Lucene is often cited as an excellent example of OO design. I see several areas where this does not seem to be the case, mainly because of the Lucene code uses abstract base classes where it should be using interfaces, and other cases, where an interface makes reference to an abstract base class as a method/return parameter.
It seems the abstract base classes were created so there was a place to put the static 'helper' methods. Would it not be better to have separate interfaces and abstract base classes that the implementations could extend if necessary? Some examples are listed below. Am I missing something, or is the code structured this way for a reason? ----- The main problem seems to be the use of IndexReader in many interfaces, when it should be using a Searchable. Otherwise, what is the point of Searchable. The following object use chain shows the 'pointlessness' of Searchable: Searchable->Query->Weight->IndexReader ----- The Query object has the method: public Query rewrite(IndexReader reader) throws IOException... but the entire search package is based on 'Searchable's, should it not be public Query rewrite(Searchable searchable) throws IOException... If not, the entire idea of 'external' searchable implementations break, because the end up having to 'know' an IndexReader, and IndexReader is a baseclass, etc. The same goes for public Weight weight(Searcher searcher); should this not be a 'Searchable'? ----- The Weight interface has the following: Scorer scorer(IndexReader reader) throws IOException; Should it not be Scorer scorer(Searchable searchable) throws IOException; The same goes for explain(). ----- It seems that Searchable was created because IndexReader was not an interface, but the methods have not been changed to use a Searchable instead of IndexReader. ----- It seems many of the 'search' package classes use a 'Searcher', when they should be using a 'Searchable'. If these core classes really need the methods defined in 'Searcher', then these methods should be moved to 'Searchable'. ----- Shouldn't 'Filter' just be an interface, with the method boolean filter(int docnum); as to whether or not the document should be filtered? ----- --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
