Class: ExchangeRatesGenerator::Sources::Base

Inherits:
Object
  • Object
show all
Defined in:
lib/exchange-rates-generator/sources/base.rb

Direct Known Subclasses

Ecb

Class Method Summary collapse

Class Method Details

.inherited(source) ⇒ Object

Records all new Sources



23
24
25
 
# File 'lib/exchange-rates-generator/sources/base.rb', line 23

def inherited(source)
  self.sources << source
end

.rates_for(currency_code) ⇒ Hash

Retrieve a Hash of currency codes and exchange rates, they rates will be relative to currency_code

Parameters:

  • The (String, #to_s) —

    currency code that the exchange rates will be relative to.

Returns:

  • (Hash) —

    The exchange rates, as a Hash of currency codes and exchange rates.



31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
 
# File 'lib/exchange-rates-generator/sources/base.rb', line 31

def rates_for(currency_code)
  # Retrieve the actual rates from the external source
  rates = all_rates

  adjusted_currency = currency_code.to_s.upcase.to_sym          
  unless rates.include?(adjusted_currency)
    raise Errors::CurrencyNotAvailable, "#{adjusted_currency.to_s} was not available in this Source (#{self.to_s}), please use a different Source"
  end

  adjusted_rates = {}

  # Add the currency we are converting to...
  adjusted_rates[adjusted_currency] = 1.0

  # Work out the exchange from our desired currency to our base currency. So if our base was EUR and we wanted USD this would 
  # be how many Euros are in one US dollar.
  adjustment_factor = 1.0 / rates[adjusted_currency]
  adjusted_rates[base_currency] = adjustment_factor

  # Now remove it, since we've already done it.
  rates.delete(base_currency)

  # Now convert the rest
  rates.each do |currency, rate|
    adjusted_rates[currency] = rate * adjustment_factor
  end

  adjusted_rates
end

.sources ⇒ Array

Returns all Sources

Returns:

  • (Array) —

    Array containing all Sources



18
19
20
 
# File 'lib/exchange-rates-generator/sources/base.rb', line 18

def sources
  @sources ||= []
end