@Override
    protected MapSchema.MessageFactory resolveMapFrom(Input input)
            throws IOException
    {
        final String className = input.readString();
        MapSchema.MessageFactory factory = mapMapping.get(className);
        if (factory == null)
        {
            if (className.indexOf('.') == -1 && MapSchema.MessageFactories.accept(className))
            {
                factory = MapSchema.MessageFactories.valueOf(className);
            }
            else
            {
                factory = new RuntimeMapFactory(RuntimeEnv.loadClass(className));
                MapSchema.MessageFactory f = mapMapping.putIfAbsent(className,
                        factory);
                if (f != null)
                    factory = f;
            }
        }

        return factory;
    }
Used by {@link RuntimeSchema#map(Class, Class)}.
protostuff-runtime/src/main/java/io/protostuff/runtime/DefaultIdStrategy.java