refactor:アプリケーション

Refactor password policy validation logic.

Replaces regex-based validation with an iterative approach for better readability and performance. Adds a null check for password input and introduces early exit once all conditions are satisfied.

app/backend/api/src/main/java/com/example/sms/domain/model/system/user/Password.java

@@ -3,9 +3,6 @@
 import lombok.NoArgsConstructor;
 import lombok.Value;
 
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
-
 /**
  * パスワード
  */
@@ -24,14 +21,26 @@ public Password(String value) {
     }
 
     private void checkPolicy(String value) {
-        if (value.length() < 8) {
+        if (value == null || value.length() < 8) {
             throw new PasswordException("パスワードは8文字以上である必要があります");
         }
 
-        String regex = "(?=.*\\d)(?=.*[a-z])(?=.*[A-Z])";
-        Pattern pattern = Pattern.compile(regex);
-        Matcher matcher = pattern.matcher(value);
-        if (!matcher.find()) throw new PasswordException("パスワードは小文字、大文字、数字を含む必要があります");
+        boolean hasDigit = false;
+        boolean hasLower = false;
+        boolean hasUpper = false;
+
+        for (char c : value.toCharArray()) {
+            if (Character.isDigit(c)) hasDigit = true;
+            else if (Character.isLowerCase(c)) hasLower = true;
+            else if (Character.isUpperCase(c)) hasUpper = true;
+
+            // すべての条件を満たしたら早期終了する
+            if (hasDigit && hasLower && hasUpper) break;
+        }
+
+        if (!hasDigit || !hasLower || !hasUpper) {
+            throw new PasswordException("パスワードは小文字、大文字、数字を含む必要があります");
+        }
     }
 
     /**