package com.github.davidmoten.rx.jdbc;
   
   import java.sql.Connection;
   import java.sql.SQLException;
   import java.util.concurrent.atomic.AtomicBoolean;
   
   import com.github.davidmoten.rx.jdbc.exceptions.SQLRuntimeException;
   
   /**
   * Provides a singleton {@link Connection} sourced from a
   * {@link ConnectionProvider} that has autoCommit set to false.
   */
  final class ConnectionProviderSingletonManualCommit implements ConnectionProvider {
  
      /**
       * Singleton connection.
       */
      private Connection con;
  
      /**
       * Ensures thread-safe setting of con
       */
      private AtomicBoolean connectionSet = new AtomicBoolean(false);
  
      /**
       * Provides the singleton connection.
       */
      private final ConnectionProvider cp;
  
      /**
       * Constructor.
       * 
       * @param cp
       *            connection provider.
       */
      ConnectionProviderSingletonManualCommit(ConnectionProvider cp) {
          this.cp = cp;
      }
  
      @Override
      public Connection get() {
          if (connectionSet.compareAndSet(false, true)) {
              con = cp.get();
              try {
                  con.setAutoCommit(false);
              } catch (SQLException e) {
                  throw new SQLRuntimeException(e);
              }
          }
          return con;
      }
  
      @Override
      public void close() {
          cp.close();
      }
  
  }