# BaseConfiguration.java

    /*
     *  Copyright (c) 2022, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
     *
     *  WSO2 Inc. 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.transport.netty.config;

    import org.apache.axis2.AxisFault;
    import org.apache.axis2.context.ConfigurationContext;
    import org.apache.axis2.transport.base.threads.WorkerPool;
    import org.apache.axis2.transport.base.threads.WorkerPoolFactory;
    import org.apache.http.protocol.HTTP;

    import java.util.ArrayList;
    import java.util.Arrays;
    import java.util.List;
    import java.util.Objects;

    /**
     * This class has common configurations for both sender and receiver.
     */
    public abstract class BaseConfiguration {

        protected ConfigurationContext configurationContext;
        /**
         * Weather User-Agent header coming from client should be preserved.
         */
        protected boolean preserveUserAgentHeader = false;
        /**
         * Weather Server header coming from server should be preserved.
         */
        protected boolean preserveServerHeader = true;
        /**
         * Http headers which should be preserved.
         */
        protected List<String> preserveHttpHeaders;
        /**
         * The thread pool for executing the messages passing through.
         */
        private WorkerPool workerPool;

        NettyConfiguration conf = NettyConfiguration.getInstance();

        public BaseConfiguration(ConfigurationContext configurationContext) {

            this.configurationContext = configurationContext;
        }

        public void build() throws AxisFault {

            workerPool = WorkerPoolFactory.getWorkerPool(
                    conf.getWorkerPoolCoreSize(),
                    conf.getWorkerPoolMaxSize(),
                    conf.getWorkerThreadKeepaliveSec(),
                    conf.getWorkerPoolQueueLen(),
                    NettyConfiguration.HTTP_WORKER_THREAD_GROUP_NAME,
                    NettyConfiguration.HTTP_WORKER_THREAD_ID);
        }

        /**
         * Check whether to preserve or not the given HTTP header.
         *
         * @param headerName HTTP header name to be checked for preserving status
         * @return preserving status of the given HTTP header
         */
        public boolean isPreserveHttpHeader(String headerName) {

            if (Objects.isNull(headerName) || Objects.isNull(preserveHttpHeaders) || preserveHttpHeaders.isEmpty()) {
                return false;
            }
            return preserveHttpHeaders.contains(headerName.toUpperCase());
        }

        /**
         * Populate preserve HTTP headers from comma separate string.
         *
         * @param preserveHeaders Comma separated preserve enableD HTTP headers
         */
        protected void populatePreserveHTTPHeaders(String preserveHeaders) {

            preserveHttpHeaders = new ArrayList<>();
            if (Objects.nonNull(preserveHeaders) && !preserveHeaders.isEmpty()) {
                String[] presHeaders = preserveHeaders.trim().toUpperCase().split(",");
                if (presHeaders.length > 0) {
                    preserveHttpHeaders.addAll(Arrays.asList(presHeaders));
                }
            }

            if (preserveServerHeader && !preserveHttpHeaders.contains(HTTP.SERVER_HEADER.toUpperCase())) {
                preserveHttpHeaders.add(HTTP.SERVER_HEADER.toUpperCase());
            }

            if (preserveUserAgentHeader && !preserveHttpHeaders.contains(HTTP.USER_AGENT.toUpperCase())) {
                preserveHttpHeaders.add(HTTP.USER_AGENT.toUpperCase());
            }
        }

        public List<String> getPreserveHttpHeaders() {

            return preserveHttpHeaders;
        }

        public WorkerPool getWorkerPool() {

            return workerPool;
        }

        public ConfigurationContext getConfigurationContext() {

            return configurationContext;
        }
    }