On 10/31/2015 07:29 PM, Remi Forax wrote:
also instead of Optional.orElse, orElseGet is better because it avoids to
evaluate
Thread.currentThread().getClass() if not necessary.
So the example should be:
walk(s -> s.map(StackFrame::getDeclaringClass)
.findFirst()).orElseGet(() -> Thread.currentThread().getClass());
It might be hard to believe, but the evaluation of constant lambda
expression is approx. equally expensive as the expression it
encapsulates in this example, so it really is an overkill here:
Benchmark Mode Cnt
Score Error Units
LambdaVsCurrentThreadBench.getCurrentThreadClass avgt 10
2.202 ± 0.058 ns/op
LambdaVsCurrentThreadBench.getCurrentThreadClassSupplier avgt 10
2.196 ± 0.159 ns/op
@BenchmarkMode(Mode.AverageTime)
@Fork(1)
@Warmup(iterations = 5)
@Measurement(iterations = 10)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
public class LambdaVsCurrentThreadBench {
@Benchmark
public Class<?> getCurrentThreadClass() {
return Thread.currentThread().getClass();
}
@Benchmark
public Supplier<Class<?>> getCurrentThreadClassSupplier() {
return () -> Thread.currentThread().getClass();
}
}
Regards, Peter
