Is the conditional operator more performant than a normal if?

Question

Using the conditional/ternary operator:

freeCache = (freeCache > (2880 * 3)) ? (2880 * 3) : freeCache;

there is a value assignment in every case.

Using this normal if-Statement:

if(this.freeCache > (2880 * 3)) this.freeCache = (2880 * 3)

there should only be a value assignment if the freeCache value is too high.

So which of those is actually more performant?

Answer 1

Just for the fun of it, I tried compiling the two suggested implementations (ternary operator vs the explicit if statement). They both use if_icmple instruction so I guess performance will be identical:

The if version:

public static void main(java.lang.String[]);
Code:
   0: iconst_0
   1: istore_1
   2: iload_1
   3: sipush        8640
   6: if_icmple     13
   9: sipush        8640
  12: istore_1
  13: return

Using '?' ternary operator:

public static void main(java.lang.String[]);
  Code:
   0: iconst_0
   1: istore_1
   2: iload_1
   3: sipush        8640
   6: if_icmple     15
   9: sipush        8640
  12: goto          16
  15: iload_1
  16: istore_1
  17: return

There's a slight inefficiency in using the ? operator (At least in this specific case) due to the : clause (the instructions labeled 15 and 16 in the above listing). The JVM will probably optimize away these redundant operations.

Answer 2

They're not even equivalent .

The ternary expression can be expanded to this:

if(freeCache > (2880 * 3)) {
    freeCache = 2880 * 3;
} else {
    freeCache = freeCache;
}

If you're really concerned about performance, there's a[n insignificant] performance hit in that you're performing a redundant assignment again.

In all cases you should strive for readability first . The single if statement is likely a better choice, as that's more readable than the convoluted ternary expression you have.