Camel Exchange property not evaluating with simple in xml - properties

Question

I'm trying to set a property isEven on the Exchange.property and then use choice when to evaluate it in the route.
The property is being set but I am always getting the otherwise result (NACK) no matter what isEven is set to.
Here is where I set it:
// Below is used for development
// If the property.isEven == true then an ACK will be returned from the Mock HRM
// If false then NACK
int lastDigit = Integer.parseInt(exchange.getExchangeId().substring(exchange.getExchangeId().length() - 1));
// check if lastDigit is odd or even
if ((lastDigit & 1) == 0)
{
exchange.setProperty("isEven", Boolean.TRUE);
System.out.println("\n\n\n********** Exchange Id lastDigit " + lastDigit + " isEven: " + exchange.getProperty("isEven") + " ***********");
}
else
{
exchange.setProperty("isEven", Boolean.FALSE);
System.out.println("\n\n\n********** Exchange Id lastDigit " + lastDigit + " isEven: " + exchange.getProperty("isEven") + " ***********");
}
The println's show that I am setting isEven the way I expect.
Here is the route:
<!-- Used to ramdomly send Ack or Nack -->
<log message="isEven property is :: ${property[isEven]}" />
<camel:choice>
<camel:when>
<simple>"${property[isEven]}"</simple>
<transform>
<constant>ACK</constant>
</transform>
</camel:when>
<camel:otherwise>
<transform>
<constant>NACK</constant>
</transform>
</camel:otherwise>
</camel:choice>
The log message never evaluates the expression ${property[isEven]}
Here is the output
log[isEven property is :: ${property[isEven]}]
if I change the simple expression to explicitly check for true I alway get ACK no matter what the property is set to.
<simple>"${property[isEven]} == true"</simple>
I have searched the web but couldn't find a lot of examples using simple and Exchange property.
Can anyone see what I'm missing?
Thanks,
Andrew
After Peter showed he could do it easily I tried 2 of his examples that I hadn't tried already. Here is one. It didn't work for me. It generated Hello :: NACK whether isEven is true or false:
<camel:choice>
<camel:when>
<simple>${property[isEven]} == "true"</simple>
<log message="HELLO :: ACK" />
<!-- <transform>
<constant>ACK</constant>
</transform> -->
</camel:when>
<camel:otherwise>
<log message="HELLO :: NACK" />
<!-- <transform>
<constant>NACK</constant>
</transform> -->
</camel:otherwise>
</camel:choice>
Here is something interesting. It looks below like the log is saying its empty On the last like
********** Exchange Id lastDigit 2 isEven: true ***********
14/02/20 14:09:13 INFO interceptor.Tracer: >>> (toHRMRoute) bean://hl7handler?method=handleORM --> log[isEven property is :: ${property[isEven]}] <<< Pattern:InOut, Properties {CamelToEndpoint=bean://hl7handler?method=handleORM, CamelMessageHistory [DefaultMessageHistory[routeId=toHRMRoute, node=to3], DefaultMessage History[routeId=toHRMRoute, node=log1]], CamelCreatedTimestamp=Thu Feb 20 14:09:13 CST 2014}
14/02/20 14:09:13 INFO toHRMRoute: ** isEven property is :: **
I think Peter is correct in that it has to be the way I have my routes set up.
<endpoint id="hrmMockHL7Listener"
uri="netty:tcp://localhost:9200?sync=true" />
<!-- Sending data using postman to a rest server-->
<route id="pushRESTRoute">
<from uri="cxfrs://bean://pushRESTServer" />
<!-- this process is where we set isEven on the Exchange-->
<process ref="transformer"/>
<!-- Send it to a tcp listener at port 9200-->
<to ref="hrmMockHL7Listener" />
</route>
<!-- Changed routes does the Exchange keep properties? -->
<route id="toMRoute">
<from uri="hrmMockHL7Listener" />
<to uri="bean:hl7handler?method=handleORM" />
<!-- Used to ramdomly send Ack or Nack -->
<log message="isEven property is :: ${property[isEven]}">
// see the beginning of the question for choice code.
Looking at the output it seems the isEven property is being dropped between routes:
14/02/21 09:37:26 INFO interceptor.Tracer: >>> (pushRESTRoute) ref:transformer --> tcp://localhost:9200 <<< Pattern:InOut, Properties {CamelMessageHistory=[DefaultMessageHistory[routeId=pushRESTRoute, node=process1], DefaultMessageHistory[routeId=pushRESTRoute, node=to1]], CamelCreatedTimestamp=Fri Feb 21 09:37:26 CST 2014, isEven=true}
See isEven at the end? The next tracer that comes doesn't have it
/02/21 09:37:26 INFO interceptor.Tracer: >>> (toMRoute) from(tcp://localhost:9200) --> bean://hl7handler?method=handleORM <<< Pattern:InOut, Properties:{CamellMessageHistory=[DefaultMessageHistory[routeId=toMRoute, node=to3]], CamelCreatedTimestamp=Fri Feb 21 09:37:26 CST 2014}
From the Exchange javadoc
An Exchange is the message container holding the information during the entire routing of a Message received by a Consumer.
Does entire include across differents routes?

Answer 1

For testing I changed the route a little bit:
<route id="startRoute">
<from uri="direct:start" />
<multicast stopOnException="true">
<to uri="direct:trigger" />
<to uri="direct:trigger" />
<to uri="direct:trigger" />
</multicast>
</route>
<route>
<from uri="direct:trigger" />
<process ref="myProcessor" />
<log message="isEven property is :: ${property[isEven]}" />
<camel:choice>
<camel:when>
<simple>"${property.isEven}"</simple>
<log message="HELLO :: ACK" />
</camel:when>
<camel:otherwise>
<log message="HELLO :: NACK" />
</camel:otherwise>
</camel:choice>
</route>
<!-- scope singleton is default -->
<bean id="myProcessor" class="ch.keller.test.testcamelspring.util.Trigger" scope="singleton" />
The processor is defined as follows:
public class Trigger implements Processor {
#Override
public void process(final Exchange exchange) throws Exception {
// your code comes here
}
}
For me, following expressions worked as expected:
<simple>"${property[isEven]}"</simple>
or
<simple>${property[isEven]}</simple>
or
<simple>${property[isEven]} == "true"</simple>
or
<simple>"${property.isEven}"</simple>
or
<simple>${property.isEven} == "true"</simple>
or
<simple>${property.isEven}</simple>
I prefer the last version.
EDIT:
In order to debug if the property is correctly set, enable showProperties in your Spring configuration file:
<bean id="traceFormatter" class="org.apache.camel.processor.interceptor.DefaultTraceFormatter">
<property name="showBreadCrumb" value="false" />
<property name="showProperties" value="true" />
</bean>
Then you should see following output in your log (shorten for better readability):
[main] Tracer INFO >>> (route1) log[isEven property is :: ${property[isEven]}] --> choice <<< Pattern:InOnly, Properties:{CamelToEndpoint=direct://trigger, ..., isEven=true, ...
The important part is isEven=true.
EDIT:
The property is kept when forwarding to another route which can be proven as follows:
<route>
<from uri="direct:trigger" />
<process ref="myProcessor" />
<log message="isEven property is :: ${property[isEven]}" />
<to uri="direct:acktarget" />
</route>
<route>
<from uri="direct:acktarget" />
<log message="acktarget: isEven property is :: ${property[isEven]}" />
</route>
Output:
exchange.getExchangeId() = ID-pis-iMac-local-54434-1393006139076-0-3
********** Exchange Id lastDigit 3 isEven: false ***********
[ main] route1 INFO isEven property is :: false
[ main] route2 INFO acktarget: isEven property is :: false
exchange.getExchangeId() = ID-pis-iMac-local-54434-1393006139076-0-4
********** Exchange Id lastDigit 4 isEven: true ***********
[ main] route1 INFO isEven property is :: true
[ main] route2 INFO acktarget: isEven property is :: true
exchange.getExchangeId() = ID-pis-iMac-local-54434-1393006139076-0-5
********** Exchange Id lastDigit 5 isEven: false ***********
[ main] route1 INFO isEven property is :: false
[ main] route2 INFO acktarget: isEven property is :: false
Even if I invoke a bean before forwarding the message to the other route, the property is kept. So, I guess your problems is in <to uri="bean:hl7handler?method=handleORM" />. Try to log the property before invoking this bean and see if the property is still set. If not, have a look at the bean.

Answer 2

For newer version of apache camel use exchangeProperty instead of property
${exchangeProperty.isEven}
The simple language property function was deprecated in Camel 2.x and has been removed. Use exchangeProperty as function name.

Answer 3

You do not need to use quotes. Try just
<simple>${property.isEven} == true</simple>