Retrieves an instances of the domain class for the specified ids and returns a list of these instances, ordered by the original ids list. If some of provided ids are null or there are no instances with these ids, then result list will contain null values on corresponding positions.
// get a list which contains Book instances with ids 2, 1, 3 respectively
def bookList = Book.getAll(2, 1, 3)// can take a list of ids as only argument, very
// useful when the ids list is calculated in code
def bookList = Book.getAll([1, 2, 3])// when called without arguments returns list of all objects
def bookList = Book.getAll()
varargs* - A variable argument list of ids
ids* - A list of ids