clojure代理始终调用super.method()吗?
-
17-09-2020 - |
题
在使用 clojure代理proxies ,fns
传递给代理应该覆盖现有方法,或者它们与super.method()
一起调用?
在下面的代码中,请求requestHandler.get()与代理生成的get []
调用。
;see: http://github.com/paulosuzart/JTornado
(ns org.ctornadoweb)
(import '(org.jtornadoweb Web$RequestHandler))
(import '(org.jtornadoweb HttpServer Web$Application))
(let [myHandler (proxy [Web$RequestHandler] []
(get []
(.write "Hi CLJ"))
(post []
(.write "POST")))]
(.listen
(HttpServer.
(.add (Web$Application.) "/" (class myHandler))
false nil false) 8089))
.
与编译/继承版本相同:
; Starts a JTornado HTTP Server and a sample RequestHandler.
; Bit verbose due to compilation directives. Recommendation is to generate
; a set of macros to hide this.
(ns org.ctornadoweb
; Compiled and implements a static main method to start the server
(:import (org.jtornadoweb HttpServer)
(org.jtornadoweb.Web$Application)
(org.jtornadoweb.Web$RequestHandler))
(:gen-class :prefix "server-"))
(gen-class
:name org.ctornadoweb.MyHandler
:extends org.jtornadoweb.Web$RequestHandler
:prefix "do")
(defn do-get [this]
"Handles the HTTP GET method"
(.write "hello clojure"))
(defn do-post [this]
"Handles the HTTP POST method"
(.write (.getArgument "name" "default" false)))
(defn server-main []
"main method"
(.listen
(org.jtornadoweb.HttpServer.
(.add (org.jtornadoweb.Web$Application.) "/" org.ctornadoweb.MyHandler)
false nil false) 8089))
;use (compile 'org.ctornadoweb)
.
trace显示了代理正在调用的代理,然后是super.get,什么抛出(默认情况下)例外。
HTTP 405: Method Not Allowed
at org.jtornadoweb.Web$RequestHandler.get(Web.java:72)
at org.ctornadoweb.proxy$org.jtornadoweb.Web$RequestHandler$0.get(Unknown Source)
.
我试图找到有关Clojure代理的实际行为的一些词语。有人可以给这个帮助吗?
解决方案
否,将不会自动调用超级方法,尽管您可以将其明确调用proxy-super
。
以下测试用例显示了他们应该的事项:
user=> (def foo
(proxy [java.util.ArrayList] []
(clear [] (println "not clearing"))))
#'user/foo
user=> (.size foo)
0
user=> (.add foo "hi")
true
user=> (.add foo "bye")
true
user=> (.size foo)
2
user=> (.clear foo)
not clearing
nil
user=> (.size foo)
2
.
如果被称为super.clear()
,则大小将显示为0。
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