Implemented email validator

Author: somiljain2006

src/main/java/org/spacehub/entities/User.java

@@ -1,4 +1,3 @@
-
 package org.spacehub.entities;
 
 import jakarta.persistence.Entity;
@@ -91,4 +90,4 @@ public boolean isCredentialsNonExpired() {
   public boolean isEnabled() {
     return enabled;
   }
-}
+}

src/main/java/org/spacehub/security/EmailValidator.java

@@ -0,0 +1,22 @@
+package org.spacehub.security;
+
+import org.springframework.stereotype.Service;
+import java.util.function.Predicate;
+import java.util.regex.Pattern;
+
+@Service
+public class EmailValidator implements Predicate<String> {
+
+  private static final String emailRegex =
+    "^(?=.{1,64}@)[A-Za-z0-9_-]+(\\.[A-Za-z0-9_-]+)*@" +
+      "[^-][A-Za-z0-9-]+(\\.[A-Za-z0-9-]+)*(\\.[A-Za-z]{2,})$";
+
+  private static final Pattern pattern = Pattern.compile(emailRegex);
+
+  public boolean test(String email) {
+    if (email == null) {
+      return false;
+    }
+    return pattern.matcher(email).matches();
+  }
+}