Hi all! I'd like to add to this discussion that, IMHO, implementation of the EnumSet based on the BitSet class, probably, would be relatively slow. I'd suggest to handle extra case when the number of elements in the enum is <= 64 and it is possible to represent the set with one long value. For this case all the EnumSet API could be implemented using fast bitwise operations.
Thank you. -- Oleg Khaschansky, Intel MPD On 8/3/06, Spark Shen <[EMAIL PROTECTED]> wrote:
Richard Liang 写道: > > > Spark Shen wrote: >> Hi All: >> >> IMHO, EnumSet provides a set view of enum types. According to its >> spec, "Enum sets are represented internally as bit vectors". >> To avoid to re-invent the wheel, it could be more reasonable to >> utilize java.util.BitSet class to support the implementation of EnumSet. >> > Agree :-) > >> While current API methods provided by BitSet is not enough, I need to >> extend the function provided by BitSet. There are 2 options: >> 1. Implement these extension methods in BitSet directly as package >> private methods >> 2. Construct a package private utility class in >> org.apache.harmony.luni.util package, and implement extensions in >> this implementation class. >> >> I prefer the first option, since there is not many classes need these >> extension. If no objections, I will adopt the first schema. >> > IMHO, it depends on the relationship between the extended functions > and the whole class. Would you please provide more detail information? > Thanks a lot. 1. It can be simply detected that on RI, EnumSet.noneOf() or EnumSet.allOf() method will return a concrete EnumSet. This concrete EnumSet provides its own iterator. All these iterator related methods are not implemented in BitSet right now. 2. To support the implementation of EnumSet, more utility methods used to set/unset bits may need to be added. All these requirements are EnumSet specific, do they need to be implemented in a separate class. Best regards > > Richard. >> Best regards. >> > -- Spark Shen China Software Development Lab, IBM --------------------------------------------------------------------- Terms of use : http://incubator.apache.org/harmony/mailing.html To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
