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.analysis.metrics;
  
  import java.util.ArrayList;
  import java.util.Comparator;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Set;
  import java.util.stream.Collectors;
  import lombok.EqualsAndHashCode;
  import lombok.ToString;
  import org.apache.skywalking.oap.server.core.Const;
  import org.apache.skywalking.oap.server.core.storage.type.StorageDataComplexObject;
  
  /**
   * DataTable includes a hashmap to store string key and long value. It enhanced the serialization capability.
   */
  @ToString
  @EqualsAndHashCode
  public class DataTable implements StorageDataComplexObject<DataTable> {
      private HashMap<String, Long> data;
  
      public DataTable() {
          data = new HashMap<>();
      }
  
      public DataTable(int initialCapacity) {
          data = new HashMap<>(initialCapacity);
      }
  
      public DataTable(String data) {
          this();
          toObject(data);
      }
  
      public Long get(String key) {
          return data.get(key);
      }
  
      public void put(String key, Long value) {
          data.put(key, value);
      }
  
      /**
       * Accumulate the value with existing value in the same given key.
       */
      public void valueAccumulation(String key, Long value) {
          Long element = data.get(key);
          if (element == null) {
              element = value;
          } else {
              element += value;
          }
          data.put(key, element);
      }
  
      /**
       * @return the sum of all values.
       */
      public long sumOfValues() {
          return data.values().stream().mapToLong(element -> element).sum();
      }
  
      public boolean keysEqual(DataTable that) {
          if (this.data.keySet().size() != that.data.keySet().size()) {
              return false;
          }
          return this.data.keySet().equals(that.data.keySet());
      }
  
      public List<String> sortedKeys(Comparator<String> keyComparator) {
          return data.keySet().stream().sorted(keyComparator).collect(Collectors.toList());
      }
  
      public List<Long> sortedValues(Comparator<String> keyComparator) {
          final List<String> collect = data.keySet().stream().sorted(keyComparator).collect(Collectors.toList());
          List<Long> values = new ArrayList<>(collect.size());
          collect.forEach(key -> values.add(data.get(key)));
          return values;
      }
  
      public Set<String> keys() {
          return data.keySet();
      }
  
      public boolean hasData() {
          return !data.isEmpty();
      }
  
      public boolean hasKey(String key) {
          return data.containsKey(key);
      }
  
      public int size() {
          return data.size();
      }
  
      @Override
      public String toStorageData() {
          StringBuilder builder = new StringBuilder();
  
          this.data.forEach((key, value) -> {
              if (builder.length() != 0) {
                  // For the first element.
                  builder.append(Const.ARRAY_SPLIT);
              }
              builder.append(key).append(Const.KEY_VALUE_SPLIT).append(value);
          });
          return builder.toString();
      }
  
      @Override
      public void toObject(String data) {
          String[] keyValues = data.split(Const.ARRAY_PARSER_SPLIT);
          for (String keyValue : keyValues) {
              final String[] keyValuePair = keyValue.split(Const.KEY_VALUE_SPLIT);
              if (keyValuePair.length == 2) {
                  this.data.put(keyValuePair[0], Long.parseLong(keyValuePair[1]));
              }
          }
      }
  
      @Override
      public void copyFrom(final DataTable source) {
          this.append(source);
      }
  
      public DataTable append(DataTable dataTable) {
          dataTable.data.forEach((key, value) -> {
              Long current = this.data.get(key);
              if (current == null) {
                  current = value;
              } else {
                  current += value;
              }
              this.data.put(key, current);
          });
          return this;
      }
  }
  