refactor: Optimised codes.

Move all private or protected to the last of files.

devkit-utils/src/main/java/cn/org/codecrafters/devkit/utils/AesUtil.java

@@ -44,13 +44,6 @@ import java.util.UUID;
 @Slf4j
 public final class AesUtil {
 
-    private AesUtil() {
-    }
-
-    private static final String AES = "AES";
-
-    private static final String AES_CBC_CIPHER = "AES/CBC/PKCS5Padding";
-
     /**
      * Encrypts the data using the AES algorithm with the given secret.
      *
@@ -133,4 +126,20 @@ public final class AesUtil {
         return UUID.randomUUID().toString().replaceAll("-", "").substring(0, 16);
     }
 
+    /**
+     * Private constructor will protect this class from being instantiated.
+     */
+    private AesUtil() {
+    }
+
+    /**
+     * The algorithm AES.
+     */
+    private static final String AES = "AES";
+
+    /**
+     * The algorithm AES/CBC/PKCS5Padding.
+     */
+    private static final String AES_CBC_CIPHER = "AES/CBC/PKCS5Padding";
+
 }

devkit-utils/src/main/java/cn/org/codecrafters/devkit/utils/Base64Util.java

@@ -56,14 +56,6 @@ import java.util.Objects;
  */
 public final class Base64Util {
 
-    private static Base64.Encoder encoder;
-
-    private static Base64.Decoder decoder;
-
-    private static Base64.Encoder urlEncoder;
-
-    private static Base64.Decoder urlDecoder;
-
     /**
      * Ensure that there is only one Base64 Encoder.
      *
@@ -210,4 +202,12 @@ public final class Base64Util {
         return decodeUrlComponents(value, StandardCharsets.UTF_8);
     }
 
+    private static Base64.Encoder encoder;
+
+    private static Base64.Decoder decoder;
+
+    private static Base64.Encoder urlEncoder;
+
+    private static Base64.Decoder urlDecoder;
+
 }

devkit-utils/src/main/java/cn/org/codecrafters/devkit/utils/BranchUtil.java

@@ -77,11 +77,6 @@ import java.util.function.Supplier;
  */
 public final class BranchUtil<T> {
 
-    /**
-     * The final result of the boolean expression.
-     */
-    private final boolean result;
-
     /**
      * Create a {@code BranchUtil} instance.
      *
@@ -239,4 +234,9 @@ public final class BranchUtil<T> {
         handle(ifHandler, null);
     }
 
+    /**
+     * The final result of the boolean expression.
+     */
+    private final boolean result;
+
 }

devkit-utils/src/main/java/cn/org/codecrafters/devkit/utils/ChainedCalcUtil.java

@@ -95,12 +95,6 @@ import java.util.function.Function;
 @Getter
 public final class ChainedCalcUtil {
 
-    /**
-     * -- GETTER --
-     * Returns the current value as a BigDecimal.
-     */
-    private BigDecimal value;
-
     /**
      * Creates a {@code ChainedCalcUtil} instance with the specified initial
      * value.
@@ -359,4 +353,10 @@ public final class ChainedCalcUtil {
         return res;
     }
 
+    /**
+     * -- GETTER --
+     * Returns the current value as a BigDecimal.
+     */
+    private BigDecimal value;
+
 }

devkit-utils/src/main/java/cn/org/codecrafters/devkit/utils/HashUtil.java

@@ -69,48 +69,6 @@ import java.util.Optional;
  */
 public final class HashUtil {
 
-    /**
-     * Private constructor to prevent instantiation
-     */
-    private HashUtil() {
-    }
-
-    /**
-     * Calculates the hash value of the specified string using the specified
-     * algorithm and charset.
-     *
-     * @param method  the hash algorithm to use
-     * @param value   the string to calculate the hash value for
-     * @param charset the charset to use for encoding the string (default is
-     *                UTF-8 if null)
-     * @return the hash value as a hexadecimal string, or an empty string if
-     * the algorithm is not available
-     * @throws RuntimeException if an unknown algorithm name is provided
-     *                          (should not occur under controlled usage)
-     */
-    private static String hash(String method, String value, Charset charset) {
-        try {
-            var messageDigest = MessageDigest.getInstance(method);
-            messageDigest.update(value.getBytes(charset));
-            var bytes = messageDigest.digest();
-            var builder = new StringBuilder();
-
-            for (var b : bytes) {
-                var str = Integer.toHexString(b & 0xff);
-                if (str.length() == 1) {
-                    builder.append(0);
-                }
-                builder.append(str);
-            }
-
-            return builder.toString();
-        } catch (NoSuchAlgorithmException ignored) {
-            // This should not occur under controlled usage
-            // Only trusted algorithms are allowed
-            return "";
-        }
-    }
-
     /**
      * Calculates the MD2 hash value of the specified string using the given
      * charset.
@@ -286,4 +244,46 @@ public final class HashUtil {
         return hash("SHA-512", value, StandardCharsets.UTF_8);
     }
 
+    /**
+     * Private constructor will protect this class from being instantiated.
+     */
+    private HashUtil() {
+    }
+
+    /**
+     * Calculates the hash value of the specified string using the specified
+     * algorithm and charset.
+     *
+     * @param method  the hash algorithm to use
+     * @param value   the string to calculate the hash value for
+     * @param charset the charset to use for encoding the string (default is
+     *                UTF-8 if null)
+     * @return the hash value as a hexadecimal string, or an empty string if
+     * the algorithm is not available
+     * @throws RuntimeException if an unknown algorithm name is provided
+     *                          (should not occur under controlled usage)
+     */
+    private static String hash(String method, String value, Charset charset) {
+        try {
+            var messageDigest = MessageDigest.getInstance(method);
+            messageDigest.update(value.getBytes(charset));
+            var bytes = messageDigest.digest();
+            var builder = new StringBuilder();
+
+            for (var b : bytes) {
+                var str = Integer.toHexString(b & 0xff);
+                if (str.length() == 1) {
+                    builder.append(0);
+                }
+                builder.append(str);
+            }
+
+            return builder.toString();
+        } catch (NoSuchAlgorithmException ignored) {
+            // This should not occur under controlled usage
+            // Only trusted algorithms are allowed
+            return "";
+        }
+    }
+
 }

devkit-utils/src/main/java/cn/org/codecrafters/devkit/utils/MapUtil.java

@@ -37,12 +37,6 @@ import java.util.Map;
 @Slf4j
 public final class MapUtil {
 
-    /**
-     * Private constructor to prevent instantiation of MapUtil.
-     */
-    private MapUtil() {
-    }
-
     /**
      * Converts an object to a map by mapping the field names to their
      * corresponding values.
@@ -219,4 +213,10 @@ public final class MapUtil {
             return String.valueOf(obj);
         }
     }
+
+    /**
+     * Private constructor will protect this class from being instantiated.
+     */
+    private MapUtil() {
+    }
 }

guid/src/main/java/cn/org/codecrafters/guid/impl/SnowflakeGuidCreator.java

@@ -15,13 +15,13 @@
  * limitations under the License.
  */
 
-package cn.org.codecrafters.guid;
+package cn.org.codecrafters.guid.impl;
 
+import cn.org.codecrafters.guid.GuidCreator;
 import cn.org.codecrafters.guid.exceptions.TimingException;
 
 import java.time.LocalDateTime;
 import java.time.ZoneId;
-import java.time.ZoneOffset;
 
 /**
  * The {@code SnowflakeGuidCreator} generates unique identifiers using the
@@ -49,48 +49,6 @@ import java.time.ZoneOffset;
  */
 public final class SnowflakeGuidCreator implements GuidCreator<Long> {
 
-    /**
-     * Default custom epoch.
-     *
-     * @value 2015-01-01T00:00:00Z
-     */
-    private static final long DEFAULT_CUSTOM_EPOCH = 1_420_070_400_000L;
-
-    /**
-     * The start epoch timestamp to generate IDs from.
-     */
-    private final long startEpoch;
-
-    /**
-     * The number of bits reserved for the worker ID.
-     */
-    private final long workerIdBits = 5L;
-
-    /**
-     * The number of bits reserved for the data centre ID.
-     */
-    private final long dataCentreIdBits = 5L;
-
-    /**
-     * The worker ID assigned to this generator.
-     */
-    private final long workerId;
-
-    /**
-     * The data centre ID assigned to this generator.
-     */
-    private final long dataCentreId;
-
-    /**
-     * The current sequence number.
-     */
-    private long sequence = 0L;
-
-    /**
-     * The timestamp of the last generated ID.
-     */
-    private long lastTimestamp = -1L;
-
     /**
      * Constructs a SnowflakeGuidGenerator with the default start epoch and
      * custom worker ID, data centre ID.
@@ -204,5 +162,48 @@ public final class SnowflakeGuidCreator implements GuidCreator<Long> {
     private long currentTimestamp() {
         return LocalDateTime.now().atZone(ZoneId.systemDefault()).toInstant().toEpochMilli();
     }
+
+    /**
+     * Default custom epoch.
+     *
+     * @value 2015-01-01T00:00:00Z
+     */
+    private static final long DEFAULT_CUSTOM_EPOCH = 1_420_070_400_000L;
+
+    /**
+     * The start epoch timestamp to generate IDs from.
+     */
+    private final long startEpoch;
+
+    /**
+     * The number of bits reserved for the worker ID.
+     */
+    private final long workerIdBits = 5L;
+
+    /**
+     * The number of bits reserved for the data centre ID.
+     */
+    private final long dataCentreIdBits = 5L;
+
+    /**
+     * The worker ID assigned to this generator.
+     */
+    private final long workerId;
+
+    /**
+     * The data centre ID assigned to this generator.
+     */
+    private final long dataCentreId;
+
+    /**
+     * The current sequence number.
+     */
+    private long sequence = 0L;
+
+    /**
+     * The timestamp of the last generated ID.
+     */
+    private long lastTimestamp = -1L;
+
 }
 

property-guard-spring-boot-starter/src/main/java/cn/org/codecrafters/propertyguard/autoconfiguration/PropertyGuard.java

@@ -70,8 +70,6 @@ import java.util.Optional;
  */
 public class PropertyGuard implements EnvironmentPostProcessor {
 
-    private final String PREFIX = "pg";
-
     /**
      * Process the encryption environment variables.
      *
@@ -108,4 +106,6 @@ public class PropertyGuard implements EnvironmentPostProcessor {
             }
         }
     }
+
+    private static final String PREFIX = "pg";
 }

simple-jwt-authzero/src/main/java/cn/org/codecrafters/simplejwt/authzero/AuthzeroTokenResolver.java

@@ -104,34 +104,6 @@ import java.util.*;
 @Slf4j
 public class AuthzeroTokenResolver implements TokenResolver<DecodedJWT> {
 
-    /**
-     * GuidCreator used for generating unique identifiers for "jti" claim in
-     * JWT tokens.
-     */
-    private final GuidCreator<?> jtiCreator;
-
-    /**
-     * The algorithm used for signing and verifying JWT tokens.
-     */
-    private final Algorithm algorithm;
-
-    /**
-     * The issuer claim value to be included in JWT tokens.
-     */
-    private final String issuer;
-
-    /**
-     * The JSON Web Token resolver.
-     */
-    private final JWTVerifier verifier;
-
-    /**
-     * Jackson JSON handler.
-     */
-    private final ObjectMapper objectMapper;
-
-    private final AuthzeroTokenResolverConfig config = AuthzeroTokenResolverConfig.getInstance();
-
     /**
      * Creates a new instance of {@code AuthzeroTokenResolver} with the
      * provided configurations.
@@ -150,7 +122,7 @@ public class AuthzeroTokenResolver implements TokenResolver<DecodedJWT> {
             throw new IllegalArgumentException("A secret is required to build a JSON Web Token.");
         }
 
-        if (secret.length() <= 32) {
+        if (secret.length() < 32) {
             log.warn("The provided secret which owns {} characters is too weak. Please consider replacing it with a stronger one.", secret.length());
         }
 
@@ -224,104 +196,6 @@ public class AuthzeroTokenResolver implements TokenResolver<DecodedJWT> {
         log.info("The secret has been set to {}.", secret);
     }
 
-    /**
-     * Builds the basic information of the JSON Web Token (JWT) using the
-     * provided parameters and adds it to the JWTCreator.Builder.
-     *
-     * @param subject     the subject claim value to be included in the JWT
-     * @param audience    an array of audience claim values to be included in
-     *                    the JWT
-     * @param expireAfter the duration after which the JWT will expire
-     * @param builder     the JWTCreator.Builder instance to which the basic
-     *                    information will be added
-     */
-    private void buildBasicInfo(JWTCreator.Builder builder, Duration expireAfter, String subject, String... audience) {
-        var now = LocalDateTime.now();
-
-        // bind issuer (iss)
-        builder.withIssuer(issuer);
-        // bind issued at (iat)
-        builder.withIssuedAt(Date.from(now.atZone(ZoneId.systemDefault()).toInstant()));
-        // bind not before (nbf)
-        builder.withNotBefore(Date.from(now.atZone(ZoneId.systemDefault()).toInstant()));
-        // bind audience (aud)
-        builder.withAudience(audience);
-        // bind subject (sub)
-        builder.withSubject(subject);
-        // bind expire at (exp)
-        builder.withExpiresAt(Date.from(now.plus(expireAfter).atZone(ZoneId.systemDefault()).toInstant()));
-        // bind JWT Id (jti)
-        builder.withJWTId(jtiCreator.nextId().toString());
-    }
-
-    /**
-     * Add a claim to a builder.
-     *
-     * @param builder the builder to build this JSON Web Token
-     * @param name    the property name
-     * @param value   the property value
-     */
-    private void addClaim(JWTCreator.Builder builder, String name, Object value) {
-        if (Objects.nonNull(value)) {
-            if (value instanceof Boolean v) {
-                builder.withClaim(name, v);
-            } else if (value instanceof Double v) {
-                builder.withClaim(name, v);
-            } else if (value instanceof Float v) {
-                builder.withClaim(name, v.doubleValue());
-            } else if (value instanceof Integer v) {
-                builder.withClaim(name, v);
-            } else if (value instanceof Long v) {
-                builder.withClaim(name, v);
-            } else if (value instanceof String v) {
-                builder.withClaim(name, v);
-            } else if (value instanceof Date v) {
-                builder.withClaim(name, v);
-            } else if (value instanceof List<?> v) {
-                builder.withClaim(name, v);
-            } else {
-                log.warn("""
-                        Unable to determine the type of field {}, we will handle it as a String.""", name);
-                builder.withClaim(name, value.toString());
-            }
-        } else {
-            builder.withNullClaim(name);
-        }
-    }
-
-    /**
-     * Builds the custom claims of the JSON Web Token (JWT) using the provided
-     * Map of claims and adds them to the JWTCreator.Builder.
-     * <p>
-     * This method is used to add custom claims to the JWT. It takes a Map of
-     * claims, where each entry represents a custom claim name (key) and its
-     * corresponding value (value). The custom claims will be added to the JWT
-     * using the JWTCreator.Builder.
-     *
-     * @param claims  a Map containing the custom claims to be added to the JWT
-     * @param builder the JWTCreator.Builder instance to which the custom
-     *                claims will be added
-     */
-    private void buildMapClaims(JWTCreator.Builder builder, Map<String, Object> claims) {
-        if (Objects.nonNull(claims)) {
-            for (var e : claims.entrySet()) {
-                addClaim(builder, e.getKey(), e.getValue());
-            }
-        }
-    }
-
-    /**
-     * Finish creating a token.
-     * <p>
-     * This is the final step of create a token, to sign this token.
-     *
-     * @param builder the builder to build this JWT
-     * @return the generated token as a {@code String}
-     */
-    private String buildToken(JWTCreator.Builder builder) {
-        return builder.sign(algorithm);
-    }
-
     /**
      * Creates a new token with the specified expiration duration, subject, and
      * audience.
@@ -552,8 +426,137 @@ public class AuthzeroTokenResolver implements TokenResolver<DecodedJWT> {
         return renew(oldToken, Duration.ofMinutes(30), payload);
     }
 
+    /**
+     * Builds the basic information of the JSON Web Token (JWT) using the
+     * provided parameters and adds it to the JWTCreator.Builder.
+     *
+     * @param subject     the subject claim value to be included in the JWT
+     * @param audience    an array of audience claim values to be included in
+     *                    the JWT
+     * @param expireAfter the duration after which the JWT will expire
+     * @param builder     the JWTCreator.Builder instance to which the basic
+     *                    information will be added
+     */
+    private void buildBasicInfo(JWTCreator.Builder builder, Duration expireAfter, String subject, String... audience) {
+        var now = LocalDateTime.now();
+
+        // bind issuer (iss)
+        builder.withIssuer(issuer);
+        // bind issued at (iat)
+        builder.withIssuedAt(Date.from(now.atZone(ZoneId.systemDefault()).toInstant()));
+        // bind not before (nbf)
+        builder.withNotBefore(Date.from(now.atZone(ZoneId.systemDefault()).toInstant()));
+        // bind audience (aud)
+        builder.withAudience(audience);
+        // bind subject (sub)
+        builder.withSubject(subject);
+        // bind expire at (exp)
+        builder.withExpiresAt(Date.from(now.plus(expireAfter).atZone(ZoneId.systemDefault()).toInstant()));
+        // bind JWT Id (jti)
+        builder.withJWTId(jtiCreator.nextId().toString());
+    }
+
+    /**
+     * Add a claim to a builder.
+     *
+     * @param builder the builder to build this JSON Web Token
+     * @param name    the property name
+     * @param value   the property value
+     */
+    private void addClaim(JWTCreator.Builder builder, String name, Object value) {
+        if (Objects.nonNull(value)) {
+            if (value instanceof Boolean v) {
+                builder.withClaim(name, v);
+            } else if (value instanceof Double v) {
+                builder.withClaim(name, v);
+            } else if (value instanceof Float v) {
+                builder.withClaim(name, v.doubleValue());
+            } else if (value instanceof Integer v) {
+                builder.withClaim(name, v);
+            } else if (value instanceof Long v) {
+                builder.withClaim(name, v);
+            } else if (value instanceof String v) {
+                builder.withClaim(name, v);
+            } else if (value instanceof Date v) {
+                builder.withClaim(name, v);
+            } else if (value instanceof List<?> v) {
+                builder.withClaim(name, v);
+            } else {
+                log.warn("""
+                        Unable to determine the type of field {}, we will handle it as a String.""", name);
+                builder.withClaim(name, value.toString());
+            }
+        } else {
+            builder.withNullClaim(name);
+        }
+    }
+
+    /**
+     * Builds the custom claims of the JSON Web Token (JWT) using the provided
+     * Map of claims and adds them to the JWTCreator.Builder.
+     * <p>
+     * This method is used to add custom claims to the JWT. It takes a Map of
+     * claims, where each entry represents a custom claim name (key) and its
+     * corresponding value (value). The custom claims will be added to the JWT
+     * using the JWTCreator.Builder.
+     *
+     * @param claims  a Map containing the custom claims to be added to the JWT
+     * @param builder the JWTCreator.Builder instance to which the custom
+     *                claims will be added
+     */
+    private void buildMapClaims(JWTCreator.Builder builder, Map<String, Object> claims) {
+        if (Objects.nonNull(claims)) {
+            for (var e : claims.entrySet()) {
+                addClaim(builder, e.getKey(), e.getValue());
+            }
+        }
+    }
+
+    /**
+     * Finish creating a token.
+     * <p>
+     * This is the final step of create a token, to sign this token.
+     *
+     * @param builder the builder to build this JWT
+     * @return the generated token as a {@code String}
+     */
+    private String buildToken(JWTCreator.Builder builder) {
+        return builder.sign(algorithm);
+    }
+
+    /**
+     * Default type reference for Map.
+     */
     private static class MapTypeReference extends TypeReference<Map<String, Object>> {
         MapTypeReference() {
         }
     }
+
+    /**
+     * GuidCreator used for generating unique identifiers for "jti" claim in
+     * JWT tokens.
+     */
+    private final GuidCreator<?> jtiCreator;
+
+    /**
+     * The algorithm used for signing and verifying JWT tokens.
+     */
+    private final Algorithm algorithm;
+
+    /**
+     * The issuer claim value to be included in JWT tokens.
+     */
+    private final String issuer;
+
+    /**
+     * The JSON Web Token resolver.
+     */
+    private final JWTVerifier verifier;
+
+    /**
+     * Jackson JSON handler.
+     */
+    private final ObjectMapper objectMapper;
+
+    private final AuthzeroTokenResolverConfig config = AuthzeroTokenResolverConfig.getInstance();
 }

simple-jwt-authzero/src/main/java/cn/org/codecrafters/simplejwt/authzero/config/AuthzeroTokenResolverConfig.java

@@ -62,42 +62,6 @@ import java.util.function.Function;
  */
 public final class AuthzeroTokenResolverConfig implements TokenResolverConfig<Function<String, Algorithm>> {
 
-    /**
-     * Constructs a new instance of {@code AuthzeroTokenResolverConfig}.
-     * <p>
-     * The constructor is set as private to enforce the singleton pattern for
-     * this configuration class. Instances of
-     * {@code AuthzeroTokenResolverConfig} should be obtained through the
-     * {@link #getInstance()} method.
-     */
-    private AuthzeroTokenResolverConfig() {
-    }
-
-    /**
-     * The singleton instance of {@code AuthzeroTokenResolverConfig}.
-     * <p>
-     * This instance is used to ensure that only one instance of
-     * {@code AuthzeroTokenResolverConfig} is created and shared throughout the
-     * application. The singleton pattern is implemented to provide centralised
-     * configuration and avoid redundant object creation.
-     */
-    private static AuthzeroTokenResolverConfig instance;
-
-    /**
-     * The supported algorithms and their corresponding algorithm functions.
-     * <p>
-     * This map stores the supported algorithms as keys and their corresponding
-     * algorithm functions as values. The algorithm functions represent the
-     * functions used by the {@code com.auth0:java-jwt} library to handle the
-     * specific algorithms. The mapping is used to provide proper algorithm
-     * resolution and processing within the {@link AuthzeroTokenResolver}.
-     */
-    private static final Map<TokenAlgorithm, Function<String, Algorithm>> SUPPORTED_ALGORITHMS = new HashMap<>() {{
-        put(TokenAlgorithm.HS256, Algorithm::HMAC256);
-        put(TokenAlgorithm.HS384, Algorithm::HMAC384);
-        put(TokenAlgorithm.HS512, Algorithm::HMAC512);
-    }};
-
     /**
      * Gets the instance of {@code AuthzeroTokenResolverConfig}.
      * <p>
@@ -140,4 +104,40 @@ public final class AuthzeroTokenResolverConfig implements TokenResolverConfig<Fu
         return Optional.of(SUPPORTED_ALGORITHMS).map((entry) -> entry.get(algorithm))
                 .orElseThrow(() -> new UnsupportedAlgorithmException("The specified algorithm is not supported yet."));
     }
+
+    /**
+     * Constructs a new instance of {@code AuthzeroTokenResolverConfig}.
+     * <p>
+     * The constructor is set as private to enforce the singleton pattern for
+     * this configuration class. Instances of
+     * {@code AuthzeroTokenResolverConfig} should be obtained through the
+     * {@link #getInstance()} method.
+     */
+    private AuthzeroTokenResolverConfig() {
+    }
+
+    /**
+     * The singleton instance of {@code AuthzeroTokenResolverConfig}.
+     * <p>
+     * This instance is used to ensure that only one instance of
+     * {@code AuthzeroTokenResolverConfig} is created and shared throughout the
+     * application. The singleton pattern is implemented to provide centralised
+     * configuration and avoid redundant object creation.
+     */
+    private static AuthzeroTokenResolverConfig instance;
+
+    /**
+     * The supported algorithms and their corresponding algorithm functions.
+     * <p>
+     * This map stores the supported algorithms as keys and their corresponding
+     * algorithm functions as values. The algorithm functions represent the
+     * functions used by the {@code com.auth0:java-jwt} library to handle the
+     * specific algorithms. The mapping is used to provide proper algorithm
+     * resolution and processing within the {@link AuthzeroTokenResolver}.
+     */
+    private static final Map<TokenAlgorithm, Function<String, Algorithm>> SUPPORTED_ALGORITHMS = new HashMap<>() {{
+        put(TokenAlgorithm.HS256, Algorithm::HMAC256);
+        put(TokenAlgorithm.HS384, Algorithm::HMAC384);
+        put(TokenAlgorithm.HS512, Algorithm::HMAC512);
+    }};
 }