moneydesktop/rubiks

# Taken from mondrian-olap: https://github.com/rsim/mondrian-olap/blob/master/lib/mondrian/olap/error.rb
module ::Rubiks

  class MondrianError < StandardError
    NATIVE_MONDRIAN_ERROR_REGEXP = /^(org\.olap4j\.|mondrian\.|java\.lang\.reflect\.UndeclaredThrowableException\: Mondrian Error\:)/

    # root_cause will be nil if there is no cause for wrapped native error
    # root_cause_message will have either root_cause message or wrapped native error message
    attr_reader :native_error, :root_cause_message, :root_cause

    def initialize(native_error)
      @native_error = native_error
      get_root_cause
      super(@root_cause_message)
      add_root_cause_to_backtrace
    end

    def self.wrap_native_exception
      yield
    rescue NativeException => e
      if e.message =~ NATIVE_MONDRIAN_ERROR_REGEXP
        raise ::Rubiks::MondrianError.new(e)
      else
        raise
      end
    end

    private

    def get_root_cause
      @root_cause = nil
      e = @native_error
      while e.respond_to?(:cause) && (cause = e.cause)
        @root_cause = e = cause
      end
      message = e.message
      if message =~ /\AMondrian Error:(.*)\Z/m
        message = $1
      end
      @root_cause_message = message
    end

    def add_root_cause_to_backtrace
      bt = @native_error.backtrace
      if @root_cause
        root_cause_bt = Array(@root_cause.backtrace)
        root_cause_bt[0,5].reverse.each do |bt_line|
          bt.unshift "root cause:   #{bt_line}"
        end
        bt.unshift "root cause: #{@root_cause.java_class.name}: #{@root_cause.message.chomp}"
      end
      set_backtrace bt
    end
  end

end