是否可以通过Groovy中的类别添加methodMissing钩子？

I wanted to add the methodMissing() to a class which I don't have source code control over. I've tried:

我想将methodMissing()添加到一个我没有源代码控制的类中。我试过了:

class MyClass {} // class I'm not allowed to edit

class MyCategory {

  static def methodMissing(MyClass self, String name, Object args) {
      "I was hoping this was called on a.nonexisting()"
  }

  static def test(MyClass self) {
      "test works"
  }
}

def a = new MyClass()

use(MyCategory) {
    println a.test()
    println a.nonexisting()    
}

But I still get a groovy.lang.MissingMethodException: No signature of method: MyClass.nonexisting() is applicable for argument types: () values: []

但我仍然得到一个groovy.lang.MissingMethodException:没有方法签名:MyClass.nonexisting()适用于参数类型:()值:[]

Is it possible to add a temporary methodMissing to a class?

是否可以在类中添加临时方法?

I was trying to avoid to mess with the meta class since that change will be global and non-reversible.

我试图避免混淆元类,因为这种变化将是全局的,不可逆的。

1 个解决方案

#1

According to Groovy in Action, 2nd Edition published in 2015:

根据Groovy in Action,2015年第2版发布:

Category method names can well take the form of property accessors (pretending property access), operator methods, and GroovyObject methods. MOP hook methods (propertyMissing, methodMissing) cannot be added through a category class. This is a restriction as of Groovy 2.4. The feature may become available in later versions.

类别方法名称可以采用属性访问器(假装属性访问),运算符方法和GroovyObject方法的形式。 MOP钩子方法(propertyMissing,methodMissing)不能通过类别类添加。这是Groovy 2.4的限制。该功能可能会在以后的版本中提供。

So it's not possible to do it in 2.4.12,

所以在2.4.12中不可能这样做,

The release notes for Groovy 2.5 (still in development as 2017-11) don't mention any changes regarding this.

Groovy 2.5的发行说明(仍在开发中,作为2017-11)没有提及任何相关的变化。

The release notes for Groovy 2.6 don't mention it either.

Groovy 2.6的发行说明也没有提到它。

And finally unfortunately the release notes for Groovy 3.0 say nothing about methodMissing

最后不幸的是,Groovy 3.0的发行说明没有提及methodMissing

#1