[英]Groovy: add a method to a closure
I have the following closure 我有以下关闭
def closure = {
println ("closure code")
}
And i would like to add a method to it. 我想为其添加一种方法。 but if I try
但是如果我尝试
closure.metaClass.fun = { c->
c.call();
println ("extra code");
}
I get an Exception 我得到一个例外
groovy.lang.MissingPropertyException: No such property: fun for class: org.codehaus.groovy.runtime.metaclass.ClosureMetaClass
Reading another answer, i also blindly tried to call 阅读另一个答案,我也盲目地打电话给
ExpandoMetaClass.enableGlobally()
but it's not working. 但它不起作用。
Is there a way to achive what I want? 有没有办法实现我想要的?
You can do: 你可以做:
def closure = {
println "closure code"
}
closure.getMetaClass().fun = { ->
delegate.call()
println "extra code"
}
closure.fun()
Which prints: 哪些打印:
closure code
extra code
Another simpler approach could be: 另一种更简单的方法可能是:
def closure = {
println "closure code"
}
closure.fun = { ->
closure()
println "extra code"
}
closure.fun()
The downside of this approach is that I'm referencing the closure variable directly though, instead of going through the delegate. 这种方法的缺点是我直接引用了闭包变量,而不是通过委托。
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