I was able to figure it out, and get it to work..

Class osuwmc.DataLookup.REST.TableLookup Extends osuwmc.DataLookup.REST.Base
{

Parameter Version = "1.0.0";Parameter HandleCorsRequests = 0;

XData UrlMap [ XMLNamespace = "http://www.intersystems.com/urlmap" ]
{
<Routes> 
    <!-- Server Info -->
    <Route Url="/" Method="GET" Call="GetInfo" />
    <Route Url="/EpicDepartment" Method="GET" Call="GetAllEpicDepartments" />
    <Route Url="/EpicDepartment/:departmentID" Method="GET" Call="GetEpicDepartment"/>
    </Routes>
}

ClassMethod GetInfo() As%Status
{
    SET version = ..#Version
    SET info = {
      "version": (version)
    }
    RETURN ..%ProcessResult($$$OK, info)
}

ClassMethod GetAllEpicDepartments() As%Status
{
    SET tSC = $$$OKset%response.ContentType = ..#CONTENTTYPEJSON
    set rset = ##class(osuwmc.Epic.Clarity.DepartmentMaster).ExtentFunc()
    write"["if rset.%Next(){
      set department = ##class(osuwmc.Epic.Clarity.DepartmentMaster).%OpenId(rset.ID1)
      do department.%JSONExport()
    }
    while rset.%Next(){
      write","set department = ##class(osuwmc.Epic.Clarity.DepartmentMaster).%OpenId(rset.ID1)
      do department.%JSONExport()
    }
    write"]"quit tSC
}

ClassMethod GetEpicDepartment(departmentID As%String) As%Status
{
  #dim tSC as%Status = $$$OK#dim e As%Exception.AbstractException#dim id as%Integerset%response.ContentType = ..#CONTENTTYPEJSON
  &sql(SELECT ID1 INTO :idFROM osuwmc_Epic_Clarity.DepartmentMaster WHEREID = :departmentID)
  IF SQLCODE<0 {WRITE"SQLCODE error ",SQLCODE," ",%msgQUIT}
  ELSEIF SQLCODE=100 {WRITE"Query returns no results"QUIT}
  set department = ##class(osuwmc.Epic.Clarity.DepartmentMaster).%OpenId(id)
  Do department.%JSONExport()
  QUIT tSC
}

ClassMethod SwaggerSpec() As%Status
{
  Set tSC = ##class(%REST.API).GetWebRESTApplication($NAMESPACE, %request.Application, .swagger)
  Do swagger.info.%Remove("x-ISC_Namespace")
  Set swagger.basePath = "/api/mgmnt/v1/TESTCLIN/spec/TableLookup"Set swagger.info.title = "REST API to Access and Query OSUWMC Cache Tables"Set swagger.info.version = "0.1"Set swagger.host = "intengtest"Return ..%ProcessResult($$$OK, swagger)
}

}

That helped. I was able to get my first two Method's called; however, I am struggling now with passing a value into the message.

<Routes><!-- Server Info --><RouteUrl="/"Method="GET"Call="GetInfo" /><RouteUrl="/GetAllEpicDepartments"Method="GET"Call="GetAllEpicDepartments" /><RouteUrl="/GetEpicDepartment"Method="GET"Call="GetEpicDepartment" /></Routes>

ClassMethod GetEpicDepartment(ID As%String) As%Status
{
    SET tSC = $$$OKset sql = "SELECT ID as DepartmentID, Abbr, Name, ExternalName, PhoneNumber, ApptPhone, FaxNumber, Address1, Address2, City, Zip, Specialty, RevLocID, RevLocName, BuildingCategoryID, BuildingName, DepCategoryTypeID, DepType, Center, EAFParent, CostCenter FROM osuwmc_Epic_Clarity.DepartmentMaster WHERE ID = ?"do##class(%ZEN.Auxiliary.jsonSQLProvider).%WriteJSONFromSQL(,,sql,ID)
    return tSC
}

When I try to pass... https://intengtest/api/mgmnt/v1/TESTCLIN/spec/TableLookup/GetEpicDepartment/{ID} into postman I get the following...

{
    "errors": [
        {
            "code": 5002,
            "domain": "%ObjectErrors",
            "error": "ERROR #5002: ObjectScript error: <REGULAR EXPRESSION>PatternSet+4^%Regex.Matcher.1",
            "id": "ObjectScriptError",
            "params": [
                "&lt;REGULAR EXPRESSION&gt;PatternSet+4^%Regex.Matcher.1"
            ]
        }
    ],
    "summary": "ERROR #5002: ObjectScript error: &lt;REGULAR EXPRESSION&gt;PatternSet+4^%Regex.Matcher.1"
}

Stay Connected is set at 60, messages are sent to the BO in batches depending on when we receive the HL7 message that it requires a lookup. 

Because this is going through a Java Gateway Business Service it seems like there is a disconnect on when the BO loses connection and pipe that it uses through the Java Gateway Business Service. The BO loses the connection, but the Java Gateway Business Service still thinks it is connected to the Database.

I have tried adding Connection Attributes to the BO, but it has not help.

Business Operation Settings

<ItemName="PatientBillingDBPoll"Category="PatientBilling,SQL,PROD,CC,VANW,PatFeeder"ClassName="osuwmc.PatientBilling.PatientBillingDBPollOperation"PoolSize="1"Enabled="true"Foreground="false"Comment="Is used to lookup items against clarity tables"LogTraceEvents="true"Schedule=""><SettingTarget="Adapter"Name="Credentials"></Setting><SettingTarget="Adapter"Name="DSN">MS-PatientBilling</Setting><SettingTarget="Adapter"Name="JGService">PatientBilling.JavaGateway</Setting><SettingTarget="Host"Name="FailureTimeout">20</Setting><SettingTarget="Host"Name="ReplyCodeActions">E=R</Setting><SettingTarget="Host"Name="AlertOnError">0</Setting><SettingTarget="Adapter"Name="StayConnected">60</Setting><SettingTarget="Adapter"Name="ConnectionAttributes">"queryTimeout = 30";"socketTimeout = 60";"cancelQueryTimeout = 45";"connectRetryCount = 100";"connectRetryInterval = 5"</Setting><SettingTarget="Host"Name="ArchiveIO">1</Setting></Item>

Java Gateway Settings

<ItemName="PatientBilling.JavaGateway"Category="PROD"ClassName="EnsLib.JavaGateway.Service"PoolSize="1"Enabled="true"Foreground="false"Comment=""LogTraceEvents="true"Schedule=""><SettingTarget="Host"Name="Port">55558</Setting><SettingTarget="Host"Name="JavaHome">/usr</Setting><SettingTarget="Host"Name="Logfile"></Setting><SettingTarget="Host"Name="ClassPath">/nfs/data/drivers/java/*</Setting><SettingTarget="Host"Name="JVMArgs">-d64 -Xss512k -Xmx1024m -XX:+DisableExplicitGC -XX:+AggressiveOpts -XX:+ExplicitGCInvokesConcurrent -XX:+UseStringDeduplication -XX:MaxHeapFreeRatio=10 -XX:MinHeapFreeRatio=5</Setting></Item>