The null object pattern
is a design pattern that simplifies the use of dependencies that can be
undefined. This is achieved by using instances of a concrete class that
implements a known interface, instead of null references.
"Unfortunately, using
null tends to complicate the code."
From the blog:
"When you develop classes that have dependencies, you will
sometimes have cases where a dependency is not needed, perhaps because the
normal behaviour of the dependency is not required. One way to deal with such a
situation is to use a null reference instead of a real object for that
dependency. Unfortunately, using null tends to complicate the code. Wherever
you need to use a member from the object, you must first check if it is null,
as calling a method or accessing a property of a null reference will cause an
exception."
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