如何编写通过转换为中间对象进行读写的XStream转换器？

Question

I have a class MyClass . If I serialize it without implementing custom converter it is not human readable.

I implemented MyClassDTO and convertion between MyClass and MyClassDTO .

MyClassDTO is human readable when using XStream standard serialization.

I want to write XStream Converter serialize and deserialize MyClass .
Implementation for Converter.marshal should be following: convert MyClass object to MyClassDTO one and call default serialization for MyClassDTO .

And for Converter.unmarshal : call default deserialization for MyClassDTO object and convert it to MyClass .

How to implement such behaviour in simple way?

I looked through XStream Converter Tutorial , but have not found what I need.

I need to fill the stubs below:

class MatrixConverter<T> : Converter
    where T : new()
{
    public bool CanConvert(Type type)
    {
        return type == typeof(Matrix<T>);
    }

    public void ToXml(object value, Type expectedType, XStreamWriter writer, MarshallingContext context)
    {
        Matrix<T> matrix = value as Matrix<T>;
        if (matrix == null)
        {
            throw new ArgumentException();
        }
        // the code which I am asked about should follow here
    }

    public object FromXml(Type expectedType, XStreamReader reader, UnmarshallingContext context)
    {
        Matrix<T> matrix = null;

        // the code which I am asked about should follow here

    }
}

Answer 1

Try this, assuming

MatrixDTO m = new MatrixDTO( matrix );

converts from your internal matrix type to the DTO.

public void ToXml(object value, Type expectedType, 
    XStreamWriter writer, MarshallingContext context)
{
    context.convertAnother(new MatrixDTO( matrix ));
}

public Object FromXml(Type expectedType, 
    XStreamReader reader, UnmarshallingContext context)
{
    return context.convertAnother(context.currentObject(), MatrixDTO.class);
}

In the unmarshalling case you may have to insert it manually into the context.currentObject(). Haven't tried that myself.

Hope it helps.