forEach loop in BPEL (WSO2 BPS) - wso2

Question

I am not able to figure out the root cause for the problem, why the forEach loop is not working,
<bpel:forEach name="eachMarket" parallel="no" counterName="marketCounter">
<bpel:startCounterValue>1</bpel:startCounterValue>
<bpel:finalCounterValue>count($input.payload/tns:DCTResponse/tns:DCTIDs/tns:DCTID)</bpel:finalCounterValue>
<bpel:scope>
<bpel:assign>
<bpel:copy ignoreMissingFromData="yes" insertMissingToData="yes">
<bpel:from>$input.payload/tns:DCTResponse/tns:DCTIDs/tns:DCTID[round($marketCounter)]/tns:DEFTYPE</bpel:from>
<bpel:to>$OrderParameterPLRequest.parameters/ns:DCTResponse/ns:DCTIDs/ns:DCTID[round($marketCounter)]/ns:DEFTYPE</bpel:to>
</bpel:copy>
<bpel:copy ignoreMissingFromData="yes" insertMissingToData="yes">
<bpel:from>$input.payload/tns:DCTResponse/tns:DCTIDs/tns:DCTID[round($marketCounter)]/tns:MarketName</bpel:from>
<bpel:to>$OrderParameterPLRequest.parameters/ns:DCTResponse/ns:DCTIDs/ns:DCTID[round($marketCounter)]/ns:MarketName</bpel:to>
</bpel:copy>
<bpel:copy ignoreMissingFromData="yes" insertMissingToData="yes">
<bpel:from>$input.payload/tns:DCTResponse/tns:DCTIDs/tns:DCTID[round($marketCounter)]/tns:DCTID</bpel:from>
<bpel:to>$OrderParameterPLRequest.parameters/ns:DCTResponse/ns:DCTIDs/ns:DCTID[round($marketCounter)]/ns:DCTID</bpel:to>
</bpel:copy>
</bpel:assign>
</bpel:scope>
</bpel:forEach>
<bpel:forEach name="eachParameter" parallel="no" counterName="parameterCounter">
<bpel:startCounterValue>1</bpel:startCounterValue>
<bpel:finalCounterValue>count($input.payload/tns:DCTResponse/tns:AdditionalParamters/tns:Parameter)</bpel:finalCounterValue>
<bpel:scope name="parameterScope">
<bpel:assign>
<bpel:copy ignoreMissingFromData="yes" insertMissingToData="yes">
<bpel:from>$input.payload/tns:DCTResponse/tns:AdditionalParamters/tns:Parameter[$parameterCounter]/tns:Name</bpel:from>
<bpel:to>$OrderParameterPLRequest.parameters/ns:DCTResponse/ns:AdditionalParamters/ns:Parameter[$parameterCounter]/ns:Name</bpel:to>
</bpel:copy>
<bpel:copy ignoreMissingFromData="yes" insertMissingToData="yes">
<bpel:from>$input.payload/tns:DCTResponse/tns:AdditionalParamters/tns:Parameter[$parameterCounter]/tns:Value</bpel:from>
<bpel:to>$OrderParameterPLRequest.parameters/ns:DCTResponse/ns:AdditionalParamters/ns:Parameter[$parameterCounter]/ns:Value</bpel:to>
</bpel:copy>
</bpel:assign>
</bpel:scope>
</bpel:forEach>
Input will contain multiple Ids,
<p:DCTIDs>
<p:DCTID>
<p:DEFTYPE>acvinclis</p:DEFTYPE>
<p:MarketName>pectoreflammas</p:MarketName>
<p:DCTID>3</p:DCTID>
</p:DCTID>
<p:DCTID>
<p:DEFTYPE>acvinclis</p:DEFTYPE>
<p:MarketName>pectoreflammas</p:MarketName>
<p:DCTID>3</p:DCTID>
</p:DCTID>
<p:DCTID>
<p:DEFTYPE>acvinclis</p:DEFTYPE>
<p:MarketName>pectoreflammas</p:MarketName>
<p:DCTID>3</p:DCTID>
</p:DCTID>
</p:DCTIDs>
Error message:
faultExplanation={http://docs.oasis-open.org/wsbpel/2.0/process/executable}selectionFailure: No results for expression: '$OrderParameterPLRequest.parameters/ns:DCTResponse/ns:DCTIDs/ns:DCTID[round($marketCounter)]/ns:DEFTYPE' against '

Answer 1

This question is probably not relevant for the original poster anymore, but I wanted to include an answer in case anybody else has the same problem.
If you want to get the DEFTYPE of the DCTID at position $Counter, use the following XPath:
($input.payload/tns:DCTResponse/tns:DCTIDs/tns:DCTID)[position() = $Counter]/tns:DEFTYPE
Two things are important here:
Put parentheses around the entire expression up to DTCID. For the reason why, see https://stackoverflow.com/a/8336922/5986352
While [1], [2], etc. will work, [$Counter] will not work. Instead, use [position() = $Counter]. You can also use position() to perform some more complex queries, e.g., [position() < 3] in order to select the first two nodes from a certain set.