jcustenborder#115 Skip over null values in PatternMapString

Author: developster

src/main/java/com/github/jcustenborder/kafka/connect/transform/common/PatternMapString.java

@@ -109,6 +109,8 @@ protected SchemaAndValue processStruct(R record, Schema inputSchema, Struct inpu
         }
         outputStruct.put(config.destfieldname, replacedValue);
         retVal = new SchemaAndValue(outPutSchema, outputStruct);
+      } else {
+        retVal = new SchemaAndValue(outPutSchema, inputStruct);
       }
     }
     return retVal;