content: /*
   * Copyright 1999-2018 Alibaba Group Holding Ltd.
   *
   * Licensed 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 com.alibaba.nacos.client.config.filter.impl;
  
  import java.util.List;
  
  import com.alibaba.nacos.api.config.filter.IConfigFilter;
  import com.alibaba.nacos.api.config.filter.IConfigFilterChain;
  import com.alibaba.nacos.api.config.filter.IConfigRequest;
  import com.alibaba.nacos.api.config.filter.IConfigResponse;
  import com.alibaba.nacos.api.exception.NacosException;
  
  import com.google.common.collect.Lists;
  
  /**
   * Config Filter Chain Management
   *
   * @author Nacos
   */
  public class ConfigFilterChainManager implements IConfigFilterChain {
  
      private List<IConfigFilter> filters = Lists.newArrayList();
  
      public synchronized ConfigFilterChainManager addFilter(IConfigFilter filter) {
          // 根据order大小顺序插入
          int i = 0;
          while (i < this.filters.size()) {
              IConfigFilter currentValue = this.filters.get(i);
              if (currentValue.getFilterName().equals(filter.getFilterName())) {
                  break;
              }
              if (filter.getOrder() >= currentValue.getOrder() && i < this.filters.size()) {
                  i++;
              } else {
                  this.filters.add(i, filter);
                  break;
              }
          }
  
          if (i == this.filters.size()) {
              this.filters.add(i, filter);
          }
          return this;
      }
  
      @Override
      public void doFilter(IConfigRequest request, IConfigResponse response) throws NacosException {
          new VirtualFilterChain(this.filters).doFilter(request, response);
      }
  
      private static class VirtualFilterChain implements IConfigFilterChain {
  
          private final List<? extends IConfigFilter> additionalFilters;
  
          private int currentPosition = 0;
  
          public VirtualFilterChain(List<? extends IConfigFilter> additionalFilters) {
              this.additionalFilters = additionalFilters;
          }
  
          @Override
          public void doFilter(final IConfigRequest request, final IConfigResponse response) throws NacosException {
              if (this.currentPosition != this.additionalFilters.size()) {
                  this.currentPosition++;
                  IConfigFilter nextFilter = this.additionalFilters.get(this.currentPosition - 1);
                  nextFilter.doFilter(request, response, this);
              }
          }
      }
  
  }
  