Null Argument treated as no parameter during method selection

[Ankit Bakshi]

Hi,

I am trying to call Apaches' StringUtils class from my spring XML route file.
I got to with the following code.

<bean id="ExtnFieldServ" 
class="com.ericsson.tcrm.bil.customizations.util.ExtendedFieldManagerRouteBean" 
/> <!-just for reference-->

<choice>
                <when>
                    <simple>
                        
${bean:org.apache.commons.lang.StringUtils?method=isNotEmpty(${bean:ExtnFieldServ?method=getFieldValueFromExchange(*,in.header.PA_CONTEXT,PaymentMethod)})}
                    </simple>
<!-stuff happens here-->
</when>
</ choice>

This worked fine when bean:ExtnFieldServ?method=getFieldValueFromExchange 
returned a non-null value. But failed with null.
Got the following exception

org.apache.camel.component.bean.MethodNotFoundException: Method with name: 
isNotEmpty() (with no parameters) not found on bean: 
org.apache.commons.lang.StringUtils@3030debe of type: 
org.apache.commons.lang.StringUtils. Exchange[Message: 
com.ericsson.etelcrm.bil.common.exec.SessionContext@1bec93f]

So basically camel was looking for a no parameter method when the actual 
argument evaluated to null. This is very strange. I don't know if this is 
normal behavior or a bug.

So I had to think of another way to get the code to work. A couple of 
workarounds would work. One of which is posted below.

<setProperty propertyName="CC_TMP_PAYMM">
                <simple>
                        
${bean:ExtnFieldServ?method=getFieldValueFromExchange(*,in.header.PA_CONTEXT,PaymentMethod)}
                </simple>
            </setProperty>
            <choice>
                <when>
                    <simple>
                        
${bean:org.apache.commons.lang.StringUtils?method=isNotEmpty(property.CC_TMP_PAYMM)}
                    </simple>
<!-stuff happens here-->
</when>
</ choice>

I went with property, the same approach can be taken with headers. Or I can 
create wrapper class around StringUtils which will have methods like below, and 
I would need to declare this wrapper as spring bean or use directly if I can 
using statics.

public boolean isNotBlank()
    {
        return isNotBlank(null);
    }

    public boolean isEmpty(String value)
    {
        return org.apache.commons.lang.StringUtils.isEmpty(value);
    }

What I really wanna know if why Camel is looking for  a no parameter method 
when the parameter expression evaluates to null?

Regards,
Ankit Bakshi