public void map(String key, String value, Context context) {
			String line = value.toString();
			StringTokenizer tokenizer = new StringTokenizer(line);
			while (tokenizer.hasMoreTokens()) {
				String word = tokenizer.nextToken();
				// filter the unnecessary symbols
				Pattern pattern = Pattern.compile("[^\\w]*(\\w?.*\\w)[^\\w]*");
				Matcher matcher = pattern.matcher(word);
				if (matcher.find()) {
					word = matcher.group(1);
					if (word.length() > 0) {
						context.write(word.toLowerCase(), "1");
					}
				}
			}
		}