Converters

Converters in Piriti

Converters

Most of the data read from JSON and XML is converted to the fields type using specific converters. When serializing POJOs to JSON / XML these converters are used to convert from the fields type to string. Therefore Piriti uses the following converters:

• boolean / Boolean → !BooleanConverter
• byte / Byte → !ByteConverter
• char / Character → !CharacterConverter
• double / Double → !DoubleConverter
• float / Float → !FloatConverter
• int / Integer → !IntegerConverter
• long / Long → !LongConverter
• short / Short → !ShortConverter
• java.util.Date → !DateConverter
• java.sql.Date → !SqlDateConverter
• java.sql.Time → !TimeConverter
• java.sql.Timestamp → !TimestampConverter

All converters implement the Converter interface: public interface Converter { /** * Converts the specified value to the type T. * * @param value * The string to be converted. May be null. * @return The converted type or null if a conversion is not * possible */ T convert(String value);

    /**
     * Serializes the specified value to a string.
     * 
     * @param value
     *            The value to serialize. May be <code>null</code>.
     * @return The serialized string or <code>null</code> if no value was given.
     */
    String serialize(T value);
}

Customization

You can customize the built-in converters or write your own: public class BackAndForth { // reader @Format("dd.MM.yy") Date date; @Convert(DurationConverter.class) int duration; }

public class DurationConverter extends AbstractConverter<Integer>
{
    @Override
    public Integer convert(String value)
    {
        if (isValid(value))
        {
            return Integer.valueOf(value.substring(0, value.length() - 1));
        }
        return 0;
    }


    @Override
    public String serialize(Integer value)
    {
        return value + "h";
    }
}

The example uses the @Format annotation so customize the built-in !DateConverter and specifies a custom converter for the duration. Here is the relevant JSON data: { "date": "20.09.04", "duration": "4h" }

Format

For some built-in converters you can specify a custom format using the @Format annotation:

• !DoubleConverter
• !FloatConverter
• !IntegerConverter
• !LongConverter
• !DateConverter

If you want to use a format for your custom converter you have to provide a constructor which takes the format string. The easiest way to do this is to extend from !FormatableConverter<T>: public abstract class FormatableConverter extends AbstractConverter { private final String format;

    public FormatableConverter(String format)
    {
        this.format = format;
    }


    public String getFormat()
    {
        return format;
    }
}