How to do addition of two numbers in wso2esb - xpath

Question

I am using wso2esb4.7.0
i wish to do addition of 2 numbers using wso2esb for that i have written my proxy but its not working
my proxy is like this
<?xml version="1.0" encoding="UTF-8"?>
<proxy xmlns="http://ws.apache.org/ns/synapse"
name="Addition"
transports="https,http"
statistics="disable"
trace="disable"
startOnLoad="true">
<target>
<inSequence>
<property name="Value1"
expression="//Value1/text()"
scope="default"
type="STRING"/>
<property name="Value2"
expression="//Value2/text()"
scope="default"
type="STRING"/>
<property name="Result"
expression="fn:sum(get-property('Value1'),get-property('Value2'))"
scope="default"
type="STRING"/>
<log>
<property name="RESULT" expression="get-property('Result')"/>
</log>
</inSequence>
<outSequence/>
</target>
<description/>
</proxy>
i logged it the result is given errors :
ERROR - SynapseXPath Evaluation of the XPath expression fn:sum(get-property('Value1'),get-property('Value2')) resulted in an error
org.jaxen.FunctionCallException: sum() requires one argument.
at org.jaxen.function.SumFunction.call(SumFunction.java:99)
at org.jaxen.expr.DefaultFunctionCallExpr.evaluate(DefaultFunctionCallExpr.java:177)
at org.jaxen.expr.DefaultXPathExpr.asList(DefaultXPathExpr.java:102)
at org.jaxen.BaseXPath.selectNodesForContext(BaseXPath.java:674)
at org.jaxen.BaseXPath.selectNodes(BaseXPath.java:213)
at org.jaxen.BaseXPath.evaluate(BaseXPath.java:172)
and I tried with this also
<property name="Result"
expression="fn:sum(//Value1/text(),//Value2/text()))"
scope="default"
type="STRING"/>
Even this is also giving errors how would i reach to addition goal and my curl command like this
curl -v -H "Accept: application/json" -H "Content-Type:application/json" -H "ModifiedOn:0" -H "userid:-1899999899" -H "username:vikash|214057357158656" -H "password:gbadmin" -d '{"Value1":"2","Value2":"45"}' http://youtility2-desktop:8282/services/Addition

Answer 1

You can use the script mediator to achieve this. First you can set the two values as you have done above. Then in the script mediator you can add them and set to the required property.
Complete proxy with this approach;
<?xml version="1.0" encoding="UTF-8"?>
<proxy xmlns="http://ws.apache.org/ns/synapse"
name="Addition"
transports="https,http"
statistics="disable"
trace="disable"
startOnLoad="true">
<target>
<inSequence>
<property name="Value1"
expression="//Value1/text()"
scope="default"
type="INTEGER"/>
<property name="Value2"
expression="//Value2/text()"
scope="default"
type="INTEGER"/>
<script language="js">
var value1 = mc.getProperty("Value1");
var value2 = mc.getProperty("Value2");
var result = value1 + value2;
mc.setProperty("Result", result);
</script>
<log>
<property name="RESULT" expression="get-property('Result')"/>
</log>
</inSequence>
<outSequence/>
</target>
<description/>
</proxy>

Answer 2

<?xml version="1.0" encoding="UTF-8"?>
<proxy xmlns="http://ws.apache.org/ns/synapse"
name="Addition"
transports="https,http"
statistics="disable"
trace="disable"
startOnLoad="true">
<target>
<inSequence>
<property name="Value1"
expression="//Value1/text()"
scope="default"
type="INTEGER"/>
<property name="Value2"
expression="//Value2/text()"
scope="default"
type="INTEGER"/>
<script language="js">
var value1 = parseInt(mc.getProperty("Value1"));
var value2 = parseInt(mc.getProperty("Value2"));
var result = value1 + value2;
mc.setProperty("Result", result);
</script>
<log>
<property name="RESULT" expression="get-property('Result')"/>
</log>
</inSequence>
<outSequence/>
</target>
<description/>
</proxy>