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deftypeddispatch
(ns cheshire.generate
(:use [cheshire.type-dispatch :only [deftypedispatched defdispatched]])
(:import (org.codehaus.jackson JsonGenerator)
(java.util List Date SimpleTimeZone UUID)
(java.text SimpleDateFormat)
(clojure.lang IPersistentCollection Keyword Symbol IPersistentMap
IPersistentVector IPersistentSet ISeq)))
(set! *warn-on-reflection* true)
(definline write-string [jg str]
`(let [^JsonGenerator jg# ~jg
^String str# ~str]
(.writeString jg# str#)))
(definline fail [obj & _]
`(throw (Exception. (str "Cannot generate " ~obj))))
(declare generate)
(deftypedispatched generate*)
(defdispatched generate* :miss [obj ^JsonGenerator jg _]
`(if (nil? ~obj)
(.writeNull ~jg)
(fail ~obj)))
(deftypedispatched generate-coll)
(defdispatched generate-coll IPersistentMap [obj ^JsonGenerator jg date-format]
`(do
(.writeStartObject ~jg)
(doseq [[k# v#] ~obj
:let [field-name# (if (keyword? k#)
(name k#)
(str k#))]]
(.writeFieldName ~jg field-name#)
(generate ~jg v# ~date-format))
(.writeEndObject ~jg)))
(defdispatched generate-coll IPersistentVector [obj ^JsonGenerator jg
date-format]
`(do
(.writeStartArray ~jg)
(dotimes [i# (count ~obj)]
(let [^List x# ~obj]
(generate ~jg (.get x# i#) ~date-format)))
(.writeEndArray ~jg)))
(defdispatched generate-coll IPersistentSet [obj ^JsonGenerator jg date-format]
`(generate ~jg (seq ~obj) ~date-format))
(defdispatched generate-coll ISeq [obj ^JsonGenerator jg date-format]
`(do
(.writeStartArray ~jg)
(doseq [item# ~obj]
(generate ~jg item# ~date-format))
(.writeEndArray ~jg)))
(defdispatched generate* IPersistentCollection [obj ^JsonGenerator jg
date-format]
`(generate-coll ~obj ~jg ~date-format))
(deftypedispatched generate-number)
(defdispatched generate-number :miss [obj jg]
`(fail ~obj))
(defdispatched generate-number Integer [obj ^JsonGenerator jg]
`(.writeNumber ~jg ~obj))
(defdispatched generate-number Long [obj ^JsonGenerator jg]
`(.writeNumber ~jg ~obj))
(defdispatched generate-number Float [obj ^JsonGenerator jg]
`(.writeNumber ~jg ~obj))
(defdispatched generate-number Double [obj ^JsonGenerator jg]
`(.writeNumber ~jg ~obj))
(defdispatched generate-number BigInteger [obj ^JsonGenerator jg]
`(.writeNumber ~jg ~obj))
(defdispatched generate* Number [obj ^JsonGenerator jg date-format]
`(generate-number ~obj ~jg))
(defdispatched generate* String [obj jg date-format]
`(write-string ~jg ~obj))
(defdispatched generate* Keyword [obj jg date-format]
`(write-string ~jg (name ~obj)))
(defdispatched generate* UUID [obj jg date-format]
`(write-string ~jg (.toString ~obj)))
(defdispatched generate* Symbol [obj jg date-format]
`(write-string ~jg (.toString ~obj)))
(defdispatched generate* Boolean [obj jg date-format]
`(let [^JsonGenerator jg# ~jg]
(.writeBoolean jg# ~obj)))
(defdispatched generate* Date [obj jg date-format]
`(let [sdf# (doto (SimpleDateFormat. ~date-format)
(.setTimeZone (SimpleTimeZone. 0 "UTC")))]
(write-string ~jg (.format sdf# ~obj))))
(defn generate [^JsonGenerator jg obj date-format]
(generate* obj jg date-format))
;; the above all inlines into something like(infact even more stuff is
;; inlined into the below):
(comment
(defn generate [^JsonGenerator jg ^Object obj ^String date-format]
(condp instance? obj
IPersistentCollection (condp instance? obj
clojure.lang.IPersistentMap
(do
(.writeStartObject jg)
(doseq [[k v] obj
:let [field-name (if (keyword? k)
(name k)
(str k))]]
(.writeFieldName jg field-name)
(generate jg v date-format))
(.writeEndObject jg))
clojure.lang.IPersistentVector
(do
(.writeStartArray jg)
(dotimes [i (count obj)]
(generate jg (.get ^List obj i) date-format))
(.writeEndArray jg))
clojure.lang.IPersistentSet
(generate jg (seq obj) date-format)
clojure.lang.ISeq
(do
(.writeStartArray jg)
(doseq [item obj]
(generate jg item date-format))
(.writeEndArray jg)))
Number (condp instance? obj
Integer (.writeNumber jg ^Integer obj)
Long (.writeNumber jg ^Long obj)
Float (.writeNumber jg ^Float obj)
Double (.writeNumber jg ^Double obj)
BigInteger (.writeNumber jg ^BigInteger obj)
(fail obj))
String (write-string jg ^String obj)
Keyword (write-string jg (name obj))
UUID (write-string jg (.toString obj))
Symbol (write-string jg (.toString obj))
Boolean (.writeBoolean jg ^Boolean obj)
Date (let [sdf (doto (SimpleDateFormat. date-format)
(.setTimeZone (SimpleTimeZone. 0 "UTC")))]
(write-string jg (.format sdf obj)))
(if (nil? obj)
(.writeNull jg)
(fail obj)))))
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