content: /*
   * Copyright 1999-2020 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.common.labels.impl;
  
  import com.alibaba.nacos.common.labels.LabelsCollector;
  import com.alibaba.nacos.common.labels.LabelsCollectorManager;
  import com.alibaba.nacos.common.utils.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Properties;
  import java.util.ServiceLoader;
  
  /**
   * DefaultLabelsCollectorManager.
   *
   * @author rong
   */
  public class DefaultLabelsCollectorManager implements LabelsCollectorManager {
      
      private static final Logger LOGGER = LoggerFactory.getLogger("com.alibaba.nacos.common.labels");
      
      private ArrayList<LabelsCollector> labelsCollectorsList = new ArrayList<>();
      
      public DefaultLabelsCollectorManager() {
          labelsCollectorsList = loadLabelsCollectors();
      }
      
      @Override
      public Map<String, String> getLabels(Properties properties) {
          LOGGER.info("DefaultLabelsCollectorManager get labels.....");
          Map<String, String> labels = getLabels(labelsCollectorsList, properties);
          LOGGER.info("DefaultLabelsCollectorManager get labels finished,labels :{}", labels);
          return labels;
      }
      
      Map<String, String> getLabels(ArrayList<LabelsCollector> labelsCollectorsList, Properties properties) {
          
          if (properties == null) {
              properties = new Properties();
          }
          Map<String, String> labels = new HashMap<>(8);
          for (LabelsCollector labelsCollector : labelsCollectorsList) {
              
              LOGGER.info("Process LabelsCollector with [name:{}]", labelsCollector.getName());
              for (Map.Entry<String, String> entry : labelsCollector.collectLabels(properties).entrySet()) {
                  if (!checkValidLabel(entry.getKey(), entry.getValue())) {
                      LOGGER.info(" ignore invalid label with [key:{}, value:{}] of collector [name:{}]", entry.getKey(),
                              entry.getValue(), labelsCollector.getName());
                      continue;
                  }
                  if (innerAddLabel(labels, entry.getKey(), entry.getValue())) {
                      LOGGER.info("pick label with [key:{}, value:{}] of collector [name:{}]", entry.getKey(),
                              entry.getValue(), labelsCollector.getName());
                  } else {
                      LOGGER.info(" ignore label with [key:{}, value:{}] of collector [name:{}],"
                                      + "already existed in LabelsCollectorManager with previous [value:{}]，", entry.getKey(),
                              entry.getValue(), labelsCollector.getName(), labels.get(entry.getKey()));
                  }
              }
          }
          return labels;
      }
      
      private boolean checkValidLabel(String key, String value) {
          return isValid(key) && isValid(value);
      }
      
      private static boolean isValid(String param) {
          if (StringUtils.isBlank(param)) {
              return false;
          }
          int length = param.length();
          if (length > maxLength) {
              return false;
          }
          for (int i = 0; i < length; i++) {
              char ch = param.charAt(i);
              if (!Character.isLetterOrDigit(ch) && !isValidChar(ch)) {
                  return false;
              }
          }
          return true;
      }
      
      private static char[] validChars = new char[] {'_', '-', '.'};
      
      private static int maxLength = 128;
      
      private static boolean isValidChar(char ch) {
          for (char c : validChars) {
              if (c == ch) {
                  return true;
              }
          }
          return false;
      }
      
      private ArrayList<LabelsCollector> loadLabelsCollectors() {
          ServiceLoader<LabelsCollector> labelsCollectors = ServiceLoader.load(LabelsCollector.class);
          ArrayList<LabelsCollector> labelsCollectorsList = new ArrayList<>();
          for (LabelsCollector labelsCollector : labelsCollectors) {
              labelsCollectorsList.add(labelsCollector);
          }
          labelsCollectorsList.sort((o1, o2) -> o2.getOrder() - o1.getOrder());
          return labelsCollectorsList;
      }
      
      private boolean innerAddLabel(Map<String, String> labels, String key, String value) {
          return null == labels.putIfAbsent(key, value);
      }
  }
  