Clojure使用重载方法对Java接口进行验证 [英] Clojure reify a Java interface with overloaded methods

问题描述

我正在尝试在Clojure中实现以下Java接口：

I'm trying to implement the following Java interface in Clojure:

package quickfix;

public interface MessageFactory {
    Message create(String beginString, String msgType);
    Group create(String beginString, String msgType, int correspondingFieldID);
}

以下Clojure代码是我尝试执行的操作：

The following Clojure code is my attempt at doing this:

(defn -create-message-factory 
  []
  (reify quickfix.MessageFactory
    (create [beginString msgType]
      nil)
    (create [beginString msgType correspondingFieldID]
      nil)))

此操作无法编译并显示错误：

This fails to compile with the error:

java.lang.IllegalArgumentException：无法在接口中定义方法：创建

java.lang.IllegalArgumentException: Can't define method not in interfaces: create

文档建议重载接口方法是可以的，只要在这种情况下Arity不同即可。

The documentation suggests overloaded interface methods are ok, so long as the arity is different as it is in this case:

如果方法在协议/接口中重载，则必须提供多个
独立的方法定义。如果在接口中由于
相同的重载而过载，则必须指定完整的提示以消除
的歧义-缺少提示暗示对象。

If a method is overloaded in a protocol/interface, multiple independent method definitions must be supplied. If overloaded with same arity in an interface you must specify complete hints to disambiguate - a missing hint implies Object.

如何使它正常工作？

推荐答案

您缺少参数。 reify 实现的每个方法的第一个参数是对象本身（与 defrecord / <$ c一样） $ c> deftype ）。因此，尝试以下操作：

You're missing a parameter. The first parameter of every method implemented by reify is the object itself (as is the case with defrecord/deftype). So, try this:

(defn -create-message-factory 
  []
  (reify quickfix.MessageFactory
    (create [this beginString msgType]
      nil)
    (create [this beginString msgType correspondingFieldID]
      nil)))

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