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.db.virtual;
  
  import java.util.EnumSet;
  import java.util.Map;
  import java.util.function.Supplier;
  
  import com.google.common.annotations.VisibleForTesting;
  import org.apache.cassandra.db.marshal.InetAddressType;
  import org.apache.cassandra.db.marshal.Int32Type;
  import org.apache.cassandra.db.marshal.UTF8Type;
  import org.apache.cassandra.dht.LocalPartitioner;
  import org.apache.cassandra.gms.ApplicationState;
  import org.apache.cassandra.gms.EndpointState;
  import org.apache.cassandra.gms.Gossiper;
  import org.apache.cassandra.gms.VersionedValue;
  import org.apache.cassandra.locator.InetAddressAndPort;
  import org.apache.cassandra.schema.TableMetadata;
  
  import static org.apache.cassandra.gms.ApplicationState.TOKENS;
  import static org.apache.cassandra.utils.LocalizeString.toLowerCaseLocalized;
  
  /**
   * A {@link VirtualTable} that return the Gossip information in tabular format.
   */
  final class GossipInfoTable extends AbstractVirtualTable
  {
      static final String TABLE_NAME = "gossip_info";
      static final String TABLE_COMMENT = "lists the gossip information for the cluster";
  
      static final String ADDRESS = "address";
      static final String PORT = "port";
      static final String HOSTNAME = "hostname";
      static final String GENERATION = "generation";
      static final String HEARTBEAT = "heartbeat";
  
      static final ApplicationState[] STATES_FOR_VERSIONS = ApplicationState.values();
      static final ApplicationState[] STATES_FOR_VALUES;
  
      static
      {
          EnumSet<ApplicationState> applicationStates = EnumSet.allOf(ApplicationState.class);
          // do not add a column for the ApplicationState.TOKENS value
          applicationStates.remove(TOKENS);
          STATES_FOR_VALUES = applicationStates.toArray(new ApplicationState[0]);
      }
  
      private final Supplier<Map<InetAddressAndPort, EndpointState>> endpointStateMapSupplier;
  
      /**
       * Construct a new {@link GossipInfoTable} for the given {@code keyspace}.
       *
       * @param keyspace the name of the keyspace
       */
      GossipInfoTable(String keyspace)
      {
          this(keyspace, () -> Gossiper.instance.endpointStateMap);
      }
  
      @VisibleForTesting
      GossipInfoTable(String keyspace, Supplier<Map<InetAddressAndPort, EndpointState>> endpointStateMapSupplier)
      {
          super(buildTableMetadata(keyspace));
          this.endpointStateMapSupplier = endpointStateMapSupplier;
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public DataSet data()
      {
          SimpleDataSet result = new SimpleDataSet(metadata());
          for (Map.Entry<InetAddressAndPort, EndpointState> entry : endpointStateMapSupplier.get().entrySet())
          {
              InetAddressAndPort endpoint = entry.getKey();
              // we are making a copy of endpoint state as a value of an entry of the returned map
              // might be updated on the fly by LoadBroadcaster, and we want to be sure that
              // the returned data are capturing a particular point in time
              EndpointState localState = new EndpointState(entry.getValue());
  
              SimpleDataSet dataSet = result.row(endpoint.getAddress(), endpoint.getPort())
                                            .column(HOSTNAME, endpoint.getHostName())
                                            .column(GENERATION, getGeneration(localState))
                                            .column(HEARTBEAT, getHeartBeat(localState));
  
              for (ApplicationState state : STATES_FOR_VALUES)
                  dataSet.column(toLowerCaseLocalized(state.name()), getValue(localState, state));
  
              for (ApplicationState state : STATES_FOR_VERSIONS)
                  dataSet.column(toLowerCaseLocalized(state.name()) + "_version", getVersion(localState, state));
          }
          return result;
      }
  
      /**
       * Return the heartbeat generation of a given {@link EndpointState} or null if {@code localState} is null.
       *
       * @param localState a nullable endpoint state
       * @return the heartbeat generation if available, null otherwise
       */
      private Integer getGeneration(EndpointState localState)
      {
          return localState == null ? null : localState.getHeartBeatState().getGeneration();
      }
  
      /**
       * Return the heartbeat version of a given {@link EndpointState} or null if {@code localState} is null.
       *
       * @param localState a nullable endpoint state
       * @return the heartbeat version if available, null otherwise
       */
      private Integer getHeartBeat(EndpointState localState)
      {
          return localState == null ? null : localState.getHeartBeatState().getHeartBeatVersion();
      }
  
      /**
       * Returns the value from the {@link VersionedValue} of a given {@link ApplicationState key}, or null
       * if {@code localState} is null or the {@link VersionedValue} does not exist in the {@link ApplicationState}.
       *
       * @param localState a nullable endpoint state
       * @param key        the key to the application state
       * @return the value, or null if not available
       */
      private String getValue(EndpointState localState, ApplicationState key)
      {
          VersionedValue value;
          return localState == null || (value = localState.getApplicationState(key)) == null ? null : value.value;
      }
  
      /**
       * Returns the version from the {@link VersionedValue} of a given {@link ApplicationState key}, or null
       * if {@code localState} is null or the {@link VersionedValue} does not exist in the {@link ApplicationState}.
       *
       * @param localState a nullable endpoint state
       * @param key        the key to the application state
       * @return the version, or null if not available
       */
      private Integer getVersion(EndpointState localState, ApplicationState key)
      {
          VersionedValue value;
          return localState == null || (value = localState.getApplicationState(key)) == null ? null : value.version;
      }
  
      /**
       * Builds the {@link TableMetadata} to be provided to the superclass
       *
       * @param keyspace the name of the keyspace
       * @return the TableMetadata class
       */
      private static TableMetadata buildTableMetadata(String keyspace)
      {
          TableMetadata.Builder builder = TableMetadata.builder(keyspace, TABLE_NAME)
                                                       .comment(TABLE_COMMENT)
                                                       .kind(TableMetadata.Kind.VIRTUAL)
                                                       .partitioner(new LocalPartitioner(InetAddressType.instance))
                                                       .addPartitionKeyColumn(ADDRESS, InetAddressType.instance)
                                                       .addClusteringColumn(PORT, Int32Type.instance)
                                                       .addRegularColumn(HOSTNAME, UTF8Type.instance)
                                                       .addRegularColumn(GENERATION, Int32Type.instance)
                                                       .addRegularColumn(HEARTBEAT, Int32Type.instance);
  
          for (ApplicationState state : STATES_FOR_VALUES)
              builder.addRegularColumn(toLowerCaseLocalized(state.name()), UTF8Type.instance);
  
          for (ApplicationState state : STATES_FOR_VERSIONS)
              builder.addRegularColumn(toLowerCaseLocalized(state.name()) + "_version", Int32Type.instance);
  
          return builder.build();
      }
  }
  