| #region License |
| |
| /* |
| * 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. |
| */ |
| |
| #endregion |
| |
| using System; |
| using System.Collections.Concurrent; |
| using System.Linq; |
| using System.Threading.Tasks; |
| using Gremlin.Net.Process; |
| |
| namespace Gremlin.Net.Driver |
| { |
| internal class ConnectionPool : IDisposable |
| { |
| private readonly ConnectionFactory _connectionFactory; |
| private readonly ConcurrentBag<Connection> _connections = new ConcurrentBag<Connection>(); |
| private readonly object _connectionsLock = new object(); |
| |
| public ConnectionPool(ConnectionFactory connectionFactory) |
| { |
| _connectionFactory = connectionFactory; |
| } |
| |
| public int NrConnections { get; private set; } |
| |
| public async Task<IConnection> GetAvailableConnectionAsync() |
| { |
| if (!TryGetConnectionFromPool(out var connection)) |
| connection = await CreateNewConnectionAsync().ConfigureAwait(false); |
| |
| return new ProxyConnection(connection, AddConnectionIfOpen); |
| } |
| |
| private bool TryGetConnectionFromPool(out Connection connection) |
| { |
| while (true) |
| { |
| connection = null; |
| lock (_connectionsLock) |
| { |
| if (_connections.IsEmpty) return false; |
| _connections.TryTake(out connection); |
| } |
| |
| if (connection.IsOpen) return true; |
| connection.Dispose(); |
| } |
| } |
| |
| private async Task<Connection> CreateNewConnectionAsync() |
| { |
| NrConnections++; |
| var newConnection = _connectionFactory.CreateConnection(); |
| await newConnection.ConnectAsync().ConfigureAwait(false); |
| return newConnection; |
| } |
| |
| private void AddConnectionIfOpen(Connection connection) |
| { |
| if (!connection.IsOpen) |
| { |
| ConsiderUnavailable(); |
| connection.Dispose(); |
| return; |
| } |
| AddConnection(connection); |
| } |
| |
| private void AddConnection(Connection connection) |
| { |
| lock (_connectionsLock) |
| { |
| _connections.Add(connection); |
| } |
| } |
| |
| private void ConsiderUnavailable() |
| { |
| CloseAndRemoveAllConnections(); |
| } |
| |
| private void CloseAndRemoveAllConnections() |
| { |
| lock (_connectionsLock) |
| { |
| TeardownAsync().WaitUnwrap(); |
| RemoveAllConnections(); |
| } |
| } |
| |
| private void RemoveAllConnections() |
| { |
| while (_connections.TryTake(out var connection)) |
| { |
| connection.Dispose(); |
| } |
| } |
| |
| private async Task TeardownAsync() |
| { |
| await Task.WhenAll(_connections.Select(c => c.CloseAsync())).ConfigureAwait(false); |
| } |
| |
| #region IDisposable Support |
| |
| private bool _disposed; |
| |
| public void Dispose() |
| { |
| Dispose(true); |
| GC.SuppressFinalize(this); |
| } |
| |
| protected virtual void Dispose(bool disposing) |
| { |
| if (!_disposed) |
| { |
| if (disposing) |
| CloseAndRemoveAllConnections(); |
| _disposed = true; |
| } |
| } |
| #endregion |
| } |
| } |