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.core.alarm.provider;
  
  import java.util.ArrayList;
  import java.util.List;
  import org.apache.skywalking.oap.server.core.alarm.MetaInAlarm;
  
  /**
   * This is a formatter especially for alarm message.
   * <p>
   * Format string in alarm-settings.yml, such as:
   * <p>
   * - Successful rate of endpoint {name} is lower than 75%
   */
  public class AlarmMessageFormatter {
      private List<String> formatSegments;
      private List<ValueFrom> valueFroms;
  
      public AlarmMessageFormatter(String format) {
          if (format == null) {
              format = "";
          }
          formatSegments = new ArrayList<>();
          this.valueFroms = new ArrayList<>();
          boolean match = false;
          int idx = 0;
          do {
              match = false;
              int start = format.indexOf("{", idx);
              if (start > -1) {
                  int end = format.indexOf("}", start);
                  if (end > -1) {
  
                      String name = format.substring(start + 1, end);
                      switch (name) {
                          case "id":
                              valueFroms.add(ValueFrom.ID);
                              break;
                          case "name":
                              valueFroms.add(ValueFrom.NAME);
                              break;
                          default:
                              throw new IllegalArgumentException("Var [" + name + "] in alarm message [" + format + "] is illegal");
                      }
                      formatSegments.add(format.substring(idx, start));
                      idx = end + 1;
                      match = true;
                  }
              }
  
              if (!match) {
                  formatSegments.add(format.substring(idx));
              }
          }
          while (match);
      }
  
      public String format(MetaInAlarm meta) {
          StringBuilder message = new StringBuilder();
          for (int i = 0; i < formatSegments.size(); i++) {
              message.append(formatSegments.get(i));
              if (i != formatSegments.size() - 1) {
                  switch (valueFroms.get(i)) {
                      case ID:
                          message.append(meta.getId0());
                          break;
                      case NAME:
                          message.append(meta.getName());
                  }
              }
          }
          return message.toString();
      }
  
      private enum ValueFrom {
          ID, NAME
      }
  }
  