xenadmin/XenModel/Actions/MultipleActionLauncher.cs

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using System.Collections.Generic;
using System.Collections.ObjectModel;
using XenAdmin.Network;

namespace XenAdmin.Actions
{
    /// <summary>
    /// A class for running <see cref="AsyncAction"/>s such that they are synchronous per connection but asynchronous across connections.
    /// </summary>
    public class MultipleActionLauncher
    {
        private readonly ReadOnlyCollection<AsyncAction> _actions;
        private readonly string _title;
        private readonly string _startDescription;
        private readonly string _endDescription;
        private readonly bool _runActionInParallel;

        public MultipleActionLauncher(IEnumerable<AsyncAction> actions, string title, string startDescription, string endDescription, bool runActionInParallel)
        {
            Util.ThrowIfParameterNull(actions, "actions");

            _actions = new ReadOnlyCollection<AsyncAction>(new List<AsyncAction>(actions));
            _title = title;
            _startDescription = startDescription;
            _endDescription = endDescription;
            _runActionInParallel = runActionInParallel;
        }

        public void Run()
        {
            Dictionary<IXenConnection, List<AsyncAction>> actionsByConnection = new Dictionary<IXenConnection, List<AsyncAction>>();
            List<AsyncAction> actionsWithNoConnection = new List<AsyncAction>();

            foreach (AsyncAction action in _actions)
            {
                if (action.Connection != null)
                {
                    if (action.Connection.IsConnected)
                    {
                        if (!actionsByConnection.ContainsKey(action.Connection))
                        {
                            actionsByConnection.Add(action.Connection, new List<AsyncAction>());
                        }

                        actionsByConnection[action.Connection].Add(action);
                    }
                }
                else
                {
                    actionsWithNoConnection.Add(action);
                }
            }

            foreach (IXenConnection connection in actionsByConnection.Keys)
            {
                if (actionsByConnection[connection].Count == 1)
                {
                    actionsByConnection[connection][0].RunAsync();
                }
                else
                {
                    if (_runActionInParallel)
                        new ParallelAction(_title, _startDescription, _endDescription, actionsByConnection[connection], connection).RunAsync();
                    else
                        new MultipleAction(connection, _title, _startDescription, _endDescription, actionsByConnection[connection]).RunAsync();
                }
            }

            if (actionsWithNoConnection.Count == 1)
            {
                actionsWithNoConnection[0].RunAsync();
            }
            else if (actionsWithNoConnection.Count > 1)
            {
                if (_runActionInParallel)
                    new ParallelAction(_title, _startDescription, _endDescription, actionsWithNoConnection).RunAsync();
                else
                    new MultipleAction(null, _title, _startDescription, _endDescription, actionsWithNoConnection).RunAsync();
            }
        }
    }
}