问题描述
该笔记将记录：在 Apache Groovy 中，与元编程相关内容，以及常见问题的处理方法。
解决方案
为对象添加新属性及方法
class Foo {}
f = new Foo()
f.metaClass.unVariable = "something"
assert f.hasProperty("unVariable") == true
assert f.unVariable == "something"
f.metaClass.unMethod = { println "Hello World." }
assert f.unMethod() == "Hello World."
invokeMethod
在方法调用前，如果实现 invokeMethod() 方法，将调用该方法：
class MyClass implements GroovyInterceptable {
def invokeMethod(String name, args) {
System.out.println("This method is called method $name")
def metaMethod = metaClass.getMetaMethod(name, args)
metaMethod.invoke(this, args)
}
def myMethod() {
"Hi!"
}
}
def instance = new MyClass()
instance.myMethod()
或者，通过 metaClass 实现：
Integer.metaClass.invokeMethod = { String name, args ->
println("This method is called method $name")
def metaMethod = delegate.metaClass.getMetaMethod(name, args)
metaMethod.invoke(delegate, args)
}
1.toString()
参考文献
How to verify if an object has certain property?
Dynamically add a property or method to an object in groovy
The Apache Groovy programming language – Runtime and compile-time metaprogramming
reflection – Find out a method’s name in Groovy – Stack Overflow