diff --git a/LanguageServer/src/main/java/org/nittalab/dtram/languageserver/utils/Tokenizer.java b/LanguageServer/src/main/java/org/nittalab/dtram/languageserver/utils/Tokenizer.java
index 2a241d2..106c45a 100644
--- a/LanguageServer/src/main/java/org/nittalab/dtram/languageserver/utils/Tokenizer.java
+++ b/LanguageServer/src/main/java/org/nittalab/dtram/languageserver/utils/Tokenizer.java
@@ -53,7 +53,57 @@
      * @since 0.1
      */
     public final List<Token> execute() throws IOException {
-        List<Token> allTokens = new ArrayList<>();
+        List<Token> tokens = splitByLine(reader);
+        tokens = splitBySpace(tokens);
+        tokens = extractMultilineComments(tokens);
+        tokens = extractComments(tokens);
+
+        tokens = splitTokens(tokens, Tokens.EQ);
+        tokens = splitTokens(tokens, Tokens.NEQ);
+        tokens = splitTokens(tokens, Tokens.GE);
+        tokens = splitTokens(tokens, Tokens.LE);
+        tokens = splitTokens(tokens, Tokens.AND);
+        tokens = splitTokens(tokens, Tokens.OR);
+
+        tokens = splitTokens(tokens, Tokens.LEFT_BRACKET);
+        tokens = splitTokens(tokens, Tokens.RIGHT_BRACKET);
+        tokens = splitTokens(tokens, Tokens.LEFT_CURLY_BRACKET);
+        tokens = splitTokens(tokens, Tokens.RIGHT_CURLY_BRACKET);
+        tokens = splitTokens(tokens, Tokens.LEFT_SQUARE_BRACKET);
+        tokens = splitTokens(tokens, Tokens.RIGHT_SQUARE_BRACKET);
+
+        tokens = splitTokens(tokens, Tokens.ADD);
+        tokens = splitTokens(tokens, Tokens.SUB);
+        tokens = splitTokens(tokens, Tokens.MUL);
+        tokens = splitTokens(tokens, Tokens.DIV);
+        tokens = splitTokens(tokens, Tokens.MOD);
+
+        tokens = splitTokens(tokens, Tokens.MINUS);
+
+        tokens = splitTokens(tokens, Tokens.GT);
+        tokens = splitTokens(tokens, Tokens.LT);
+        tokens = splitTokens(tokens, Tokens.NEG);
+
+        tokens = splitTokens(tokens, Tokens.EQUALS);
+        tokens = splitTokens(tokens, Tokens.ASSIGNMENT);
+        tokens = splitTokens(tokens, Tokens.COLON);
+        tokens = splitTokens(tokens, Tokens.COMMA);
+        tokens = splitTokens(tokens, Tokens.DOT);
+        tokens = splitTokens(tokens, Tokens.DOUBLE_QUOT);
+        return tokens;
+    }
+
+    /**
+     * Reads lines from {@code reader} and convert each of them into a token.
+     *
+     * @param reader {@link BufferedReader} to read lines.
+     * @return {@link List} of converted tokens.
+     * @throws IOException Thrown when reading from buffer failed.
+     * @author Shohei Yamagiwa
+     * @since 0.1
+     */
+    protected static List<Token> splitByLine(BufferedReader reader) throws IOException {
+        List<Token> tokens = new ArrayList<>();
         int line = 1;
         int column = 1;
         while (true) {
@@ -71,48 +121,12 @@
             }
 
             /* Adds whole line as the token */
-            allTokens.add(new Token(lineStr, new Position(line, column), false));
+            tokens.add(new Token(lineStr, new Position(line, column), false));
             line++;
         }
         reader.close();
 
-        allTokens = splitBySpace(allTokens);
-        allTokens = extractMultilineComments(allTokens);
-        allTokens = extractComments(allTokens);
-
-        allTokens = splitTokens(allTokens, Tokens.EQ);
-        allTokens = splitTokens(allTokens, Tokens.NEQ);
-        allTokens = splitTokens(allTokens, Tokens.GE);
-        allTokens = splitTokens(allTokens, Tokens.LE);
-        allTokens = splitTokens(allTokens, Tokens.AND);
-        allTokens = splitTokens(allTokens, Tokens.OR);
-
-        allTokens = splitTokens(allTokens, Tokens.LEFT_BRACKET);
-        allTokens = splitTokens(allTokens, Tokens.RIGHT_BRACKET);
-        allTokens = splitTokens(allTokens, Tokens.LEFT_CURLY_BRACKET);
-        allTokens = splitTokens(allTokens, Tokens.RIGHT_CURLY_BRACKET);
-        allTokens = splitTokens(allTokens, Tokens.LEFT_SQUARE_BRACKET);
-        allTokens = splitTokens(allTokens, Tokens.RIGHT_SQUARE_BRACKET);
-
-        allTokens = splitTokens(allTokens, Tokens.ADD);
-        allTokens = splitTokens(allTokens, Tokens.SUB);
-        allTokens = splitTokens(allTokens, Tokens.MUL);
-        allTokens = splitTokens(allTokens, Tokens.DIV);
-        allTokens = splitTokens(allTokens, Tokens.MOD);
-
-        allTokens = splitTokens(allTokens, Tokens.MINUS);
-
-        allTokens = splitTokens(allTokens, Tokens.GT);
-        allTokens = splitTokens(allTokens, Tokens.LT);
-        allTokens = splitTokens(allTokens, Tokens.NEG);
-
-        allTokens = splitTokens(allTokens, Tokens.EQUALS);
-        allTokens = splitTokens(allTokens, Tokens.ASSIGNMENT);
-        allTokens = splitTokens(allTokens, Tokens.COLON);
-        allTokens = splitTokens(allTokens, Tokens.COMMA);
-        allTokens = splitTokens(allTokens, Tokens.DOT);
-        allTokens = splitTokens(allTokens, Tokens.DOUBLE_QUOT);
-        return allTokens;
+        return tokens;
     }
 
     /**