[groovy] closure (closure as function parameter | code example)

One 、 Closures as function arguments

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Make a statement fun function , Sure Declare the parameter as Closure<?> Closure type , In this function , Execute closure content ;

Declare functions :

/** *  Define a method  ,  Receive closures as parameters  ,  Execute the closure content in the method  * @param closure * @return */def fun(Closure<?> closure) { 
        closure()}

When calling the above function , It only needs take Closure treat as Parameters Pass to function that will do :

    fun ({ 
            println "Closure 1"    })

If Closure is the last parameter of the function , Sure Omit parenthesis , Write the closure after the function :

    fun { 
            println "Closure 2"    }

Two 、 Closure as a function parameter code example

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Complete code example :

/** *  Define a method  ,  Receive closures as parameters  ,  Execute the closure content in the method  * @param closure * @return */def fun(Closure<?> closure) { 
        closure()}static void main(String[] args) { 
        fun ({ 
            println "Closure 1"    })    fun { 
            println "Closure 2"    }}

Execution results :

Closure 1Closure 2