderNum>3</orderNum>
        </Order>
        <Order>
                <orderNum>5</orderNum>
        </Order>
        <Order>
                <orderNum>6</orderNum>
        </Order>
</Orders>

My camel Context Looks like this
<camel:camelContext xmlns="http://camel.apache.org/schema/spring";
xmlns:te="http://acn/schema/Order";>
    
    <camel:route>
        <camel:from uri="file:src/data/catask/test?noop=true"/>
        <camel:log message="${body}"></camel:log>
        <camel:split>
                <camel:xpath>//te:Orders/*</camel:xpath>
                <camel:to uri="direct:logQueries"/>
                 <camel:to uri="direct:aggegateQueries"/> 
        </camel:split>
 
    </camel:route>
    
    <camel:route>
        <camel:from uri="direct:logQueries"/>
        <camel:log message="After the call : \n ${body}"></camel:log> 
    </camel:route>
    
     <camel:route>
        <camel:from uri="direct:aggegateQueries"/>
        <camel:aggregate strategyRef="aggrTask" completionInterval="8000" >
                <camel:correlationExpression>
                        <camel:xpath>//te:Order</camel:xpath>
                </camel:correlationExpression>
                 <camel:to 
uri="file:src/data/catask/output?fileName=output.xml"/> 

        </camel:aggregate>
    </camel:route> 
    
  </camel:camelContext>

My Aggregation Strategy class looks like this
                public Exchange aggregate(Exchange oldExchange, Exchange 
newExchange) {
                if (oldExchange == null) {
                        System.out.println("Returning new exchange");
                    return newExchange;
                }
         
                String oldBody = oldExchange.getIn().getBody(String.class);
                String newBody = newExchange.getIn().getBody(String.class);
                oldExchange.getIn().setBody(oldBody + "+" + newBody);
                return oldExchange;
            }


The problem is that when the aggregated result is saved in output.xml file
it contains only the last record it read from Orders.xml.

i.e.
<Order xmlns="http://some/schema/Order";>
                <orderNum>6</orderNum>
        </Order>



I looked into it further and found that this was happening because after the
first call oldExchange should have some value but it turns out it is always
null. I think that because it is reading everything from a single file and
splitting it, there is only exchange.

Any suggestions??



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