docs: added Javadoc

simple-jwt/src/main/java/com/onixbyte/jwt/TokenCreator.java

@@ -18,10 +18,29 @@
 package com.onixbyte.jwt;
 
 /**
+ * Interface for creating and signing JSON Web Tokens (JWTs).
+ * <p>
+ * Defines a contract for implementations that generate signed JWTs from a given payload. The
+ * resulting token is typically a string in the format "header.payload.signature", where the
+ * signature is created using a cryptographic algorithm specific to the implementation.
  *
+ * @author zihluwang
  */
 public interface TokenCreator {
 
+    /**
+     * Signs a token payload to create a JWT.
+     * <p>
+     * Takes a {@link TokenPayload} object, serialises its claims, and generates a signed
+     * JWT string. The specific signing algorithm (e.g., HMAC, RSA, ECDSA) depends on
+     * the implementation.
+     *
+     * @param payload the {@link TokenPayload} containing claims to include in the token
+     * @return the signed JWT as a string in the format "header.payload.signature"
+     * @throws IllegalArgumentException if the payload cannot be serialised to JSON due to invalid
+     *                                  data or structure, or if the signing process fails due to
+     *                                  configuration issues
+     */
     String sign(TokenPayload payload);
 
 }

simple-jwt/src/main/java/com/onixbyte/jwt/TokenManager.java

@@ -1,7 +1,47 @@
+/*
+ * Copyright (C) 2024-2025 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package com.onixbyte.jwt;
 
+/**
+ * Interface for managing JSON Web Tokens (JWTs) with support for signing, verification, and
+ * payload extraction.
+ * <p>
+ * Combines the functionality of {@link TokenCreator} for creating signed JWTs and
+ * {@link TokenResolver} for verifying and parsing them, while adding the ability to extract the
+ * payload as a custom type {@code T}. Implementations are expected to handle both token generation
+ * and resolution, providing a unified interface for JWT operations.
+ *
+ * @param <T> the type of object to which the token payload will be converted
+ * @author zihluwang
+ */
 public interface TokenManager<T> extends TokenCreator, TokenResolver {
 
+    /**
+     * Extracts the payload from a JWT and converts it to an object of type {@code T}.
+     * <p>
+     * Retrieves the payload from the token and transforms it into the specified type using an
+     * implementation-specific mechanism, such as an adapter or mapper.
+     *
+     * @param token the JWT string from which to extract the payload
+     * @return the payload converted to an object of type {@code T}
+     * @throws IllegalArgumentException if the token is malformed, the signature is invalid, or the
+     *                                  payload cannot be deserialised or converted to
+     *                                  type {@code T}
+     */
     T extract(String token);
-
+}
-}

simple-jwt/src/main/java/com/onixbyte/jwt/TokenPayload.java

@@ -24,57 +24,158 @@ import java.time.ZoneId;
 import java.util.*;
 
 /**
+ * A builder-style class for constructing JSON Web Token (JWT) payloads.
+ * <p>
+ * Provides a fluent interface to set standard registered claims (e.g., subject, issuer, audience)
+ * and custom claims for a JWT payload. The class supports chaining method calls to build the
+ * payload incrementally, which can then be retrieved as a map for use in JWT creation. Ensures that
+ * registered claims are set using dedicated methods to prevent misuse.
  *
+ * @author zihluwang
  */
 public class TokenPayload {
 
+    /**
+     * Creates a new instance of {@link TokenPayload} with an empty payload.
+     * <p>
+     * Initialises the payload with empty collections for claims and audiences, ready for
+     * configuration via the builder methods.
+     *
+     * @return a new {@link TokenPayload} instance
+     */
     public static TokenPayload createPayload() {
         return new TokenPayload();
     }
 
+    /**
+     * The map storing custom claims for the JWT payload.
+     */
     private final Map<String, Object> payload;
+
+    /**
+     * The list of audience identifiers for the JWT.
+     */
     private final List<String> audiences;
 
+    /**
+     * The subject of the JWT, identifying the principal.
+     */
     private String subject;
+
+    /**
+     * The issuer of the JWT, identifying the entity that issued the token.
+     */
     private String issuer;
+
+    /**
+     * The unique identifier for the JWT.
+     */
     private String tokenId;
+
+    /**
+     * The expiration time of the JWT, as seconds since the Unix epoch.
+     */
     private Long expiresAt;
+
+    /**
+     * The time before which the JWT must not be accepted, as seconds since the Unix epoch.
+     */
     private Long notBefore;
+
+    /**
+     * The issuance time of the JWT, as seconds since the Unix epoch.
+     */
     private Long issuedAt;
 
     /**
-     * Private constructor to prevent instantiation of this utility class.
+     * Private constructor to enforce use of the factory method.
+     * <p>
+     * Initialises the internal collections for storing claims and audiences, preventing direct
+     * instantiation outside the class.
      */
     private TokenPayload() {
         payload = new HashMap<>();
         audiences = new ArrayList<>();
     }
 
+    /**
+     * Adds a single audience to the JWT payload.
+     * <p>
+     * Appends the specified audience identifier to the list of audiences, allowing the token to be
+     * validated for multiple recipients.
+     *
+     * @param audience the audience identifier to add
+     * @return this {@link TokenPayload} instance for method chaining
+     */
     public TokenPayload withAudience(String audience) {
         audiences.add(audience);
         return this;
     }
 
+    /**
+     * Adds multiple audiences to the JWT payload.
+     * <p>
+     * Appends all provided audience identifiers to the list of audiences, enabling the token to be
+     * validated for multiple recipients.
+     *
+     * @param audiences the audience identifiers to add
+     * @return this {@link TokenPayload} instance for method chaining
+     */
     public TokenPayload withAudiences(String... audiences) {
         this.audiences.addAll(Arrays.asList(audiences));
         return this;
     }
 
+    /**
+     * Sets the subject of the JWT payload.
+     * <p>
+     * Specifies the principal that is the subject of the token, typically identifying the user or
+     * entity the token represents.
+     *
+     * @param subject the subject identifier
+     * @return this {@link TokenPayload} instance for method chaining
+     */
     public TokenPayload withSubject(String subject) {
         this.subject = subject;
         return this;
     }
 
+    /**
+     * Sets the issuer of the JWT payload.
+     * <p>
+     * Specifies the entity that issued the token, allowing recipients to verify the token's origin.
+     *
+     * @param issuer the issuer identifier
+     * @return this {@link TokenPayload} instance for method chaining
+     */
     public TokenPayload withIssuer(String issuer) {
         this.issuer = issuer;
         return this;
     }
 
+    /**
+     * Sets the unique identifier for the JWT payload.
+     * <p>
+     * Assigns a unique token ID to the JWT, which can be used to prevent token reuse or for
+     * tracking purposes.
+     *
+     * @param tokenId the unique token identifier
+     * @return this {@link TokenPayload} instance for method chaining
+     */
     public TokenPayload withTokenId(String tokenId) {
         this.tokenId = tokenId;
         return this;
     }
 
+    /**
+     * Sets the expiration time for the JWT payload.
+     * <p>
+     * Specifies when the token expires, converted to seconds since the Unix epoch based on the
+     * system's default time zone.
+     *
+     * @param expiresAt the expiration time as a {@link LocalDateTime}
+     * @return this {@link TokenPayload} instance for method chaining
+     */
     public TokenPayload withExpiresAt(LocalDateTime expiresAt) {
         this.expiresAt = expiresAt.atZone(ZoneId.systemDefault())
                 .toInstant()
@@ -82,6 +183,15 @@ public class TokenPayload {
         return this;
     }
 
+    /**
+     * Sets the time before which the JWT must not be accepted.
+     * <p>
+     * Specifies the "not before" time, converted to seconds since the Unix epoch based on the
+     * system's default time zone.
+     *
+     * @param notBefore the time before which the token is invalid, as a {@link LocalDateTime}
+     * @return this {@link TokenPayload} instance for method chaining
+     */
     public TokenPayload withNotBefore(LocalDateTime notBefore) {
         this.notBefore = notBefore.atZone(ZoneId.systemDefault())
                 .toInstant()
@@ -89,6 +199,15 @@ public class TokenPayload {
         return this;
     }
 
+    /**
+     * Sets the issuance time for the JWT payload.
+     * <p>
+     * Specifies when the token was issued, converted to seconds since the Unix epoch based on the
+     * system's default time zone.
+     *
+     * @param issuedAt the issuance time as a {@link LocalDateTime}
+     * @return this {@link TokenPayload} instance for method chaining
+     */
     public TokenPayload withIssuedAt(LocalDateTime issuedAt) {
         this.issuedAt = issuedAt.atZone(ZoneId.systemDefault())
                 .toInstant()
@@ -96,6 +215,17 @@ public class TokenPayload {
         return this;
     }
 
+    /**
+     * Adds a custom claim to the JWT payload.
+     * <p>
+     * Stores a custom key-value pair in the payload, provided the key is not a registered claim.
+     * Registered claims must be set using their dedicated methods to ensure proper handling.
+     *
+     * @param name  the name of the custom claim
+     * @param value the value of the custom claim
+     * @return this {@link TokenPayload} instance for method chaining
+     * @throws IllegalStateException if the claim name is a registered claim
+     */
     public TokenPayload withClaim(String name, String value) {
         if (RegisteredClaims.VALUES.contains(name)) {
             throw new IllegalStateException("Please set registered claims with pre-defined methods");
@@ -105,10 +235,26 @@ public class TokenPayload {
         return this;
     }
 
+    /**
+     * Checks if the JWT payload has a valid issuer.
+     * <p>
+     * Returns {@code true} if the issuer is non-null and not blank, indicating that an issuer has
+     * been set.
+     *
+     * @return {@code true} if an issuer is set, {@code false} otherwise
+     */
     public boolean hasIssuer() {
         return Objects.nonNull(issuer) && !issuer.isBlank();
     }
 
+    /**
+     * Retrieves the complete JWT payload as a map.
+     * <p>
+     * Constructs a map containing all custom claims, registered claims (if set), and audiences.
+     * Only non-empty or non-blank values are included to ensure a clean payload.
+     *
+     * @return a map containing the JWT payload
+     */
     public Map<String, Object> getPayload() {
         var _payload = new HashMap<>(payload);
 
@@ -128,7 +274,7 @@ public class TokenPayload {
                 .ifPresent((jti) -> _payload.put(RegisteredClaims.TOKEN_ID, jti));
 
         Optional.ofNullable(issuer)
-                .map((iss) -> !iss.isBlank())
+                .filter((iss) -> !iss.isBlank())
                 .ifPresent((iss) -> _payload.put(RegisteredClaims.ISSUER, iss));
 
         Optional.ofNullable(issuedAt)
@@ -139,5 +285,4 @@ public class TokenPayload {
 
         return _payload;
     }
-
 }

simple-jwt/src/main/java/com/onixbyte/jwt/TokenResolver.java

@@ -23,16 +23,23 @@ import com.onixbyte.jwt.data.RawTokenComponent;
 import java.util.Map;
 
 /**
+ * Interface for resolving and verifying JSON Web Tokens (JWTs).
+ * <p>
+ * Defines a contract for implementations that parse, verify, and extract components from JWTs.
+ * Provides methods to validate the token's signature, retrieve its header and payload, and split it
+ * into raw components. Implementations are expected to handle cryptographic verification and JSON
+ * deserialisation specific to their signing algorithm.
  *
+ * @author zihluwang
  */
 public interface TokenResolver {
 
     /**
-     * Verifies the HMAC signature of the provided JWT.
+     * Verifies the signature of the provided JWT.
      * <p>
-     * Splits the token into its components and uses the configured algorithm and secret to check
+     * Splits the token into its components and checks the signature's validity using the
-     * the signature's validity. If the signature does not match, an exception is thrown by the
+     * implementation's configured algorithm and key. If the signature does not match, an exception
-     * underlying cryptographic utility.
+     * is thrown.
      *
      * @param token the JWT string to verify
      * @throws IllegalArgumentException if the token is malformed or the signature verification
@@ -68,6 +75,9 @@ public interface TokenResolver {
 
     /**
      * Splits a JWT into its raw components: header, payload, and signature.
+     * <p>
+     * Provides a default implementation that separates the token string into its three parts using
+     * dot separators and returns them as a {@link RawTokenComponent}.
      *
      * @param token the JWT string to split
      * @return a {@link RawTokenComponent} containing the header, payload, and signature as strings

simple-jwt/src/main/java/com/onixbyte/jwt/constant/Algorithm.java

@@ -18,7 +18,14 @@
 package com.onixbyte.jwt.constant;
 
 /**
+ * Enumeration of cryptographic algorithms supported for JSON Web Token (JWT) signing
+ * and verification.
+ * <p>
+ * Defines a set of recognised algorithms including HMAC (HS*), RSA (RS*), and ECDSA (ES*) variants,
+ * each with a specific SHA length (256, 384, or 512 bits). Provides methods to identify the
+ * algorithm type and retrieve its properties.
  *
+ * @author zihluwang
  */
 public enum Algorithm {
     HS256(1, 256, "HmacSHA256"),
@@ -32,32 +39,41 @@ public enum Algorithm {
     ES512(3, 512, "SHA512withECDSA");
 
     /**
-     *
+     * Bit flag indicating an HMAC-based algorithm.
      */
     private static final int HS_FLAG = 1; // 001
 
     /**
-     *
+     * Bit flag indicating an RSA-based algorithm.
      */
     private static final int RS_FLAG = 2; // 010
 
     /**
-     *
+     * Bit flag indicating an ECDSA-based algorithm.
      */
     private static final int ES_FLAG = 3; // 011
 
     /**
-     *
+     * The type flag identifying the algorithm family (HMAC, RSA, or ECDSA).
      */
     private final int typeFlag;
+
+    /**
+     * The length of the SHA hash in bits (256, 384, or 512).
+     */
     private final int shaLength;
+
+    /**
+     * The standard name of the algorithm as recognised by the Java Cryptography Architecture (JCA).
+     */
     private final String algorithm;
 
     /**
+     * Constructs an algorithm enum constant with the specified type flag, SHA length, and algorithm name.
      *
-     * @param typeFlag
+     * @param typeFlag  the bit flag identifying the algorithm type
-     * @param shaLength
+     * @param shaLength the length of the SHA hash in bits
-     * @param algorithm
+     * @param algorithm the JCA-compliant algorithm name
      */
     Algorithm(int typeFlag, int shaLength, String algorithm) {
         this.typeFlag = typeFlag;
@@ -66,48 +82,54 @@ public enum Algorithm {
     }
 
     /**
+     * Determines whether this algorithm is HMAC-based.
      *
-     * @return
+     * @return {@code true} if the algorithm uses HMAC (e.g., HS256, HS384, HS512), {@code false} otherwise
      */
     public boolean isHmac() {
         return (this.typeFlag & HS_FLAG) != 0;
     }
 
     /**
+     * Determines whether this algorithm is RSA-based.
      *
-     * @return
+     * @return {@code true} if the algorithm uses RSA (e.g., RS256, RS384, RS512), {@code false} otherwise
      */
     public boolean isRsa() {
         return (this.typeFlag & RS_FLAG) != 0;
     }
 
     /**
+     * Determines whether this algorithm is ECDSA-based.
      *
-     * @return
+     * @return {@code true} if the algorithm uses ECDSA (e.g., ES256, ES384, ES512), {@code false} otherwise
      */
     public boolean isEcdsa() {
         return (this.typeFlag & ES_FLAG) != 0;
     }
 
     /**
+     * Retrieves the SHA length of this algorithm in bits.
      *
-     * @return
+     * @return the SHA length (256, 384, or 512)
      */
     public int getShaLength() {
         return shaLength;
     }
 
     /**
+     * Retrieves the type flag of this algorithm.
      *
-     * @return
+     * @return the type flag (1 for HMAC, 2 for RSA, 3 for ECDSA)
      */
     public int getTypeFlag() {
         return typeFlag;
     }
 
     /**
+     * Retrieves the JCA-compliant name of this algorithm.
      *
-     * @return
+     * @return the algorithm name (e.g., "HmacSHA256", "SHA256withRSA")
      */
     public String getAlgorithm() {
         return algorithm;

simple-jwt/src/main/java/com/onixbyte/jwt/constant/HeaderClaims.java

@@ -17,6 +17,15 @@
 
 package com.onixbyte.jwt.constant;
 
+/**
+ * Utility class defining standard header claim names for JSON Web Tokens (JWTs).
+ * <p>
+ * Provides constants representing the recognised header claims as specified in the JWT standard.
+ * These claims are used in the header section of a JWT to describe its structure and cryptographic
+ * properties.
+ *
+ * @author zihluwang
+ */
 public final class HeaderClaims {
 
     /**

simple-jwt/src/main/java/com/onixbyte/jwt/constant/RegisteredClaims.java

@@ -20,7 +20,14 @@ package com.onixbyte.jwt.constant;
 import java.util.List;
 
 /**
+ * Utility class defining standard registered claim names for JSON Web Tokens (JWTs).
+ * <p>
+ * Provides constants representing the registered claims as defined in RFC 7519. These claims are
+ * used in the payload section of a JWT to convey metadata about the token, such as its issuer,
+ * subject, and validity period. All claims are optional but widely recognised in
+ * JWT implementations.
  *
+ * @author zihluwang
  */
 public final class RegisteredClaims {
 
@@ -73,6 +80,13 @@ public final class RegisteredClaims {
      */
     public static final String TOKEN_ID = "jti";
 
+    /**
+     * An immutable list of all registered claim names defined in this class.
+     * <p>
+     * Contains the values of {@link #ISSUER}, {@link #SUBJECT}, {@link #AUDIENCE},
+     * {@link #EXPIRES_AT}, {@link #NOT_BEFORE}, {@link #ISSUED_AT}, and {@link #TOKEN_ID} for
+     * convenient iteration or lookup.
+     */
     public static final List<String> VALUES = List.of(ISSUER, SUBJECT, AUDIENCE, EXPIRES_AT, NOT_BEFORE, ISSUED_AT, TOKEN_ID);
 
 }

simple-jwt/src/main/java/com/onixbyte/jwt/data/RawTokenComponent.java

@@ -18,10 +18,15 @@
 package com.onixbyte.jwt.data;
 
 /**
+ * A record representing the raw components of a JSON Web Token (JWT).
+ * <p>
+ * Holds the header, payload, and signature of a JWT as strings, typically in their Base64 URL-encoded
+ * form as extracted from a token string. This record is used to facilitate parsing and processing
+ * of JWTs without decoding or validating their contents.
  *
- * @param header
+ * @param header    the Base64 URL-encoded header string of the JWT
- * @param payload
+ * @param payload   the Base64 URL-encoded payload string of the JWT
- * @param signature
+ * @param signature the Base64 URL-encoded signature string of the JWT
  * @author zihluwang
  */
 public record RawTokenComponent(

simple-jwt/src/main/java/com/onixbyte/jwt/holder/ObjectMapperHolder.java

@@ -23,6 +23,16 @@ import com.fasterxml.jackson.databind.json.JsonMapper;
 
 import java.util.Objects;
 
+/**
+ * Singleton holder for a configured {@link ObjectMapper} instance.
+ * <p>
+ * Provides a thread-safe, lazily initialised singleton to manage a single {@link ObjectMapper}
+ * instance, configured to sort JSON properties alphabetically. This class is designed to ensure
+ * consistent JSON serialisation and deserialisation across the application, particularly for
+ * JSON Web Token (JWT) processing.
+ *
+ * @author zihluwang
+ */
 public class ObjectMapperHolder {
 
     private static ObjectMapperHolder HOLDER;
@@ -39,9 +49,12 @@ public class ObjectMapperHolder {
     }
 
     /**
-     * Get singleton instance.
+     * Retrieves the singleton instance of this holder.
+     * <p>
+     * Uses double-checked locking to ensure thread-safe, lazy initialisation of the singleton. If
+     * the instance has not been created, it is initialised in a synchronised block.
      *
-     * @return the {@code ObjectMapperHolder} instance
+     * @return the singleton {@link ObjectMapperHolder} instance
      */
     public static ObjectMapperHolder getInstance() {
         if (Objects.isNull(HOLDER)) {
@@ -55,9 +68,9 @@ public class ObjectMapperHolder {
     }
 
     /**
-     * Get Object
+     * Retrieves the configured {@link ObjectMapper} instance.
      *
-     * @return
+     * @return the {@link ObjectMapper} configured for alphabetical property sorting
      */
     public ObjectMapper getObjectMapper() {
         return objectMapper;

simple-jwt/src/main/java/com/onixbyte/jwt/impl/HmacTokenManager.java

@@ -1,3 +1,20 @@
+/*
+ * Copyright (C) 2024-2025 OnixByte.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package com.onixbyte.jwt.impl;
 
 import com.onixbyte.devkit.utils.MapUtil;
@@ -10,39 +27,116 @@ import com.onixbyte.jwt.constant.Algorithm;
 
 import java.util.Map;
 
+/**
+ * A generic token manager implementation for creating, verifying, and extracting data from
+ * HMAC-signed JSON Web Tokens (JWTs).
+ * <p>
+ * This class integrates an {@link HmacTokenCreator} for signing tokens and an
+ * {@link HmacTokenResolver} for verification and parsing, using a specified HMAC algorithm. It
+ * supports converting token payloads to a custom type {@code T} via an {@link ObjectMapAdapter}.
+ *
+ * @param <T> the type of object to which the token payload will be converted
+ * @author zihluwang
+ */
 public class HmacTokenManager<T> implements TokenManager<T> {
 
     private final TokenCreator tokenCreator;
     private final TokenResolver tokenResolver;
     private final ObjectMapAdapter<T> adapter;
 
+    /**
+     * Constructs an HMAC token manager with the specified algorithm, issuer, secret, and adapter.
+     * <p>
+     * Initialises the {@link TokenCreator} and {@link TokenResolver} with the provided HMAC
+     * algorithm and secret key, and associates an adapter for converting token payloads to the
+     * generic type {@code T}.
+     *
+     * @param algorithm the HMAC algorithm to use for signing and verification
+     * @param issuer    the issuer identifier to include in the token payload if not already present
+     * @param secret    the secret key as a string, used to sign and verify the HMAC signature
+     * @param adapter   the {@link ObjectMapAdapter} for converting payload maps to objects of
+     *                  type {@code T}
+     * @throws IllegalArgumentException if the secret key is too short for the specified algorithm
+     */
     public HmacTokenManager(Algorithm algorithm, String issuer, String secret, ObjectMapAdapter<T> adapter) {
         this.tokenCreator = new HmacTokenCreator(algorithm, issuer, secret);
         this.tokenResolver = new HmacTokenResolver(algorithm, secret);
         this.adapter = adapter;
     }
 
+    /**
+     * Extracts the payload from a JWT and converts it to an object of type {@code T}.
+     * <p>
+     * Retrieves the payload as a map and uses the configured {@link ObjectMapAdapter} to transform
+     * it into the desired type.
+     *
+     * @param token the JWT string from which to extract the payload
+     * @return the payload converted to an object of type {@code T}
+     * @throws IllegalArgumentException if the token is malformed, the signature is invalid, or the
+     *                                  payload cannot be deserialised
+     */
     @Override
     public T extract(String token) {
         var payloadMap = getPayload(token);
         return MapUtil.mapToObject(payloadMap, adapter);
     }
 
+    /**
+     * Signs a token payload to create a JWT.
+     * <p>
+     * Delegates to the {@link TokenCreator} to generate a signed JWT string from the
+     * provided payload.
+     *
+     * @param payload the {@link TokenPayload} containing claims to include in the token
+     * @return the signed JWT as a string in the format "header.payload.signature"
+     * @throws IllegalArgumentException if the payload cannot be serialised to JSON due to invalid
+     *                                  data or structure
+     */
     @Override
     public String sign(TokenPayload payload) {
         return tokenCreator.sign(payload);
     }
 
+    /**
+     * Verifies the validity of a JWT.
+     * <p>
+     * Delegates to the {@link TokenResolver} to check the token's signature and structure.
+     *
+     * @param token the JWT string to verify
+     * @throws IllegalArgumentException if the token is malformed or the signature
+     *                                  verification fails
+     */
     @Override
     public void verify(String token) {
         tokenResolver.verify(token);
     }
 
+    /**
+     * Retrieves the header claims from the provided JWT.
+     * <p>
+     * Decodes the Base64-encoded header and deserialises it into a map of strings.
+     *
+     * @param token the JWT string from which to extract the header
+     * @return a map containing the header claims as key-value pairs
+     * @throws IllegalArgumentException if the token is malformed or the header cannot be
+     *                                  deserialised due to invalid JSON format
+     */
     @Override
     public Map<String, String> getHeader(String token) {
         return tokenResolver.getHeader(token);
     }
 
+    /**
+     * Retrieves the payload claims from a JWT.
+     * <p>
+     * Delegates to the {@link TokenResolver} to extract and deserialise the payload into a map,
+     * excluding registered claims.
+     *
+     * @param token the JWT string from which to extract the payload
+     * @return a map containing the custom payload claims as key-value pairs
+     * @throws IllegalArgumentException if the token is malformed or the payload cannot
+     *                                  be deserialised
+     */
     @Override
     public Map<String, Object> getPayload(String token) {
         return tokenResolver.getPayload(token);

simple-jwt/src/main/java/com/onixbyte/jwt/impl/HmacTokenResolver.java

@@ -23,7 +23,6 @@ import com.fasterxml.jackson.databind.ObjectMapper;
 import com.onixbyte.jwt.TokenResolver;
 import com.onixbyte.jwt.constant.Algorithm;
 import com.onixbyte.jwt.constant.RegisteredClaims;
-import com.onixbyte.jwt.data.RawTokenComponent;
 import com.onixbyte.jwt.holder.ObjectMapperHolder;
 import com.onixbyte.jwt.util.CryptoUtil;