public void initialize() {

        for( Long rootId : roots ) {

            Queue<Long> q = new LinkedList<Long>();
            q.add(rootId);

            while ( !q.isEmpty() ) {

                Long id = q.poll();

                String text = getProcessedTweet(tweetMap.get(id).getTweetText());

                if( text == null || text.length() == 0 )
                    continue;

                if( isEnglish(text) ) {
                    conversationTweetIds.add(id);
                    tweetIdVsTweetText.put(id, text);
                    tweetIdVsSet.put(id, stringToSet(text));
                }

                if( adjacencyList.containsKey(id)) {
                    for (Long childId : adjacencyList.get(id)) {
                        q.add(childId);
                    }
                }
            }

        }

        //System.out.println("Total english tweets in conversation : " + tweetIdVsTweetText.size());

    }