(Quick Reference)
                findOrSaveWhere
Purpose
Uses named arguments corresponding to property names of the domain class to execute a query returning the first matching result. This method behaves just like 
findWhere except that it will never return 
null. If a matching instance cannot be found in the database then a new instance is created, populated with values from the query parameters, saved and returned.  The difference between this method and 
findOrCreateWhere is that this method will save a newly created instance where 
findOrCreateWhere does not.
Examples
Given the domain class:
class Book {   String title
   Date releaseDate
   String author   static constraints = {
      releaseDate nullable: true
   }
}You can query in the form:
def book = Book.findOrSaveWhere(author: "Stephen King", title: "The Stand")
Description
Parameters:
- queryParams- A Map of key/value pairs to be used in the query. If no matching instance is found then this data is used to initialize a new instance.