clojure - 代理和具体化有什么区别？

Question

proxy 和 reify 有什么区别？我有一些示例代码:

(.listFiles (java.io.File. ".")
  (proxy
    [java.io.FileFilter] []
    (accept [f]
      (.isDirectory f))))

(.listFiles (java.io.File. ".")
  (reify
    java.io.FileFilter
    (accept [this f]
      (.isDirectory f))))

结果是一样的，使用proxy和reify哪个更好？

更新:

我发现了一些东西:

• 代理不需要 this 作为第一个参数。
• 代理支持父类(super class)。
• 代理支持参数。

Answer 1

来自Clojure.org's overview of data types :

The method bodies of reify are lexical closures, and can refer to the surrounding local scope. reify differs from proxy in that:

• Only protocols or interfaces are supported, no concrete superclass.
• The method bodies are true methods of the resulting class, not external fns.
• Invocation of methods on the instance is direct, not using map lookup.
• No support for dynamic swapping of methods in the method map.

The result is better performance than proxy, both in construction and invocation. reify is preferable to proxy in all cases where its constraints are not prohibitive.

来源:http://clojure.org/datatypes