| Pattern 8 | Replacing Null Object |
Intent
To avoid scattering null checks throughout our code by encapsulating the action taken for null references into a surrogate null object
Overview
A common way to represent the lack of a value in Java is to use a null reference. This leads to a lot of code that looks like so:
| | if(null == someObject){ |
| | // default null handling behavior |
| | }else{ |
| | someObject.someMethod() |
| | } |
This style leads to scattering null handling logic throughout our code, often repeating it. If we forget to check for null it may lead to a program crashing NullPointerException, even if there is a reasonable default behavior that can handle the lack of a value.
A common solution to this is to create a singleton null object that ...
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