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;; Copyright (c) Cosmin Stejerean. All rights reserved. The use and
;; distribution terms for this software are covered by the Eclipse Public
;; License 1.0 (http://opensource.org/licenses/eclipse-1.0.php) which can
;; be found in the file epl-v10.html at the root of this distribution. By
;; using this software in any fashion, you are agreeing to be bound by the
;; terms of this license. You must not remove this notice, or any other,
;; from this software.
(ns
^{:author "Cosmin Stejerean",
:doc "Support for recursively converting Java beans to Clojure and vice versa."}
clojure.java.data
(:use [clojure.tools.logging :only (info)]))
(def
^{:dynamic true,
:doc "Specify the behavior of missing setters in to-java in the
default object case, using one of :ignore, :log, :error"}
*to-java-object-missing-setter* :ignore)
(defmulti to-java (fn [destination-type value] [destination-type (class value)]))
(defmulti from-java class)
(defn- get-property-descriptors [clazz]
(.getPropertyDescriptors (java.beans.Introspector/getBeanInfo clazz)))
;; getters
(defn- is-getter [method]
(and method (= 0 (alength (. method (getParameterTypes))))))
(defn- make-getter-fn [method]
(fn [instance]
(from-java (.invoke method instance nil))))
(defn- add-getter-fn [the-map prop-descriptor]
(let [name (.getName prop-descriptor)
method (.getReadMethod prop-descriptor)]
(if (and (is-getter method) (not (= "class" name)))
(assoc the-map (keyword name) (make-getter-fn method))
the-map)))
;; setters
(defn- is-setter [method]
(and method (= 1 (alength (. method (getParameterTypes))))))
(defn- get-setter-type [method]
(get (.getParameterTypes method) 0))
(defn- make-setter-fn [method]
(fn [instance value]
(.invoke method instance (into-array [(to-java (get-setter-type method) value)]))))
(defn- add-setter-fn [the-map prop-descriptor]
(let [name (.getName prop-descriptor)
method (.getWriteMethod prop-descriptor)]
(if (is-setter method)
(assoc the-map (keyword name) (make-setter-fn method))
the-map)))
(defn- add-array-methods [acls]
(let [cls (.getComponentType acls)
to (fn [_ sequence] (into-array cls (map (partial to-java cls)
sequence)))
from (fn [obj] (map from-java obj))]
(.addMethod to-java [acls Iterable] to)
(.addMethod from-java acls from)
{:to to :from from}))
;; common to-java definitions
(defmethod to-java :default [^Class cls value]
(if (.isArray cls)
; no method for this array type yet
((:to (add-array-methods cls))
cls value)
value))
(defmethod to-java [Enum String] [enum value]
(.invoke (.getDeclaredMethod enum "valueOf" (into-array [String])) nil (into-array [value])))
(defn- throw-log-or-ignore-missing-setter [key clazz]
(let [message (str "Missing setter for " key " in " (.getCanonicalName clazz))]
(cond (= *to-java-object-missing-setter* :error)
(throw (new NoSuchFieldException message))
(= *to-java-object-missing-setter* :log)
(info message))))
(defmethod to-java [Object clojure.lang.APersistentMap] [clazz props]
"Convert a Clojure map to the specified class using reflection to set the properties"
(let [instance (.newInstance clazz)
setter-map (reduce add-setter-fn {} (get-property-descriptors clazz))]
(doseq [[key value] props]
(let [setter (get setter-map (keyword key))]
(if (nil? setter)
(throw-log-or-ignore-missing-setter key clazz)
(apply setter [instance value]))))
instance))
;; feature testing macro, based on suggestion from Chas Emerick:
(defmacro ^{:private true} when-available
[sym & body]
(try
(when (resolve sym)
(list* 'do body))
(catch ClassNotFoundException _#)))
(defmacro ^{:private true} when-not-available
[sym & body]
(try
(when-not (resolve sym)
(list* 'do body))
(catch ClassNotFoundException _#)))
(when-available
biginteger
(defmethod to-java [BigInteger Object] [_ value] (biginteger value)))
(when-not-available
biginteger
(defmethod to-java [BigInteger Object] [_ value] (bigint value)))
;; common from-java definitions
(defmethod from-java :default [^Object instance]
"Convert a Java object to a Clojure map"
(let [clazz (.getClass instance)]
(if (.isArray clazz)
((:from (add-array-methods clazz))
instance)
(let [getter-map (reduce add-getter-fn {} (get-property-descriptors clazz))]
(into {} (for [[key getter-fn] (seq getter-map)] [key (getter-fn instance)]))))))
(doseq [clazz [String Character Byte Short Integer Long Float Double Boolean BigInteger BigDecimal]]
(derive clazz ::do-not-convert))
(defmacro ^{:private true} defnumber [box prim prim-getter]
`(let [conv# (fn [_# number#]
(~(symbol (str box) "valueOf")
(. number# ~prim-getter)))]
(.addMethod to-java [~prim Number] conv#)
(.addMethod to-java [~box Number] conv#)))
(defmacro ^{:private true} defnumbers [& boxes]
(cons `do
(for [box boxes
:let [box-cls (resolve box)
prim-cls (.get (.getField box-cls "TYPE")
box-cls)
;; Clojure 1.3: (assert (class? box-cls) (str box ": no class found"))
_ (assert (class? box-cls))
;; Clojure 1.3: (assert (class? prim-cls) (str box " has no TYPE field"))
_ (assert (class? prim-cls))
prim-getter (symbol (str (.getName prim-cls) "Value"))]]
`(defnumber ~box ~(symbol (str box) "TYPE") ~prim-getter))))
(defnumbers Byte Short Integer Long Float Double)
(defmethod from-java ::do-not-convert [value] value)
(prefer-method from-java ::do-not-convert Object)
(defmethod from-java Iterable [instance] (for [each (seq instance)] (from-java each)))
(prefer-method from-java Iterable Object)
(defmethod from-java java.util.Map [instance] (into {} instance))
(prefer-method from-java java.util.Map Iterable)
(defmethod from-java nil [_] nil)
(defmethod from-java Enum [enum] (str enum))
;; definitions for interfacting with XMLGregorianCalendar
(defmethod to-java [javax.xml.datatype.XMLGregorianCalendar clojure.lang.APersistentMap] [clazz props]
"Create an XMLGregorianCalendar object given the following keys :year :month :day :hour :minute :second :timezone"
(let [instance (.newInstance clazz)
undefined javax.xml.datatype.DatatypeConstants/FIELD_UNDEFINED
getu #(get %1 %2 undefined)]
(doto instance
(.setYear (getu props :year))
(.setMonth (getu props :month))
(.setDay (getu props :day))
(.setHour (getu props :hour))
(.setMinute (getu props :minute))
(.setSecond (getu props :second))
(.setTimezone (getu props :timezone)))))
(defmethod from-java javax.xml.datatype.XMLGregorianCalendar [obj]
"Turn an XMLGregorianCalendar object into a clojure map of year, month, day, hour, minute, second and timezone "
(let [date {:year (.getYear obj)
:month (.getMonth obj)
:day (.getDay obj)}
time {:hour (.getHour obj)
:minute (.getMinute obj)
:second (.getSecond obj)}
tz {:timezone (.getTimezone obj)}
is-undefined? #(= javax.xml.datatype.DatatypeConstants/FIELD_UNDEFINED %1)]
(conj {}
(if-not (is-undefined? (:year date))
date)
(if-not (is-undefined? (:hour time))
time)
(if-not (is-undefined? (:timezone tz))
tz))))
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