From 6b7dcdf847e0b7875f97c5b80760d2d6ba36c70c Mon Sep 17 00:00:00 2001
From: Ashish Gupta <30566001+gupta-ashu01@users.noreply.github.com>
Date: Sat, 7 Aug 2021 12:34:38 +0530
Subject: [PATCH] Add files via upload

---
 .../emailvalidation/EmailValidation.java      | 64 +++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 core-java-modules/core-java-string-algorithms-3/src/main/java/com/baeldung/emailvalidation/EmailValidation.java

diff --git a/core-java-modules/core-java-string-algorithms-3/src/main/java/com/baeldung/emailvalidation/EmailValidation.java b/core-java-modules/core-java-string-algorithms-3/src/main/java/com/baeldung/emailvalidation/EmailValidation.java
new file mode 100644
index 0000000000..97d1b90ff3
--- /dev/null
+++ b/core-java-modules/core-java-string-algorithms-3/src/main/java/com/baeldung/emailvalidation/EmailValidation.java
@@ -0,0 +1,64 @@
+package com.baeldung.emailvalidation;
+
+import java.util.regex.Pattern;
+
+public class EmailValidation {
+
+    private static String regexPattern;
+
+    public static boolean usingSimpleRegex(String emailAddress) {
+        regexPattern = "^(.+)@(\\S+)$";
+
+        return Pattern.compile(regexPattern)
+            .matcher(emailAddress)
+            .matches();
+    }
+
+    public static boolean usingStrictRegex(String emailAddress) {
+        regexPattern = "^(?=.{1,64}@)[A-Za-z0-9_-]+(\\.[A-Za-z0-9_-]+)*@" + "[^-][A-Za-z0-9-]+(\\.[A-Za-z0-9-]+)*(\\.[A-Za-z]{2,})$";
+
+        return Pattern.compile(regexPattern)
+            .matcher(emailAddress)
+            .matches();
+    }
+
+    public static boolean usingUnicodeRegex(String emailAddress) {
+        regexPattern = "^(?=.{1,64}@)[\\p{L}0-9_-]+(\\.[\\p{L}0-9_-]+)*@" + "[^-][\\p{L}0-9-]+(\\.[\\p{L}0-9-]+)*(\\.[\\p{L}]{2,})$";
+
+        return Pattern.compile(regexPattern)
+            .matcher(emailAddress)
+            .matches();
+    }
+
+    public static boolean usingRFC5322Regex(String emailAddress) {
+        regexPattern = "^[a-zA-Z0-9_!#$%&'*+/=?`{|}~^.-]+@[a-zA-Z0-9.-]+$";
+
+        return Pattern.compile(regexPattern)
+            .matcher(emailAddress)
+            .matches();
+    }
+
+    public static boolean restrictDots(String emailAddress) {
+        regexPattern = "^[a-zA-Z0-9_!#$%&'*+/=?`{|}~^-]+(?:\\.[a-zA-Z0-9_!#$%&'*+/=?`{|}~^-]+)*@" + "[a-zA-Z0-9-]+(?:\\.[a-zA-Z0-9-]+)*$";
+
+        return Pattern.compile(regexPattern)
+            .matcher(emailAddress)
+            .matches();
+    }
+
+    public static boolean owaspValidation(String emailAddress) {
+        regexPattern = "^[a-zA-Z0-9_+&*-]+(?:\\.[a-zA-Z0-9_+&*-]+)*@(?:[a-zA-Z0-9-]+\\.)+[a-zA-Z]{2,7}$";
+
+        return Pattern.compile(regexPattern)
+            .matcher(emailAddress)
+            .matches();
+    }
+
+    public static boolean topLevelDomain(String emailAddress) {
+        regexPattern = "^[\\w!#$%&'*+/=?`{|}~^-]+(?:\\.[\\w!#$%&'*+/=?`{|}~^-]+)*" + "@(?:[a-zA-Z0-9-]+\\.)+[a-zA-Z]{2,6}$";
+
+        return Pattern.compile(regexPattern)
+            .matcher(emailAddress)
+            .matches();
+    }
+}
\ No newline at end of file