Question

在test.groovy中进行以下设置：

class Main {
  public static void main(String ... args) {
    new Child().foo()
  }

  public static class Parent {
    def foo() {
      println 'from parent'
    }
  }

  public static class Child extends Parent {
    def foo() {
      // def superRef = super.&foo  // needed to try what’s commented below
      def myClosure = {
        super.foo()  // doesn’t work, neither does anything of the following:
        // this.super.foo()
        // Child.super.foo()
        // Child.this.super.foo()
        // superRef()
        println 'from child'
      }
      myClosure()
    }
  }
}

当我运行groovy test.groovy（使用Groovy 2.5.4和至少我尝试过的所有其他版本）时，出现以下错误：

Caught: groovy.lang.MissingMethodException: No signature of method: static Main.foo() is applicable for argument types: () values: []
Possible solutions: any(), find(), use([Ljava.lang.Object;), is(java.lang.Object), any(groovy.lang.Closure), find(groovy.lang.Closure)
groovy.lang.MissingMethodException: No signature of method: static Main.foo() is applicable for argument types: () values: []
Possible solutions: any(), find(), use([Ljava.lang.Object;), is(java.lang.Object), any(groovy.lang.Closure), find(groovy.lang.Closure)
    at Main$Child.methodMissing(test.groovy)
    at Main$Child$_foo_closure1.doCall(test.groovy:16)
    at Main$Child$_foo_closure1.doCall(test.groovy)
    at Main$Child.foo(test.groovy:23)
    at Main$Child$foo.call(Unknown Source)
    at Main.main(test.groovy:3)

如何从子类（Parent.foo的相应方法所包围的闭包（myClosure）中引用超类方法（Child.foo）？

（背景：执行我的myCloseable.withCloseable { super.foo(); … }之类的操作需要关闭我的实际代码）

Answer 1

闭包-它是另一个类（就Java而言），您不能从另一个类访问super方法。

IHMO唯一方法：

class Main {
  public static void main(String ... args) {
    new Child().foo()
  }

  public static class Parent {
    def foo() {
      println 'from parent'
    }
  }

  public static class Child extends Parent {
    def superFoo(){
        super.foo()
    }
    def foo() {
      def myClosure = {
        superFoo()
        println 'from child'
      }
      myClosure()
    }
  }
}

Groovy：如何在子类方法中从闭包引用超类方法？

1 个答案: