Equivalent for BWAPI C++'s UnitFilter?

[adakitesystems]

Thanks to @SonkoMagnus for mentioning the lack of BWAPI C++'s UnitFilter equivalent in BWAPI4J. Example:

Unit supplyBuilder = 
  u->getClosestUnit(GetType == supplyProviderType.whatBuilds().first 
    && (IsIdle || IsGatheringMinerals) 
    && IsOwned);

where getClosestUnit is declared as:

Unit UnitInterface::getClosestUnit(const UnitFilter &pred, int radius) const

As per @SonkoMagnus's suggestion, we could use Predicate as the equivalent.

[Bytekeeper]

Another option would be Stream style:

Unit supplyBuilder = u.unitsSortedByDistance()
    .filter(u -> u.isIdle() || u.isGatheringMinerals)
    .first()

Where unitsSortedByDistance could also take a maxRadius parameter.