001/*
002 * nimbus-jose-jwt
003 *
004 * Copyright 2012-2016, Connect2id Ltd and contributors.
005 *
006 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use
007 * this file except in compliance with the License. You may obtain a copy of the
008 * License at
009 *
010 *    http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software distributed
013 * under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
014 * CONDITIONS OF ANY KIND, either express or implied. See the License for the
015 * specific language governing permissions and limitations under the License.
016 */
017
018package com.nimbusds.jose.crypto.impl;
019
020import com.nimbusds.jose.JOSEException;
021import com.nimbusds.jose.JWEAlgorithm;
022import com.nimbusds.jose.JWEHeader;
023
024
025/**
026 * JWE header validation.
027 *
028 * @author Vladimir Dzhuvinov
029 * @version 2023-09-10
030 */
031public class JWEHeaderValidation {
032
033
034        /**
035         * Gets the JWE algorithm of the specified header and ensure it is not
036         * {@code null}.
037         *
038         * @param jweHeader The JWE header. Must not be {@code null}.
039         *
040         * @return The JWE algorithm.
041         *
042         * @throws JOSEException If the JWE {@code alg} header parameter is
043         *                       {@code null}.
044         */
045        public static JWEAlgorithm getAlgorithmAndEnsureNotNull(final JWEHeader jweHeader)
046                throws JOSEException {
047
048                JWEAlgorithm alg = jweHeader.getAlgorithm();
049                if (alg == null) {
050                        throw new JOSEException("The algorithm \"alg\" header parameter must not be null");
051                }
052                return alg;
053        }
054
055
056        private JWEHeaderValidation() {}
057}