Closure under Groovy

        // using closure under groovy 
        // to display all contains in directory
        def getFiles = { dir, rtn ->
            dir.listFiles().each { file ->
                if (file.isDirectory()) {
                    getFiles(file, rtn)
                } else {
                    rtn.call(file) // action
                }
            }
        }

        
        getFiles(new File('/Users/tcchou/Desktop/ewtek'), { file ->
            println file.getAbsolutePath()
        })