Type conversion

All the examples in the documents are in strings, but fixtures want to process and return other data types.

GreenPepper provides a mechanism to help conversion from String to other data types and back again.

public class SomeFixture {
   public SomeFixture(Ammount ammount) {...}

   public setColor(RGB color) ...
   public someBool(boolean yesNo)..
   public Ratio answer()...
}

Lets look at how GreenPepper will match these.

Converters

Converters are class implementing the interface com.greenpepper.converter.TypeConverter in java or GreenPepper.Converters.ITypeConverter in C#

public interface TypeConverter
{
    boolean canConvertTo( Class type );

    Object parse( String value, Class type );

    String toString( Object value );
}

namespace GreenPepper.Converters
{
    public interface ITypeConverter
    {
        bool CanConvertTo(Type type);

        object ValueOf(string value, Type type);

        string ToString(object value);
    }
}

GreenPepper provides out of the box type converters for the following types

• Integer
• Long
• Float
• Double
• Date
• Boolean
• Array
• String

or their simpler form int, long ...

(order is important see adding a new type converter below)

The ArrayConverter calls recursively the other converters depending on the component type the array holds.

Adding a new type converter

The com.greenpepper.GreenPepper class provides a method to add your own type converter

   public static void registerTypeConverter( TypeConverter converter)

The converters are always check in an LIFO manners. If two converters can process a data type the last one that has been register will be used. That way, you can provides your own converters in place of the standard GreenPepper converters.

Self conversion

Instead of registering a TypeConverter, you can uses self converting types.

Self converting type implies that you add a static parse method to your class.

Java

public static T parse(String val);

And then to revert back to a string,

public static String toString(T value)

C#

public static T ValueOf(string text)

And then to revert back to a string,

public static String ToString(T value)

Your class does not have to provides both of them.

Rules of conversion

From example to fixture

1 First GreenPepper will verify if the type is can self convert (ie public static T parse(String) or public static T ValueOf(string))
2 If not, look for a registered TypeConverter that can handles the type.
3 An UnsupportedOperationException will be thrown

From fixture return value to String

1 First GreenPepper will verify if the type is can self revert (ie public static String toString(T) or public static T ToString(string))
2 If not, look for a registered TypeConverter that can handles the type.
3 Use the toString() or ToString() method on the data itself.