Class JWTVerifier

lib/src/main/java/com/auth0/jwt/JWTVerifier.java:26–500

The JWTVerifier class holds the verify method to assert that a given Token has not only a proper JWT format, but also its signature matches. This class is thread-safe. @see com.auth0.jwt.interfaces.JWTVerifier

 * @see com.auth0.jwt.interfaces.JWTVerifier
 */
public final class JWTVerifier implements com.auth0.jwt.interfaces.JWTVerifier {
    private final Algorithm algorithm;
    final List<ExpectedCheckHolder> expectedChecks;
    private final JWTParser parser;

    JWTVerifier(Algorithm algorithm, List<ExpectedCheckHolder> expectedChecks) {
        this.algorithm = algorithm;
        this.expectedChecks = Collections.unmodifiableList(expectedChecks);
        this.parser = new JWTParser();
    }

    /**
     * Initialize a {@link Verification} instance using the given Algorithm.
     *
     * @param algorithm the Algorithm to use on the JWT verification.
     * @return a {@link Verification} instance to configure.
     * @throws IllegalArgumentException if the provided algorithm is null.
     */
    static Verification init(Algorithm algorithm) throws IllegalArgumentException {
        return new BaseVerification(algorithm);
    }

    /**
     * {@link Verification} implementation that accepts all the expected Claim values for verification, and
     * builds a {@link com.auth0.jwt.interfaces.JWTVerifier} used to verify a JWT's signature and expected claims.
     *
     * Note that this class is <strong>not</strong> thread-safe. Calling {@link #build()} returns an instance of
     * {@link com.auth0.jwt.interfaces.JWTVerifier} which can be reused.
     */
    public static class BaseVerification implements Verification {
        private final Algorithm algorithm;
        private final List<ExpectedCheckHolder> expectedChecks;
        private long defaultLeeway;
        private final Map<String, Long> customLeeways;
        private boolean ignoreIssuedAt;
        private Clock clock;

        BaseVerification(Algorithm algorithm) throws IllegalArgumentException {
            if (algorithm == null) {
                throw new IllegalArgumentException("The Algorithm cannot be null.");
            }

            this.algorithm = algorithm;
            this.expectedChecks = new ArrayList<>();
            this.customLeeways = new HashMap<>();
            this.defaultLeeway = 0;
        }

        @Override
        public Verification withIssuer(String... issuer) {
            List<String> value = isNullOrEmpty(issuer) ? null : Arrays.asList(issuer);
            addCheck(RegisteredClaims.ISSUER, ((claim, decodedJWT) -> {
                if (verifyNull(claim, value)) {
                    return true;
                }
                if (value == null || !value.contains(claim.asString())) {
                    throw new IncorrectClaimException(
                            "The Claim 'iss' value doesn't match the required issuer.", RegisteredClaims.ISSUER, claim);