diff --git a/LanguageServer/src/main/java/org/nittalab/dtram/languageserver/model/Position.java b/LanguageServer/src/main/java/org/nittalab/dtram/languageserver/model/Position.java
new file mode 100644
index 0000000..0f4fac5
--- /dev/null
+++ b/LanguageServer/src/main/java/org/nittalab/dtram/languageserver/model/Position.java
@@ -0,0 +1,25 @@
+package org.nittalab.dtram.languageserver.model;
+
+/**
+ * {@link Position} class represents positions in text documents.
+ *
+ * @author Shohei Yamagiwa
+ * @since 0.1
+ */
+public class Position {
+    private final int line;
+    private final int column;
+
+    public Position(int line, int column) {
+        this.line = line;
+        this.column = column;
+    }
+
+    public int getLine() {
+        return line;
+    }
+
+    public int getColumn() {
+        return column;
+    }
+}
diff --git a/LanguageServer/src/main/java/org/nittalab/dtram/languageserver/model/Token.java b/LanguageServer/src/main/java/org/nittalab/dtram/languageserver/model/Token.java
new file mode 100644
index 0000000..1d69bad
--- /dev/null
+++ b/LanguageServer/src/main/java/org/nittalab/dtram/languageserver/model/Token.java
@@ -0,0 +1,112 @@
+package org.nittalab.dtram.languageserver.model;
+
+import java.util.Objects;
+
+/**
+ * {@link Token} class represents the part of all texts in model files.
+ *
+ * @author Shohei Yamagiwa
+ * @since 0.1
+ */
+public class Token {
+    /**
+     * A text of the token
+     */
+    private String text;
+
+    /**
+     * A position the token starts
+     */
+    private Position from;
+
+    /**
+     * A position the token ends
+     */
+    private Position to;
+
+    /**
+     * Indicates whether the token is the minimal block or not
+     */
+    private boolean atomic;
+
+    /**
+     * Constructs a new default token.
+     *
+     * @author Shohei Yamagiwa
+     * @since 0.1
+     */
+    public Token() {
+        this.text = "";
+        this.from = new Position(0, 0);
+        this.to = new Position(0, 0);
+        this.atomic = false;
+    }
+
+    /**
+     * Constructs a new token with given properties.
+     *
+     * @param text
+     * @param from
+     * @param to
+     * @param atomic
+     * @author Shohei Yamagiwa
+     * @since 0.1
+     */
+    public Token(final String text, final Position from, final Position to, final boolean atomic) {
+        this.text = text;
+        this.from = from;
+        this.to = to;
+        this.atomic = atomic;
+    }
+
+    public String getText() {
+        return text;
+    }
+
+    public void setText(String text) {
+        this.text = text;
+    }
+
+    public Position getPositionFrom() {
+        return from;
+    }
+
+    public void setPositionFrom(Position from) {
+        this.from = from;
+    }
+
+    public Position getPositionTo() {
+        return to;
+    }
+
+    public void setPositionTo(Position to) {
+        this.to = to;
+    }
+
+    public boolean isAtomic() {
+        return atomic;
+    }
+
+    public void setAtomic(boolean atomic) {
+        this.atomic = atomic;
+    }
+
+    @Override
+    public String toString() {
+        return text + " " + "starts from " + "line: " + from.getLine() + ", " + "column: " + from.getColumn() + " " + "to" + " " + "line: " + to.getLine() + ", " + "column: " + to.getColumn() + ", " + "isAtomic: " + atomic;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        Token other = (Token) o;
+        return Objects.equals(text, other.text) && Objects.equals(from, other.from) && Objects.equals(to, other.to) && Objects.equals(atomic, other.atomic);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(text, from, to, atomic);
+    }
+}
diff --git a/LanguageServer/src/main/java/org/nittalab/dtram/languageserver/model/Tokens.java b/LanguageServer/src/main/java/org/nittalab/dtram/languageserver/model/Tokens.java
new file mode 100644
index 0000000..89d6f02
--- /dev/null
+++ b/LanguageServer/src/main/java/org/nittalab/dtram/languageserver/model/Tokens.java
@@ -0,0 +1,70 @@
+package org.nittalab.dtram.languageserver.model;
+
+/**
+ * {@link Tokens} class holds all tokens used in DTRAM model text.
+ *
+ * @author Shohei Yamagiwa
+ * @since 0.1
+ */
+public class Tokens {
+    public static final String SPACE = " ";
+
+    public static final String CHANNEL = "channel";
+    public static final String INIT = "init";
+    public static final String IN = "in";
+    public static final String OUT = "out";
+    public static final String REF = "ref";
+    public static final String SUB_CHANNEL = "sub";
+    public static final String NATIVE = "native";
+
+    public static final String LEFT_CURLY_BRACKET = "{";
+    public static final String RIGHT_CURLY_BRACKET = "}";
+    public static final String LEFT_CURLY_BRACKET_REGX = "\\{";
+    public static final String RIGHT_CURLY_BRACKET_REGX = "\\}";
+    public static final String LEFT_BRACKET = "(";
+    public static final String RIGHT_BRACKET = ")";
+    public static final String LEFT_BRACKET_REGX = "\\(";
+    public static final String RIGHT_BRACKET_REGX = "\\)";
+    public static final String LEFT_SQUARE_BRACKET = "[";
+    public static final String RIGHT_SQUARE_BRACKET = "]";
+    public static final String LEFT_SQUARE_BRACKET_REGX = "\\[";
+    public static final String RIGHT_SQUARE_BRACKET_REGX = "\\]";
+
+    public static final String ADD = "+";
+    public static final String ADD_REGX = "\\+";
+    public static final String SUB = "-";
+    public static final String SUB_REGX = "\\-";
+    public static final String MUL = "*";
+    public static final String MUL_REGX = "\\*";
+    public static final String DIV = "/";
+    public static final String DIV_REGX = "/";
+    public static final String MOD = "%";
+
+    public static final String MINUS = "-";
+
+    public static final String EQ = "==";
+    public static final String NEQ = "!=";
+    public static final String GT = ">";
+    public static final String LT = "<";
+    public static final String GE = ">=";
+    public static final String LE = "<=";
+    public static final String AND = "&&";
+    public static final String OR = "||";
+    public static final String OR_REGX = "\\|\\|";
+    public static final String NEG = "!";
+
+    public static final String EQUALS = "=";
+    public static final String ASSIGNMENT = "=";
+    public static final String COMMA = ",";
+    public static final String COLON = ":";
+    public static final String DOT = ".";
+    public static final String DOT_REGX = "\\.";
+    public static final String DOUBLE_QUOT = "\"";
+
+    public static final String COMMENT = "//";
+    public static final String COMMENT_REGX = "\\/\\/";
+    public static final String MULTILINE_COMMENT_START = "/*";
+    public static final String MULTILINE_COMMENT_START_REGX = "\\/\\*";
+    public static final String MULTILINE_COMMENT_END = "*/";
+    public static final String MULTILINE_COMMENT_END_REGX = "\\*\\/";
+}
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
new file mode 100644
index 0000000..9efaa8c
--- /dev/null
+++ b/LanguageServer/src/main/java/org/nittalab/dtram/languageserver/utils/Tokenizer.java
@@ -0,0 +1,214 @@
+package org.nittalab.dtram.languageserver.utils;
+
+import org.nittalab.dtram.languageserver.model.Position;
+import org.nittalab.dtram.languageserver.model.Token;
+import org.nittalab.dtram.languageserver.model.Tokens;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.StringReader;
+import java.util.ArrayList;
+
+/**
+ * Tokenizes the model file
+ *
+ * @author Shohei Yamagiwa
+ * @since 0.1
+ */
+public final class Tokenizer {
+    /**
+     * The {@link BufferedReader} that contains model text in memory.
+     */
+    private final BufferedReader reader;
+
+    /**
+     * Initializes {@link Tokenizer} with prepared {@link BufferedReader}
+     *
+     * @param reader Prepared model text in {@link BufferedReader}
+     * @author Shohei Yamagiwa
+     * @since 0.1
+     */
+    public Tokenizer(BufferedReader reader) {
+        this.reader = reader;
+    }
+
+    /**
+     * Initializes {@link Tokenizer} with given {@code text}
+     *
+     * @param text The text from specific model file.
+     * @author Shohei Yamagiwa
+     * @since 0.1
+     */
+    public Tokenizer(String text) {
+        this(new BufferedReader(new StringReader(text)));
+    }
+
+    /**
+     * Tokenizes all texts in {@link BufferedReader}
+     *
+     * @return All tokens in {@link ArrayList}
+     * @throws IOException Be thrown if {@link BufferedReader} fails to read text lines
+     * @author Shohei Yamagiwa
+     * @since 0.1
+     */
+    public ArrayList<Token> execute() throws IOException {
+        ArrayList<Token> allTokens = new ArrayList<>();
+        int line = 1;
+        int column = 1;
+        while (true) {
+            String lineStr = reader.readLine();
+
+            /* No more lines in the buffer. so finish reading */
+            if (lineStr == null) {
+                break;
+            }
+
+            /* Skip empty line */
+            if (lineStr.isEmpty()) {
+                line++;
+                continue;
+            }
+
+            /* Adds whole line as the token */
+            allTokens.add(new Token(lineStr, new Position(line, column), new Position(line, column + lineStr.codePointCount(0, lineStr.length()) - 1), false));
+            line++;
+        }
+        allTokens = splitBySpace(allTokens);
+        allTokens = extractMultilineComments(allTokens);
+        allTokens = extractComments(allTokens);
+        return allTokens;
+    }
+
+    /**
+     * Splits tokens by half-width space.
+     *
+     * @param original Original tokens
+     * @return {@link ArrayList} of {@link Token} extracted by splitting
+     * @author Shohei Yamagiwa
+     * @since 0.1
+     */
+    private ArrayList<Token> splitBySpace(ArrayList<Token> original) {
+        ArrayList<Token> newTokens = new ArrayList<>();
+
+        original.forEach(originalToken -> {
+            String[] tokens = originalToken.getText().split(" ", -1);
+            int line = originalToken.getPositionFrom().getLine();
+            int column = originalToken.getPositionFrom().getColumn();
+            for (int i = 0; i < tokens.length; i++) {
+                String prevToken = i != 0 ? tokens[i - 1] : null;
+                String token = tokens[i];
+                if (token == null) {
+                    break;
+                }
+                int tokenLength;
+
+                /* Count the space between tokens */
+                if (prevToken != null && !prevToken.isBlank() && !token.isBlank()) {
+                    tokenLength = 1;
+                    newTokens.add(new Token(Tokens.SPACE, new Position(line, column), new Position(line, column + tokenLength - 1), true));
+                    column += tokenLength;
+                }
+                if (token.isBlank()) {
+                    tokenLength = 1;
+                    newTokens.add(new Token(Tokens.SPACE, new Position(line, column), new Position(line, column + tokenLength - 1), true));
+                } else {
+                    tokenLength = token.codePointCount(0, token.length());
+                    newTokens.add(new Token(token, new Position(line, column), new Position(line, column + tokenLength - 1), false));
+                }
+                column += tokenLength;
+            }
+        });
+        return newTokens;
+    }
+
+    /**
+     * Extracts multiline comment from given tokens.
+     *
+     * @param original Original tokens
+     * @return {@link ArrayList} of {@link Token} with extracted multiline comments
+     * @author Shohei Yamagiwa
+     * @since 0.1
+     */
+    private ArrayList<Token> extractMultilineComments(ArrayList<Token> original) {
+        ArrayList<Token> newTokens = new ArrayList<>();
+
+        Token commentToken = new Token();
+        boolean isComment = false;
+        StringBuilder commentText = new StringBuilder();
+
+        for (Token originalToken : original) {
+            switch (originalToken.getText()) {
+                case Tokens.MULTILINE_COMMENT_START -> {
+                    commentToken = new Token();
+                    commentToken.setPositionFrom(originalToken.getPositionFrom());
+
+                    commentText.append(originalToken.getText());
+                    isComment = true;
+                }
+                case Tokens.MULTILINE_COMMENT_END -> {
+                    commentText.append(originalToken.getText());
+                    isComment = false;
+
+                    commentToken.setPositionTo(originalToken.getPositionTo());
+                    commentToken.setText(commentText.toString());
+                    commentToken.setAtomic(true);
+
+                    newTokens.add(commentToken);
+                }
+                default -> {
+                    if (isComment) {
+                        commentText.append(originalToken.getText());
+                    } else {
+                        newTokens.add(originalToken);
+                    }
+                }
+            }
+        }
+        return newTokens;
+    }
+
+    /**
+     * Extracts single-line comment from given tokens.
+     *
+     * @param original Original tokens
+     * @return New {@link ArrayList} of {@link Token} with extracted single-line comments
+     * @author Shohei Yamagiwa
+     * @since 0.1
+     */
+    private ArrayList<Token> extractComments(ArrayList<Token> original) {
+        ArrayList<Token> newTokens = new ArrayList<>();
+
+        int commentLine = -1;
+        Token commentToken = new Token();
+
+        for (Token originalToken : original) {
+            if (originalToken.getText().equals(Tokens.COMMENT)) {
+                if (commentLine == -1) {
+                    commentToken = new Token();
+                    commentToken.setText(originalToken.getText());
+                    commentToken.setPositionFrom(originalToken.getPositionFrom());
+                    commentToken.setAtomic(true);
+
+                    commentLine = originalToken.getPositionFrom().getLine();
+                } else if (originalToken.getPositionFrom().getLine() == commentLine && originalToken.getPositionTo().getLine() == commentLine) {
+                    commentToken.setText(commentToken.getText() + originalToken.getText());
+                    commentToken.setPositionTo(originalToken.getPositionTo());
+                }
+            } else {
+                if (commentLine != -1) {
+                    if (originalToken.getPositionFrom().getLine() == commentLine && originalToken.getPositionTo().getLine() == commentLine) {
+                        commentToken.setText(commentToken.getText() + originalToken.getText());
+                        commentToken.setPositionTo(originalToken.getPositionTo());
+                    } else {
+                        newTokens.add(commentToken);
+                        newTokens.add(originalToken);
+                        commentLine = -1;
+                    }
+                } else {
+                    newTokens.add(originalToken);
+                }
+            }
+        }
+        return newTokens;
+    }
+}