Am 18.01.2012 22:20, schrieb Roger Riggs:
On 01/18/2012 03:09 PM, Joe Darcy wrote:
1. In the new parsing methods, could the String arguments be changed to the
more general
java.lang.CharSequence? For many parsing applications, it could be more
convenient
to pass a CharSequence than to create a new String.
I don't think that would be very helpful in this case. If the methods were changed to take a
CharSequence, the first action I'd write in the method would be to call toString on the argument;
this is necessary to guard against the class of time-of-check-versus-time-of-use problems because
the CharSequence objects can be mutable.
Though the existing methods do operate on immutable inputs, there is no
expectation of synchronization provided by the parsing methods of Integer, etc.
Making the change would not break any existing code because it continues to pass
immutable inputs.
New code that calls the methods using CharSequences, in full knowledge of the
mutability of CharSequences, would manage or avoid the concurrency issues,
most likely by keeping the computation to a single thread or otherwise
synchronizing
changes to the object that implement CharSequence.
Since Integer makes no assurances about being multi-thread safe it can operate
under those assumptions and does not need to make copies of the arguments.
In any case, the copy operation itself could run afoul of concurrency faults,
and it
doesn't matter where the copy occurs, inside or outside of the Integer methods.
Please consider the necessity of extra steps by the developer (to produce
strings)
and the potential savings in the load on the heap by not creating copies of
strings.
Roger
+1
-Ulf
