Re: [picocontainer-dev] ConfigParameterTestCase / ConfigParameter

Jörg Schaible wrote:

> Paul Hammant wrote:

[snip]

>> .... can't work because valueOf is not part of an interface/
>> abstraction that safe for generics.  You'd have to do that fragment
>> with reflection ... making it uglier and slower.
> 
> Seems I have to learn a lot more about Java generics, I did not expect to
> have here reflection involded at all. C++ templates were a wonderful
> mechanism ;-)

However, does it really make such a significant difference?

Converting 1.000.000 Strings into an Integer:
Direct conversion: 0.461
Reflective conversion: 0.505

Running on JDK 5, old AMD Thunderbird 2.4Mhz

- Jörg


public class Benchmark {
    public static void main(String[] args) throws SecurityException,
NoSuchMethodException, IllegalArgumentException, IllegalAccessException,
InvocationTargetException {
        final int max = 1000000;
        final String[] values = new String[max];
        for (int i = 0; i < values.length; i++ ) {
            values[i] = Integer.toString(i);
        }
        
        long now = System.currentTimeMillis();
        for (int i = 0; i < values.length; i++ ) {
            final Integer iv = Integer.valueOf(values[i]);
            if (iv.intValue() != i) {
                throw new IllegalStateException("Wrong value at " + i);
            }
        }
        System.out.println("Direct conversion: " +
(System.currentTimeMillis() - now) / 1000.0);
        
        Method method = Integer.class.getMethod("valueOf", new Class[
{String.class});   
        now = System.currentTimeMillis();
        for (int i = 0; i < values.length; i++ ) {
            final Integer iv = (Integer)method.invoke(null, values[i]);
            if (iv.intValue() != i) {
                throw new IllegalStateException("Wrong value at " + i);
            }
        }
        System.out.println("Reflective conversion: " +
(System.currentTimeMillis() - now) / 1000.0);
    }
}



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