Name: bk70084 Date: 06/24/98


Hi!

I am proposing a new null-safe operator for field
access in Java. I'm using "?." for the notation
in the example below:

  class Base
  {
    Integer member;
  }
    ...

  static Integer getMember( Base b )
  {
    Integer result;

    // Simplest way to code this function will
    // throw a NullPointerException when 'b' is
    // a null object:

    result = b.member;

    // .. or, to avoid, the exception, some code
    // must be added to explicitly check the base
    // object:

    result = b == null ? null : b.member;

    // My suggestion: add operator "?." which
    // returns null if its left-hand-side base
    // object is null and otherwise returns the
    // field referred to by the right-hand-side:

    result = b?.member;

    // E.g. the third assignment works like the
    // second while it looks much like the first
    // assignment.

    // In particular, the third assignment shall
    // never throw a NullPointerException.

    return result;
  }


Although my proposal is just for convenience and
has rather obvious workaround, I would be glad if
you took it into some consideration.

terv: Risto Lankinen
(Review ID: 34107)
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