From: Steven Ketcham <stedak@...>
Date: 2003-06-01T02:00:29+09:00
Subject: newbie questions


Moving from C++

Q1.) Is there an equivalent to enumerated types?
Q2.) Is there an equivalent to the const declaration for function parameters? What prevents a function parameter from being 
accidently changed?
Q3.) Is this the correct way to handle Hash containers and the objects they hold?

Thanks!



class TransCountHolder
   attr_accessor :siteKey, :siteName, :errors, :tranfersCounted, :baudAverage
end

class TransferSummary
    
   # const values - enumerated types???? enum {SiteList, TransferErrorCount, BaudRateAverage, TransferErrorCount}
   SiteList = 0
   TransferErrorCount = 1
   BaudRateAverage = 2
   TransferCount = 3

   def initialize(startDate, endDate, siteKey)
      ...snip...
      @countsContainer = Hash.new
   end
   
   def doSummary
      # site list
      doSql (getSiteListSQL(), SiteList)
   
      # transfer error count
      doSql (getTransferErrorCountSQL(), TransferErrorCount)
      
      # baud rate average
      doSql (getTransferBaudRateAverageSQL(), BaudRateAverage)
      
      # transfer count
      doSql (getTransferCountSQL(), TransferCount)
   end
   
   # what prevents whichFunction parameter from being changed????
   # it would seem the case statement could be replaced by some other language feature????
   def doSql(sqlStmt, whichFunction) 
      database = DatabaseFunctions.new
      database.doSql( sqlStmt ) do |dataset|
         row.each_with_name do |siteKey, value|
            case whichFunction               
               # SiteList
               when SiteList then                                                
                  transferSummaryCountHolder = TransCountHolder.new(siteKey, value)
                  @countsContainer[SiteKey] = transferSummaryCountHolder

               # TransferErrorCount                             
               when TransferErrorCount then @countsContainer[siteKey].errors = value  
               
               # BaudRateAverage
               when BaudRateAverage then @countsContainer[siteKey].baudAverage = value    
               
               # TransferCount
               when TransferCount then @countsContainer[siteKey].tranfersCounted = value   
            end                              
         end                                 
      end
      database.finish
   end
   
   ...various functions snipped...
end