Java - List of operation executor

For a REST API request, I parse the JSON to get a List of recipes.

Each recipe involves multiple fields that need to be resolved to a value using different types of operations. Each field value is generated by an operation like querying DB, external REST calls, sequence number generation. A post operation will be performed on the generated value.

For example, one recipe can be

Field1+Field2+Field3

Field1 => resolved by DB operation. Then do list of post operations which would be java String manipulation. Field2 => Invoke REST call. Then do list of post operations which would be java String manipulation. Field3, to be resolved after field1 and field2 => Invoke sequence number generation based on field1 value and field2 value

I would like to derive the list of operations from the JSON and execute them in a generic way irrespective of the format of incoming JSON. Other JSON with completely different JSON would also be parsed to invoke same set of operations.

   abstract class Operation {
      factoryCreationMethod(operationType) {
        if (operationType.equals(DB)) {
           return new DbOperation();
        }
      }

      public final doOperationTemplate() {
         populateOperation(Map<String, Object>);
         PerformOperation();
         performPostOp(Ordered<String, String>);    
         // postops would be trim n chars from beg or end
      } 
   }
   Class DbOperation extends Operation {
     String query = null;
     SimpleBindings params = null;
     @Override
     populateOperation(Map<String, Object> listObjs) {
     // perform op specific init
     }
    // implement performOperation and performPostOp

   }

   class genericRestTemplate extends Operation {
   }

What is the best way to design this list of generic operations and post operations? At this moment, I'm going to perform operations sequentially.