Xpath conditioning in datamapper using rule - xpath

Question

If the below XML is evaluated using datamapper to map only even numbered id's to output then the condition using xpath(Rule) is : ?
<employees>
<employee>
<id>1</id>
<name>aaa</name>
</employee>
<employee>
<id>2</id>
<name>bbb</name>
</employee>
<employee>
<id>3</id>
<name>ccc</name>
</employee>
<employee>
<id>4</id>
<name>ddd</name>
</employee>
</employees>
I tried using /employee[id mod 2 = 0]/id. It maps if the input has only one even number and fails if it has more than one even numbered id in the input.xml.
The error is
Result of xpath filling field 'id' contains two or more values!

Answer 1

Rules are independent to each Element Mapping configured in DM. Rules are to be created in the element mapping configuration it is intended to be used in.
For the sample xml provided, this rule should be created in Foreach 'employee' -> 'employee' element mapping.
Try this for the rule configuration
Name : {Rule Name}
Type : Boolean
Context : /employees/employee
Xpath : /matches(string(id mod 2), '0')
This creates a rule returning true if id is even and false if id is odd.
Use an if block in DM script view and check for the rule's value. if rule value is true, only then map the id.

Answer 2

It also worked in this way
Name : {Rule Name}
Type : String
Context : /employees/employee
Xpath : /id mod 2 = 0
and used the if condition as below :
if(input.Ruleid.equals("true")){
output.id = input.id;
output.name = input.name;
}
Is there any other way to do this without using if condition.