Are there any plans to add a dedicated boolean-reversal operator to Java? The usual syntax is `boolVal = !boolVal;`, but repeating a long variable name can feel inconvenient. Something like `boolVal *= -1;`, `boolVal ^= true;`, or a new form such as `boolVal !=;` or `boolVal!!;` might express the intent more compactly. Is this worth considering, or would the unusual syntax and potential confusion make it too low-priority?
5 Answers
A new operator would save only a few keystrokes while making the code less immediately readable. `boolVal = !boolVal;` is already clear, and a decent IDE can autocomplete even very long variable names. If the name is consistently painful to type, that may be a sign it should be shortened or renamed.
`*= -1` doesn't represent boolean negation. Java booleans aren't numeric values, and even in systems that treat true as 1 and false as 0, multiplying 1 by -1 produces -1, not false. The fact that nonzero values can be treated as truthy in some languages doesn't make that a good Java operation.
You can technically write `boolVal ^= true`, since XOR with true flips a boolean, but I would avoid it. Most Java developers will have to stop and think about what it means, whereas `boolVal = !boolVal;` communicates the operation immediately. A small helper method could be used if this pattern genuinely appears everywhere, though toggling hidden state through methods can also make APIs harder to understand.
If the goal is clearer state management rather than fewer keystrokes, consider passing the desired boolean value into a method or builder instead of exposing a toggle operation. An explicit `enabled(boolean value)` style API is usually easier to read and reason about than behavior that depends on the object's current state.
There isn't a strong language-design case for this feature. Negating a boolean is already concise, and the cases where you need to mutate a flag in place aren't common enough to justify another special operator. Java also deliberately avoids treating booleans as numbers, so an arithmetic-style solution would be especially unintuitive.
I would find `^= true` much more confusing than the normal assignment. Saving three characters isn't worth making maintainers mentally decode a bitwise-looking operation.