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.apex.malhar.contrib.cassandra;
  
  import javax.validation.constraints.NotNull;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.apache.apex.malhar.lib.db.Connectable;
  
  import com.datastax.driver.core.Cluster;
  import com.datastax.driver.core.ProtocolVersion;
  import com.datastax.driver.core.Session;
  import com.datastax.driver.core.exceptions.DriverException;
  import com.datatorrent.netlet.util.DTThrowable;
  
  /**
   * A {@link Connectable} that uses cassandra to connect to stores and implements Connectable interface.
   * <p>
   * @displayName Cassandra Store
   * @category Output
   * @tags cassandra
   * @since 1.0.2
   */
  public class CassandraStore implements Connectable
  {
    protected static final Logger logger = LoggerFactory.getLogger(CassandraStore.class);
    private String userName;
    private String password;
    @NotNull
    private String node;
    protected transient Cluster cluster = null;
    protected transient Session session = null;
    private String protocolVersion;
  
    @NotNull
    protected String keyspace;
  
    /*
     * The Cassandra keyspace is a namespace that defines how data is replicated on nodes.
     * Typically, a cluster has one keyspace per application. Replication is controlled on a per-keyspace basis, so data that has different replication requirements typically resides in different keyspaces.
     * Keyspaces are not designed to be used as a significant map layer within the data model. Keyspaces are designed to control data replication for a set of tables.
     */
    public String getKeyspace()
    {
      return keyspace;
    }
  
    /**
     * Sets the keyspace.
     *
     * @param keyspace keyspace.
     */
    public void setKeyspace(String keyspace)
    {
      this.keyspace = keyspace;
    }
  
    /**
     * Sets the user name.
     *
     * @param userName user name.
     */
    public void setUserName(String userName)
    {
      this.userName = userName;
    }
  
    /**
     * Sets the password.
     *
     * @param password password
     */
    public void setPassword(String password)
    {
      this.password = password;
    }
  
    public String getProtocolVersion()
    {
      return protocolVersion;
    }
  
    /**
     * Sets the protocolVersion of Cassandra
     * @param protocolVersion as V1, V2, V3 etc
     */
    public void setProtocolVersion(String protocolVersion)
    {
      this.protocolVersion = protocolVersion;
    }
  
    @NotNull
    public String getNode()
    {
      return node;
    }
  
    /**
     * Sets the node.
     *
     * @param node node
     */
    public void setNode(@NotNull String node)
    {
      this.node = node;
    }
  
    public Cluster getCluster()
    {
      return cluster;
    }
  
    public Session getSession()
    {
      return session;
    }
  
    /**
     * Creates a cluster object.
     */
    public void buildCluster()
    {
      try {
        if (protocolVersion != null && protocolVersion.length() != 0) {
          ProtocolVersion version = getCassandraProtocolVersion();
          cluster = Cluster.builder().addContactPoint(node).withCredentials(userName, password).withProtocolVersion(version).build();
        } else {
          cluster = Cluster.builder().addContactPoint(node).withCredentials(userName, password).build();
        }
      } catch (DriverException ex) {
        throw new RuntimeException("closing database resource", ex);
      } catch (Throwable t) {
        DTThrowable.rethrow(t);
      }
    }
  
    private ProtocolVersion getCassandraProtocolVersion()
    {
      switch (protocolVersion.toUpperCase()) {
        case "V1":
          return ProtocolVersion.V1;
        case "V2":
          return ProtocolVersion.V2;
        case "V3":
          return ProtocolVersion.V3;
        default:
          throw new RuntimeException("Unsupported Cassandra Protocol Version.");
      }
    }
  
    /**
     * Create connection with database.
     */
    @Override
    public void connect()
    {
      try {
        if (cluster == null) {
          buildCluster();
        }
        session = cluster.connect();
        logger.debug("Cassandra connection Success");
      } catch (DriverException ex) {
        throw new RuntimeException("closing database resource", ex);
      } catch (Throwable t) {
        DTThrowable.rethrow(t);
      }
    }
  
    /**
     * Close connection.
     */
    @Override
    public void disconnect()
    {
      try {
        session.close();
        cluster.close();
      } catch (DriverException ex) {
        throw new RuntimeException("closing database resource", ex);
      } catch (Throwable t) {
        DTThrowable.rethrow(t);
      }
    }
  
    @Override
    public boolean isConnected()
    {
      try {
        return !session.isClosed();
      } catch (DriverException ex) {
        throw new RuntimeException("closing database resource", ex);
      }
    }
  }
  