code: public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException
     {
        int length = in.readInt();
        this.remove = new ArrayList<String>(length);
        for (int i = 0; i < length; i++)
        {
           remove.add(in.readUTF());
        }
        this.add = new LinkedList<Document>();
        while (in.readBoolean())
        {
           Document doc = new Document();
           doc.setBoost(in.readFloat());
           int l = in.readInt();
           for (int i = 0; i < l; i++)
           {
              doc.add(readField(in, doc));
           }
           add.add(doc);
        }
     }
docs: {@inheritDoc}