Review Request: 7193406 - Clean-up JDK Build Warnings in java.util, java.io

[Ulf Zibis]

Am 30.08.2012 08:23, schrieb Joe Darcy:
> On 8/29/2012 7:07 PM, Stuart Marks wrote:
>> On 8/29/12 4:56 PM, Joe Darcy wrote:
>>> On 8/29/2012 4:20 PM, Stuart Marks wrote:
>>>> The various SecurityConstants being used here are Strings.
>>>>
>>>> Note that this is doing String comparisons using == which is usually a bug.
>>>> But this code is relying on String interning to provide object identity for
>>>> equal string literals, in order to provide a fast path optimization for these
>>>> common cases. 
Oops, didn't notice that the code is a fastpath in advance.

>>>> Changing this code to use switch-over-strings would be
>>>> semantically equivalent, but it would probably slow things down, since switch
>>>> provides equals() semantics instead of == semantics.
For that reason in project coin I always voted for == semantics as default for switch-on-strings and 
optionally using
     case .equals("foo") :
syntax for equals() semantics.

But anyway, equals() always first checks ==, and in fail switch-on-strings compares the hashes in 
2nd step, so performance should not matter such heavy, compared to the processing which follows, and 
additionally the following code must not slowly process the, I guess also frequent, case of normal 
equality.
Anyway the following code could be faster, if first upper-casing the the actions string instead 
comparing each char against upper AND lower case. A // FIXME tag would be nice for that, to not 
forget the possible tuning in future.

> I recommend explicitly mentioning interning "Using identity comparison against known-interned 
> strings for performance benefit."
I would additionally prefix with: "First using ..." or "Fastpath, using ..."

-Ulf