Null Object

When To Use (Problems)

• When the problem requires handling of non-declared or non-initialized values.
• When the problem requires a default do nothing parameter.

Example (Solution)

Here is an example in Go:

package main

import (

        "fmt"

)

func Print(d interface{}) {

        if d == nil {

                return

        }

        fmt.Printf("the value is: %v\n", d)

}

func main() {

        Print("Hello")

        Print(5)

        Print(nil)

}

// Output:

// the value is: Hello

// the value is: 5

Notice that when given nil to the Print function, the function does nothing. This allows us to tell the function to "do nothing" instead of allocating some forms of flags.

Expected Outcome (Consequences)

• null object is used as a value or as an indicator of do nothing instead of reserving a value or introducing another flag indicator.