JSeats

JSeats is a java implementation of common electoral seat allocation algorithms.

Questions, bugs and feature requests are welcome on the issues section.

Getting started

The JSeats library offers a seat allocation processor based on the following simple architecture:

You can have example usages here:

• Java API example usage
• BDD stories

Supported methods

• Majority Method
  • Simple (FPTP or First-Past-The-Post)
  • Qualified
  • Absolute
• Ranked Method
  • By votes.
• Equal Proportions Method (aka Huntington-Hill)
• Largest Remainder Method
  • Hare
  • Droop
  • Imperiali
• Highest Averages Method
  • D'Hondt
  • Sainte-Laguë (Webster)
    • Supports user provided first divisor (Modified Sainte-Laguë)
  • Imperiali
  • Danish

Usage

Currently JSeats provides both a clean java API and a command line launcher. A web interface is planned. The command line looks like this:

Usage: JSeats [options]
  Options:
    -c, --candidate
       Add candidate to tally. Candidates follow the format Name:Votes.
    -h, --help
       Print this message.
       Default: false
    -ic, --input-config
       Configuration input file.
    -it, --input-tally
       Tally input file. Overrides tally provided in configuration via
       --input-config, if any.
    -itb, --interactive-tie-breaker
       Resolve ties interactively on the console. Overrides --tie-breaker.
       Default: false
    -ld, --list-decorators
       List built-in result decorators.
       Default: false
    -lf, --list-filters
       List built-in tally filters.
       Default: false
    -lm, --list-methods
       List built-in seat allocation methods.
       Default: false
    -m, --method
       Seat allocation method to use. See --list-methods for available methods.
    -oc, --output-config
       Configuration output file.
    -o, --output-result
       Result output file.
    -ot, --output-tally
       Tally output file.
    -pv, --potential-votes
       Potential votes. If not set, defaults to effective votes (sum of all
       casted votes).
       Default: -1
    -d, --processor-property
       Processor properties as in -D numberOfSeats=105.
    -tb, --tie-breaker
       Resolve ties using provided tie breaker
    -v, --verbose
       Increase level of verbosity.
       Default: false