[groovy] mop meta object protocol and meta programming (execute groovy methods through metamethod invoke)

One 、 adopt MetaMethod#invoke perform Groovy Method

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Already defined Groovy class Student , And create this kind of object ;

class Student { 
        def name;    def hello() { 
            println "Hello ${name}"    }}def student = new Student(name: "Tom")

adopt MetaMethod#invoke perform Groovy Method :

First , obtain Groovy Object's MetaClass ,

student.getMetaClass()

then , call MetaClass#getMetaMethod Method obtain MetaMethod object ,

MetaMethod metaMethod = student.getMetaClass().getMetaMethod("name", null)

Last , call MetaMethod#invoke Method , Execute the acquired MetaMethod Corresponding Groovy Method ;

metaMethod.invoke(student, null)

Two 、 Complete code example

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Complete code example :

class Student { 
        def name;    def hello() { 
            println "Hello ${name}"    }}def student = new Student(name: "Tom")//  Call directly  hello  Method student.hello()//  adopt  GroovyObject#invokeMethod  call  hello  Method //  The second parameter is the function parameter  ,  If  void  Then in  nullstudent.invokeMethod("hello", null)//  obtain   Metamethod MetaMethod metaMethod = student.getMetaClass().getMetaMethod("name", null)//  Execution meta method metaMethod.invoke(student, null)

Execution results :

Hello TomHello TomHello Tom