This is a super rough prototype of how a new document API could look like. It's basically what I came up with during a long flight across the Atlantic
It is not integrated with anything yet (like IndexWriter, DocumentsWriter, etc.) and heavily uses Java 1.5 features, such as generics and annotations.
The general idea sounds similar to what Marvin is doing in KS, which I found out by reading Mike's comments on LUCENE-831, I haven't looked at the KS API myself yet.
- separate a field's value from its configuration; therefore this patch introduces two classes: FieldDescriptor and FieldValue
- I was thinking that in most cases the documents people add to a Lucene index look alike, i.e. they contain mostly the same fields with the same settings. Yet, for every field instance the DocumentsWriter checks the settings and calls the right consumers, which themselves check settings and return true or false, indicating whether or not they want to do something with that field or not. So I was thinking we could design the document API similar to the Class<->Object concept of OO-languages. There a class is a blueprint (as everyone knows ), and an object is one instance of it. So in this patch I introduced a class called DocumentDescriptor, which contains all FieldDescriptors with the field settings. This descriptor is given to the consumer (IndexWriter) once in the constructor. Then the Document "instances" are created and added via addDocument().
- A Document instance allows adding "variable fields" in addition to the "fixed fields" the DocumentDescriptor contains. For these fields the consumers have to check the field settings for every document instance (like with the old document API). This is for maintaining Lucene's flexibility that everyone loves.
- Disregard the changes to AttributeSource for now. The code that's worth looking at is contained in a new package "newdoc".
Again, this is not a "real" patch, but rather a demo of how a new API could roughly work.