code: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF 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.skywalking.oap.server.analyzer.provider.trace.sampling;
  
  import org.apache.skywalking.oap.server.library.util.StringUtil;
  import org.yaml.snakeyaml.LoaderOptions;
  import org.yaml.snakeyaml.Yaml;
  import org.yaml.snakeyaml.constructor.SafeConstructor;
  
  import java.io.InputStream;
  import java.io.Reader;
  import java.util.List;
  import java.util.Map;
  import java.util.Objects;
  
  /**
   * SamplePolicySettingsReader parses the given `trace-sampling-policy-settings.yml` config file, to the target {@link
   * SamplingPolicySettings}.
   */
  public class SamplingPolicySettingsReader {
      private Map<String, ?> yamlData;
  
      public SamplingPolicySettingsReader(InputStream inputStream) {
          Yaml yaml = new Yaml(new SafeConstructor(new LoaderOptions()));
          yamlData = yaml.load(inputStream);
      }
  
      public SamplingPolicySettingsReader(Reader io) {
          Yaml yaml = new Yaml(new SafeConstructor(new LoaderOptions()));
          yamlData = yaml.load(io);
      }
  
      /**
       * Read policy config file to {@link SamplingPolicySettings}
       */
      public SamplingPolicySettings readSettings() {
          SamplingPolicySettings samplingPolicySettings = new SamplingPolicySettings();
          if (Objects.nonNull(yamlData)) {
              readDefaultSamplingPolicy(samplingPolicySettings);
              readServicesSamplingPolicy(samplingPolicySettings);
          }
          return samplingPolicySettings;
      }
  
      private void readDefaultSamplingPolicy(SamplingPolicySettings samplingPolicySettings) {
          Map<String, Object> objectMap = (Map<String, Object>) yamlData.get("default");
          if (objectMap == null) {
              return;
          }
          if (objectMap.get("rate") != null) {
              samplingPolicySettings.getDefaultPolicy().setRate((Integer) objectMap.get("rate"));
          }
          if (objectMap.get("duration") != null) {
              samplingPolicySettings.getDefaultPolicy().setDuration((Integer) objectMap.get("duration"));
          }
      }
  
      private void readServicesSamplingPolicy(SamplingPolicySettings samplingPolicySettings) {
          Map<String, Object> objectMap = (Map<String, Object>) yamlData;
          Object servicesObject = objectMap.get("services");
          if (servicesObject != null) {
              List<Map<String, Object>> serviceList = (List<Map<String, Object>>) servicesObject;
              serviceList.forEach(service -> {
                  String name = (String) service.get("name");
                  if (StringUtil.isBlank(name)) {
                      return;
                  }
                  SamplingPolicy samplingPolicy = new SamplingPolicy();
                  samplingPolicy.setRate(service.get("rate") == null ? null : (Integer) service.get("rate"));
                  samplingPolicy.setDuration(service.get("duration") == null ? null : (Integer) service.get("duration"));
                  samplingPolicySettings.add(name, samplingPolicy);
              });
          }
      }
  }
  