@Override
	public void addWord(String word) {
		Integer i = sample.get(word);
		
		if (i == null) sample.put(word, 1);
		else 		   sample.put(word, 1 + i.intValue() );
		
		if (sample.size() >= Math.ceil(2. / frequency)) {
			Iterator<String> it = sample.keySet().iterator();
			while (it.hasNext()) {
				String str = it.next();
				int j = sample.get(str);

				if (j == 1)
					it.remove();
				else
					sample.put(str, j - 1);
			}
		}
	}