# AccessControlUtils.java

    /*
     * Copyright (c) 2024, WSO2 LLC. (http://www.wso2.com).
     *
     * WSO2 LLC. licenses this file to you 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 org.apache.synapse.mediators.bsf.access.control;

    import org.apache.synapse.mediators.bsf.access.control.config.AccessControlConfig;
    import org.apache.synapse.mediators.bsf.access.control.config.AccessControlListType;

    import java.util.Comparator;
    import java.util.List;

    /**
     * Utility methods related to Script Mediator access control.
     */
    public class AccessControlUtils {

        /**
         * Returns whether the provided string which represents a Java class or native object is accessible or not.
         * The allowing/blocking will be determined by the provided AccessControlConfig, based on the matching/comparing
         * done as specified in the comparator.
         * @param string                Java class name or native object name.
         * @param accessControlConfig   Access control config of the Script Mediator.
         * @param comparator            The comparator based on which, the provided Java class/native object name is
         *                              matched against the provided access control config.
         * @return                      Whether the access is allowed or not.
         */
        public static boolean isAccessAllowed(String string, AccessControlConfig accessControlConfig,
                                              Comparator<String> comparator) {
            if (accessControlConfig == null || !accessControlConfig.isAccessControlEnabled()) {
                return true; // Access control is not applicable
            }

            List<String> accessControlList = accessControlConfig.getAccessControlList();
            boolean doesMatchExist = false;
            for (String item : accessControlList) {
                if (comparator.compare(string, item) > -1) {
                    doesMatchExist = true;
                    break;
                }
            }

            if (accessControlConfig.getAccessControlListType() == AccessControlListType.BLOCK_LIST) {
                return !doesMatchExist;
            }
            if (accessControlConfig.getAccessControlListType() == AccessControlListType.ALLOW_LIST) {
                return doesMatchExist;
            }
            return true; // Ideally we won't reach here
        }
    }