Back
as-maps-adapter (clj)
(source)function
(as-maps-adapter builder-fn column-reader)
Given a map builder function (e.g., `as-lower-maps`) and a column reading
function, return a new builder function that uses that column reading
function instead of `.getObject` so you can override the default behavior.
This adapter omits SQL NULL values, even if the underlying builder does not.
The default column-reader behavior would be equivalent to:
(defn default-column-reader
[^ResultSet rs ^ResultSetMetaData rsmeta ^Integer i]
(.getObject rs i))
Your column-reader can use the result set metadata to determine whether
to call `.getObject` or some other method to read the column's value.
`read-column-by-index` is still called on the result of that read, if
it is not `nil`.
Examples
next-jdbc
(ns next.jdbc.optional-test
"Test namespace for the optional builder functions."
(:require [clojure.string :as str]
[clojure.test :refer [deftest is testing use-fixtures]]
[next.jdbc.optional :as opt]
[next.jdbc.protocols :as p]
[next.jdbc.test-fixtures :refer [with-test-db ds column
default-options]])
(:import (java.sql ResultSet ResultSetMetaData)))
(deftest test-map-row-adapter
(testing "default row builder"
(let [row (p/-execute-one (ds)
["select * from fruit where id = ?" 1]
(assoc (default-options)
:builder-fn (opt/as-maps-adapter
opt/as-maps
default-column-reader)))]
(is (map? row))
(is (not (contains? row (column :FRUIT/GRADE))))
(is (= 1 ((column :FRUIT/ID) row)))
(is (= "Apple" ((column :FRUIT/NAME) row)))))
(testing "unqualified row builder"
(let [row (p/-execute-one (ds)
["select * from fruit where id = ?" 2]
{:builder-fn (opt/as-maps-adapter
opt/as-unqualified-maps
default-column-reader)})]
(is (map? row))
(is (not (contains? row (column :COST))))
(is (= 2 ((column :ID) row)))
(is (= "Banana" ((column :NAME) row)))))
(testing "lower-case row builder"
(let [row (p/-execute-one (ds)
["select * from fruit where id = ?" 3]
(assoc (default-options)
:builder-fn (opt/as-maps-adapter
opt/as-lower-maps
default-column-reader)))]
(is (map? row))
(is (not (contains? row :fruit/appearance)))
(is (= 3 (:fruit/id row)))
(is (= "Peach" (:fruit/name row)))))
(testing "unqualified lower-case row builder"
(let [row (p/-execute-one (ds)
["select * from fruit where id = ?" 4]
{:builder-fn (opt/as-maps-adapter
opt/as-unqualified-lower-maps
default-column-reader)})]
(is (map? row))
(is (= 4 (:id row)))
(is (= "Orange" (:name row)))))
(testing "custom row builder"
(let [row (p/-execute-one (ds)
["select * from fruit where id = ?" 3]
(assoc (default-options)
:builder-fn (opt/as-maps-adapter
opt/as-modified-maps
default-column-reader)
:label-fn str/lower-case
:qualifier-fn identity))]
(is (map? row))
(is (not (contains? row (column :FRUIT/appearance))))
(is (= 3 ((column :FRUIT/id) row)))
(is (= "Peach" ((column :FRUIT/name) row))))))