Data weave : Remove duplicate record set based on one record set field's value

Question

I need to filter the response with respect to DSUltimateId. Following is the error that I am getting while testing the same.

ERROR 2017-08-28 16:34:13,669 [[esb-domain].HTTPS_EIP_Listener_Configuration.worker.01] org.mule.exception.CatchMessagingExceptionStrategy: 
********************************************************************************
Message               : Exception while executing: 
            (ns0#DSUltimateId: $.ns01#stringValue  ) when $.ns01#name == "IU_ROWID" distinctBy $ ,
                                                               ^
Cannot coerce a :array to a :boolean
Type                  : com.mulesoft.weave.mule.exception.WeaveExecutionException
Code                  : MULE_ERROR--2

Here is my data weave code: where I am trying to filter out the duplicate records based on on "DSUltimateID" **which might occur multiple times.

%dw 1.0
%output application/xml
%output application/xml inlineCloseOn = "empty"
%output application/xml skipNullOn="attributes"
%namespace ns0 http://www.example.org/IUGetMasterOrganizationRecordByIdOrName
%namespace ns01 urn:siperian.api
---
ns0#CustomerMasterDataDSUltimateResponse: {
    ns0#DSUltimate: {
        (payload.ns01#searchQueryReturn.*ns01#record.*ns01#field map
                              {

            (ns0#ElectronicAddressTypeCd: $.ns01#stringValue ) when $.ns01#name == "EADDR_TYPE_CD" and  ($.ns0#stringValue != ("" and null)),
            (ns0#ElectronicAddressTxt: $.ns01#stringValue ) when $.ns01#name == "EADDR_TXT" and $.ns0#stringValue != ("" or null),
            (ns0#DSUltimateId: $.ns01#stringValue  ) when $.ns01#name == "IU_ROWID" distinctBy $ ,
            (ns0#DSUltimateNm : $.ns01#stringValue) when $.ns01#name == "IU_NM",
            (ns0#DSUltimateClassificationCd : $.ns01#stringValue) when $.ns01#name == "IU_CLASS_CODE",
            (ns0#ApprovalStatusDSUltimateRequesterId : $.ns01#stringValue) when $.ns01#name == "APRV_STS_IU_RQSTR_ID",
            (ns0#DSUltimateCreateReasonCd : $.ns01#stringValue) when $.ns01#name == "IU_CRE_RSN_CD",
            (ns0#DSUltimateApprovalStatusCd : $.ns01#stringValue) when $.ns01#name == "IU_APRV_STS_CD",
            (ns0#DSUltimateEffectiveStartDtm : $.ns01#dateValue) when $.ns01#name == "EFF_STRT_DTM",
            (ns0#DSUltimateEffectiveEndDtm : $.ns01#dateValue !=null) when $.ns01#name == "EFF_END_DTM"
        }
            ) 
    }
}

here is my sample input

Answer 1

     %dw 1.0
 %output application/xml inlineCloseOn = "empty" ,skipNullOn="attributes"
 %namespace ns0 http://www.example.org/IUGetMasterOrganizationRecordByIdOrName
 %namespace ns01 urn:siperian.api
 ---
 {CustomerMasterDataDSUltimateResponse :   {((payload.ns01#searchQueryReturn.*ns01#record  map
          DSUltimate:   {
          (  $.*field map {
          (ElectronicAddressTypeCd: $.ns01#stringValue ) when $.ns01#name == "EADDR_TYPE_CD" and  $.ns01#stringValue !=  null and $.ns01#stringValue != "",
          (ElectronicAddressTxt: $.ns01#stringValue ) when $.ns01#name == "EADDR_TXT" and   $.ns01#stringValue != null and $.ns01#stringValue != "",
          (DSUltimateId: trim $.ns01#stringValue) when $.ns01#name == "IU_ROWID",
          (DSUltimateNm : $.ns01#stringValue) when $.ns01#name == "IU_NM",
          (DSUltimateClassificationCd : $.ns01#stringValue) when $.ns01#name == "IU_CLASS_CODE",
          (ApprovalStatusDSUltimateRequesterId : $.ns01#stringValue) when $.ns01#name == "APRV_STS_IU_RQSTR_ID",
          (DSUltimateCreateReasonCd : $.ns01#stringValue) when $.ns01#name == "IU_CRE_RSN_CD",
          (DSUltimateApprovalStatusCd : $.ns01#stringValue) when $.ns01#name == "IU_APRV_STS_CD",
          (DSUltimateEffectiveStartDtm : $.ns01#dateValue) when $.ns01#name == "EFF_STRT_DTM",
          (DSUltimateEffectiveEndDtm : $.ns01#dateValue) when $.ns01#name == "EFF_END_DTM"  and  $.ns01#stringValue !=  null and $.ns01#stringValue != ""
          }  
        )
      }
     ) distinctBy  $.DSUltimate.DSUltimateId )}}

Answer 2

You are usingdistinctBy while mapping but it should be used after mapping. Please refer answer here