JDK-4938537 : (coll) Extension of Collection Framework
  • Type: Enhancement
  • Component: core-libs
  • Sub-Component: java.util:collections
  • Affected Version: 1.4.2
  • Priority: P4
  • Status: Closed
  • Resolution: Cannot Reproduce
  • OS: windows_xp
  • CPU: x86
  • Submitted: 2003-10-16
  • Updated: 2012-10-08
  • Resolved: 2011-04-05
Name: rmT116609			Date: 10/15/2003

The package adds to the Collection Framework several classes for representing
multisets (bags) or "sets of sets" backed by a hash table. Also, there is now
a class for representing "mathematical sets" implementing the usual
mathematical functions in a non-destructive fashion (as you would expect a
"function" to behave).

The new methods offer a much improved runtime performance due to the use
of effective hash code routines.

The design and implementation of the new classes and methods is very
consistent with the existing CFW structures.

Most importantly, the Collection Framework was lacking efficient classes
for handling multisets, "sets of sets" and handling normal sets in a
way that would be suitable for mathematical applications.
Furthermore, the existing hash code methods for sets or collections were not
as efficient as they could be. Simply summing up the hash codes of the set
elements could lead to suboptimal runtime behavior. The new classes and
methods offer significantly increased performance resulting from the use
of more effective hash code routines.
A consistent extension of the CFW that implements the improvements mentioned
above can be found at
(Incident Review ID: 215942) 

EVALUATION Offered samples at "http://www.informatik.uni-stuttgart.de/ifi/is/Personen/lippold/MathCollection/" are no longer available.