1.1 --- a/currency/test/org/apidesign/apifest08/test/Task1Test.java	Sun Sep 28 18:41:43 2008 +0200
     1.2 +++ b/currency/test/org/apidesign/apifest08/test/Task1Test.java	Sun Sep 28 20:05:56 2008 +0200
     1.3 @@ -22,8 +22,19 @@
     1.4      protected void tearDown() throws Exception {
     1.5      }
     1.6  
     1.7 +    //
     1.8 +    // Imagine that there are three parts of the whole system:
     1.9 +    // 1. there is someone who knows the current exchange rate
    1.10 +    // 2. there is someone who wants to do the conversion
    1.11 +    // 3. there is the API between 1. and 2. which allows them to communicate
    1.12 +    // Please design such API
    1.13 +    //
    1.14 +
    1.15      /** Create convertor that understands two currencies, CZK and
    1.16 -     *  USD. Make 1 USD == 17 CZK.
    1.17 +     *  USD. Make 1 USD == 17 CZK. This is a method provided for #1 group -
    1.18 +     *  e.g. those that know the exchange rate. They somehow need to create
    1.19 +     *  the objects from the API and tell them the exchange rate. The API itself
    1.20 +     *  knows nothing about any rates, before the createCZKtoUSD method is called.
    1.21       *
    1.22       * Creation of the convertor shall not require subclassing of any class
    1.23       * or interface on the client side.
    1.24 @@ -35,7 +46,11 @@
    1.25      }
    1.26  
    1.27      /** Create convertor that understands two currencies, CZK and
    1.28 -     *  SKK. Make 100 SKK == 80 CZK.
    1.29 +     *  SKK. Make 100 SKK == 80 CZK. Again this is method for the #1 group -
    1.30 +     *  it knows the exchange rate, and needs to use the API to create objects
    1.31 +     *  with the exchange rate. Anyone shall be ready to call this method without
    1.32 +     *  any other method being called previously. The API itself shall know
    1.33 +     *  nothing about any rates, before this method is called.
    1.34       *
    1.35       * Creation of the convertor shall not require subclassing of any class
    1.36       * or interface on the client side.
    1.37 @@ -45,6 +60,13 @@
    1.38      public static Convertor createSKKtoCZK() {
    1.39          return null;
    1.40      }
    1.41 +
    1.42 +    //
    1.43 +    // now the methods for group #2 follow:
    1.44 +    // this group knows nothing about exchange rates, but knows how to use
    1.45 +    // the API to do conversions. It somehow (by calling one of the factory
    1.46 +    // methods) gets objects from the API and uses them to do the conversions.
    1.47 +    //
    1.48      
    1.49      /** Use the convertor from <code>createCZKtoUSD</code> method and do few conversions
    1.50       * with it.
    1.51 @@ -72,5 +94,20 @@
    1.52          // convert 500SKK to CZK
    1.53          // assertEquals("Result is 400 CZK");
    1.54      }
    1.55 +
    1.56 +    /** Verify that the CZK to USD convertor knows nothing about SKK.
    1.57 +     */
    1.58 +    public void testCannotConvertToSKKwithCZKUSDConvertor() throws Exception {
    1.59 +        Convertor c = createCZKtoUSD();
    1.60 +        // convert $5 to SKK, the API shall say this is not possible
    1.61 +        // convert 500 SKK to CZK, the API shall say this is not possible
    1.62 +    }
    1.63 +
    1.64 +    /** Verify that the CZK to SKK convertor knows nothing about USD.
    1.65 +     */
    1.66 +    public void testCannotConvertToSKKwithCZKUSDConvertor() throws Exception {
    1.67 +        Convertor c = createSKKtoCZK();
    1.68 +        // convert $5 to SKK, the API shall say this is not possible
    1.69 +        // convert 500 CZK to USD, the API shall say this is not possible
    1.70 +    }
    1.71  }
    1.72 -