Can Java's ternary/conditional operator (?:) be used to call methods instead of assigning values?

Question

In pages like http://en.wikipedia.org/wiki/?: the ternary/conditional operator ?: seems to be used for conditional assignments. I tried to use it for method cal

Answer 1

The ternary (conditional) operator returns a value. If your methods don't, they can't be used as parts of the operator (where it takes the value).

In order to understand it better, let's think of one simple binary operator: +. It works this way:

 +   -->  

It needs of 2 evaluable parts, and returns another. If you typed

doThis() + doThat();

or even

gimmeAValue = doThis() + doThat();

it would fail, as neither doThis() nor doThat() evaluate to anything (they "return" void). Of course, both and must be of some "compatible" type in order the + operator can handle them and return a value of some type.

Now let's see the ternary operator:

 ?  :   -->  

It takes 3 evaluable parts, and returns a value.

The first evaluable part must be understandable (castable) by the compiler as a boolean. It will be used to decide which of the other 2 evaluable parts has to be returned.

The other two evaluable parts must be, well... evaluable. To something. Of some type.

In other words: the ternary conditional operator is intended to return something, not as code branching. Used this way:

gimmeAValue = testMe() ? returnThis() : returnThat();