Lombok-free paginated view iterator for jcouchdb (cf https://gist.github.com/1986550)

gistfile1.java

import java.util.Iterator;
import java.util.List;

import org.jcouchdb.db.Database;
import org.jcouchdb.db.Options;
import org.jcouchdb.document.Document;
import org.jcouchdb.document.ValueRow;
import org.jcouchdb.document.ViewResult;

// Fast view pagination method described at http://guide.couchdb.org/draft/recipes.html#fast
public class PaginatedViewIterator<T extends Document> implements Iterator<List<ValueRow<T>>> 
{
    private Database database;
    private String view;
    
    private Class<T> documentClass;
    private int rowsPerPage;
    
    private Object nextStartKey;
    private String nextStartKeyDocId;
    
    private boolean hasNext = true;
    
    public PaginatedViewIterator (Database database, String view, Class<T> documentClass, int rowsPerPage)
    {
        this.database = database;
        this.view = view;
        
        this.documentClass = documentClass;
        this.rowsPerPage = rowsPerPage;
    }
    
    public boolean hasNext ()
    {
        return hasNext;
    }
    
    public List<ValueRow<T>> next()
    {
        Options options = new Options().limit (rowsPerPage + 1);
        if (nextStartKey != null && nextStartKeyDocId != null)
            options.startKey (nextStartKey)
                   .startKeyDocId (nextStartKeyDocId);
        
        ViewResult<T> result = database.queryView (view, documentClass, options, null);
        
        List<ValueRow<T>> allRows = result.getRows ();
        int count = allRows.size ();

        if (count <= rowsPerPage)
        {
            hasNext = false;
            return allRows;
        }
        
        List<ValueRow<T>> rows = allRows.subList (0, rowsPerPage);
        ValueRow<T> lastRow = allRows.get (count - 1);
        
        nextStartKey = lastRow.getKey ();
        nextStartKeyDocId = lastRow.getId ();
        
        return rows;
    }
 
    @Override
    public void remove ()
    {
        throw new IllegalStateException ("not supported");
    }
}