public AuthToken decodeFromString()

in kerby-provider/token-provider/src/main/java/org/apache/kerby/kerberos/provider/token/JwtTokenDecoder.java [74:139]
62 lines of code
16 McCabe index (conditional complexity)

    public AuthToken decodeFromString(String content) throws IOException {
       JWT jwt = null;
        try {
            jwt = JWTParser.parse(content);
        } catch (ParseException e) {
            // Invalid JWT encoding
            throw new IOException("Failed to parse JWT token string", e);
        }

        // Check the JWT type
        if (jwt instanceof PlainJWT) {
            PlainJWT plainObject = (PlainJWT) jwt;
            try {

                if (verifyToken(jwt)) {
                    return new JwtAuthToken(plainObject.getJWTClaimsSet());
                } else {
                    return null;
                }
            } catch (ParseException e) {
                throw new IOException("Failed to get JWT claims set", e);
            }
        } else if (jwt instanceof EncryptedJWT) {
            EncryptedJWT encryptedJWT = (EncryptedJWT) jwt;
            decryptEncryptedJWT(encryptedJWT);
            SignedJWT signedJWT = encryptedJWT.getPayload().toSignedJWT();
            if (signedJWT != null) {
                boolean success = verifySignedJWT(signedJWT) && verifyToken(signedJWT);
                if (success) {
                    try {
                        signed = true;
                        return new JwtAuthToken(signedJWT.getJWTClaimsSet());
                    } catch (ParseException e) {
                        throw new IOException("Failed to get JWT claims set", e);
                    }
                } else {
                    return null;
                }
            } else {
                try {
                    if (verifyToken(encryptedJWT)) {
                        return new JwtAuthToken(encryptedJWT.getJWTClaimsSet());
                    } else {
                        return null;
                    }
                } catch (ParseException e) {
                    throw new IOException("Failed to get JWT claims set", e);
                }
            }
        } else if (jwt instanceof SignedJWT) {
            SignedJWT signedJWT = (SignedJWT) jwt;
            boolean success = verifySignedJWT(signedJWT) && verifyToken(signedJWT);
            if (success) {
                try {
                    signed = true;
                    return new JwtAuthToken(signedJWT.getJWTClaimsSet());
                } catch (ParseException e) {
                    throw new IOException("Failed to get JWT claims set", e);
                }
            } else {
                return null;
            }
        } else {
            throw new IOException("Unexpected JWT type: " + jwt);
        }
    }