Something I wanted to pass along - no bug, no fix, just interesting fact...
In the NumberKey code is the following
/**
* Creates a NumberKey equivalent to <code>key</code>.
* Convenience only. Not very efficient at all.
*/
public NumberKey(int key)
{
this.key = new BigDecimal(new Integer(key).toString());
}
The "not very efficient at all" comment caught my eye, so I thought I would
try to speed it up.
I too thought the int->Integer->String->BigDecimal conversion should be a
problem.
I found that it is not at all, in fact the very opposite! I wont waste
everyones time with
all my experiments, but suffice it to say that this is actually the FASTEST
way to create
a BigDecimal from a numeric source. In fact NumberKey(int) is more than
twice as fast as
NumberKey(long)!
My final test ran 1,000,000 iterations of creating
a NumberKey from an integer, then 1,000,000 iterations of creating a
NumberKey from
a long. Here are the results.
1,000,000 NumberKey(int) = 875.0 ms. Time per iteration = 0.000875 ms
1,000,000 NumberKey(long) = 1812.0 ms. Time per iteration = 0.001812 ms
Difference per iteration is 0.000937 ms
for those interested, here is the test code
public static void main(String[] args) {
int intval = 1;
long longval = 1;
double start =0;
// make sure classloader has NumberKey loaded - this made a
difference!
NumberKey z = new NumberKey(1);
start = ((double)System.currentTimeMillis());
for(int i = 0 ; i < 1000000 ; i++){
NumberKey n = new NumberKey(longval);
}
double et = ((double)System.currentTimeMillis())-start;
double itD = et/1000000;
System.out.println("Elapsed Time, long cvt = "+et+" time per
iteration = "+itD);
start = System.currentTimeMillis();
for(int i = 0;i<1000000;i++){
NumberKey n = new NumberKey(intval);
}
et = ((double)System.currentTimeMillis())-start;
double itI = et/1000000;
System.out.println("Elapsed Time, int cvt = "+et+" time per
iteration = "+itI);
System.out.println("Difference is " + (itD - itI));
}
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