diff --git a/LanguageServer/src/main/java/org/nittalab/dtram/languageserver/diagnostic/Validator.java b/LanguageServer/src/main/java/org/nittalab/dtram/languageserver/diagnostic/Validator.java
new file mode 100644
index 0000000..8bbb841
--- /dev/null
+++ b/LanguageServer/src/main/java/org/nittalab/dtram/languageserver/diagnostic/Validator.java
@@ -0,0 +1,35 @@
+package org.nittalab.dtram.languageserver.diagnostic;
+
+import org.eclipse.lsp4j.Diagnostic;
+
+import java.util.ArrayList;
+import java.util.List;
+
+// TODO: Implement validator
+
+/**
+ * {@link Validator} class analyzes and validates tokenized model codes and manages all diagnostics.
+ *
+ * @author Shohei Yamagiwa
+ * @since 0.1
+ */
+public final class Validator {
+    /**
+     * Validates with using given text and returns its errors if exists.
+     *
+     * @param text text in the model file or dtram file
+     * @return All diagnostics from given text. or {@code []} if no errors are there.
+     */
+    public List<Diagnostic> validate(String text) {
+        return validate();
+    }
+
+    /**
+     * Validates with using given stream and returns its errors if exists.
+     *
+     * @return All diagnostics from given token stream. or {@code []} if no errors are there.
+     */
+    public List<Diagnostic> validate() {
+        return new ArrayList<>();
+    }
+}