Upgrading from 3.6.1 to 4.3.0 and Custom collector

[Peyman Faratin]

Hi 

I am migrating from Lucene 3.6.1 to 4.3.0. I am however not sure how to migrate 
my custom collector below. this page 
http://lucene.apache.org/core/4_3_0/MIGRATE.html gives some hints but the 
instructions are incomplete and looking at the source examples of custom 
collectors make me want to go and eat cheesecake - every time !!!

Any advise would be very much appreciated 

thank you


        public class AllInLinks extends Collector {
                  private Scorer scorer;
                  private int docBase;
                  private String[] store;
                  private HashSet<String> outLinks = new HashSet<String>();

                  public boolean acceptsDocsOutOfOrder() {
                    return true;
                  }
                  public void setScorer(Scorer scorer) {
                    this.scorer = scorer;
                  }
                  public void setNextReader(IndexReader reader, int docBase) 
throws IOException{
                        this.docBase = docBase;
                        store = FieldCache.DEFAULT.getStrings(reader,"title");
                  }
                  public void collect(int doc) throws IOException {
                          String page = store[doc];    
                          outLinks.add(page);
                  }
                  public void reset() {
                          outLinks.clear();
                          store = null;
                  }
                  public int getOutLinks() {
                    return outLinks.size();
                  }
        }