Setting multiple headers in camel route - apache-camel

Question

Is it possible to set multiple exchange headers in camel route using single call to setHeader.
Something like this
<from uri="file://inputdir/?delete=true" />
<!-- need to set multiple headers at once(as a comma separated list)-->
<setHeader headerName="headername">
<constant>headerval</constant>
</setHeader>
<to uri="mock:end"/>
Or should I create a custom processor for this?

Answer 1

No you cant set multiple headers at once as far as I am aware. In your case a custom processor will probably be more effective.
You might want to look at the simple expression language here here is that you can OGNL notation in your camel route xml file. OGNL will allow you to specify a chain of methods in the expression.
For example suppose you have a message that contains an Employee object that has a getSalaryGrade() method you could set a header to this value by using the following syntax:
<setHeader headerName="SalaryGrade">
<simple>${body.getSalaryGrade()}</simple>
</setHeader>
You could for example create a simple class that returns a list and store the list in the header and then access the list via simple in the route. The following code is untested but should give you a idea.
public class ListCity {
public List<String> ListCities()
{
ArrayList< String> list = new ArrayList<String>();
list.add("New York");
list.add("JOhannesburg");
list.add("HoChiMinh");
return list;
}
}
Declare the list city bean in your xml. You can then set this list into a header by using something like this:
<setHeader headerName="CityList">
<simple>${listCity.ListCities()}</simple>
</setHeader>