Returns the IndexableField(s) from the
shape that are to be added to the
Document. These fields are expected to be marked as indexed and not stored.
Note: If you want to store the shape as a string for retrieval in search results, you could add it like this: document.Add(new StoredField(fieldName, ctx.ToString(shape)));
The particular string representation used doesn't matter to the Strategy since it doesn't use it.
if given a shape incompatible with the strategy