content: /*
   * 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.cassandra.sidecar.adapters.base.db;
  
  import java.util.stream.Stream;
  import java.util.stream.StreamSupport;
  
  import com.datastax.driver.core.BoundStatement;
  import com.datastax.driver.core.ResultSet;
  import org.apache.cassandra.sidecar.adapters.base.db.schema.ConnectedClientsSchema;
  import org.apache.cassandra.sidecar.common.server.ICassandraAdapter;
  import org.apache.cassandra.sidecar.common.utils.Preconditions;
  import org.apache.cassandra.sidecar.db.LocalDatabaseAccessor;
  import org.apache.cassandra.sidecar.db.schema.TableSchemaFetcher;
  
  /**
   * DataAccessor implementation to read client connection stats from the table represented in {@link ConnectedClientsSchema}
   */
  public class ConnectedClientStatsDatabaseAccessor extends LocalDatabaseAccessor<ConnectedClientsSchema>
  {
      public ConnectedClientStatsDatabaseAccessor(TableSchemaFetcher tableSchemaFetcher, ICassandraAdapter cassandraAdapter)
      {
          super(tableSchemaFetcher.tableSchema(ConnectedClientsSchema.class), cassandraAdapter);
      }
  
      /**
       * Query for a summary of the client connection stats
       * @return {@link ConnectedClientStatsSummary} with total connections and counts grouped by user
       */
      public ConnectedClientStatsSummary summary()
      {
          Preconditions.checkState(tableSchema.isInitialized(), () -> tableSchema.getClass().getSimpleName() + " is not initialized yet");
          BoundStatement statement = tableSchema.connectionsByUser().bind();
          ResultSet resultSet = execute(statement);
          return ConnectedClientStatsSummary.from(resultSet);
      }
  
      /**
       * Query for all the client connection stats with an entry per connection
       * @return {@link ConnectedClientStats} for each connection
       */
      public Stream<ConnectedClientStats> stats()
      {
          Preconditions.checkState(tableSchema.isInitialized(), () -> tableSchema.getClass().getSimpleName() + " is not initialized yet");
          BoundStatement statement = tableSchema.stats().bind();
          ResultSet resultSet = execute(statement);
          return StreamSupport.stream(resultSet.spliterator(), false)
                              .map(ConnectedClientStats::from);
      }
  }
  