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.query.promql.entity;
  
  import com.fasterxml.jackson.annotation.JsonValue;
  import com.fasterxml.jackson.databind.annotation.JsonSerialize;
  import java.util.Arrays;
  import java.util.HashMap;
  import java.util.Map;
  
  @JsonSerialize()
  public enum LabelName {
      NAME("__name__"),
      LAYER("layer"),
      SCOPE("scope"),
      SERVICE("service"),
      SERVICE_INSTANCE("service_instance"),
      ENDPOINT("endpoint"),
      //For labeled value query
      LABELS("labels"),
      RELABELS("relabels"),
      //For labeled value
      LABEL("label"),
      //For tonN and record
      PARENT_SERVICE("parent_service"),
      TOP_N("top_n"),
      ORDER("order"),
      RECORD("record"),
      //For endpoint_traffic
      LIMIT("limit"),
      KEYWORD("keyword");
  
      final String label;
  
      private static final Map<String, LabelName> DICTIONARY = new HashMap<>();
  
      static {
          Arrays.stream(LabelName.values()).forEach(l -> {
              DICTIONARY.put(l.label, l);
          });
      }
  
      LabelName(final String label) {
          this.label = label;
      }
  
      public static LabelName labelOf(String label) {
          LabelName labelName = DICTIONARY.get(label);
          if (labelName == null) {
              throw new IllegalArgumentException("Unknown Label Name: " + label);
          }
          return labelName;
      }
  
      @JsonValue
      public String getLabel() {
          return this.label;
      }
  
      @Override
      public String toString() {
          return label;
      }
  }
  