/trunk/SSATool.UI.ViewModel/DataServiceCollection.cs

#region Header

// ------------------------ Licence / Copyright ------------------------

// 

// Simple Service Administration Tool for WinNT based systems.

// Copyright © 2010 - Silvan Gehrig

// 

// This library is free software; you can redistribute it and/or

// modify it under the terms of the GNU Lesser General Public

// License as published by the Free Software Foundation; either

// version 2.1 of the License, or (at your option) any later version.

// 

// This library is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

// Lesser General Public License for more details.

// 

// You should have received a copy of the GNU Lesser General Public

// License along with this library; if not, write to the Free Software

// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

// 

// Author:

//  Silvan Gehrig

//

// ---------------------------------------------------------------------

#endregion



#region Usings



using System;

using System.Collections.ObjectModel;

using System.Collections.Specialized;

using SSATool.BL.DM;

using SSATool.Common.Util;

using System.ComponentModel;



#endregion



namespace SSATool.UI.ViewModel

{

    /// <summary>

    /// Represents a collection of service instances.

    /// </summary>

    public class DataServiceCollection : ObservableCollection<DataService>

    {

        #region Declarations

        //--------------------------------------------------------------------

        // Declarations

        //--------------------------------------------------------------------



        private readonly ServiceCollection _domainCollection;



        private bool _eventAdded = false;

        private bool _innerEventsEnabled = true;

        private NotifyCollectionChangedEventHandler _onCollectionChanged;



        #endregion



        #region Properties

        //--------------------------------------------------------------------

        // Properties

        //--------------------------------------------------------------------



        /// <summary>

        /// Gets the service with the given name.

        /// </summary>

        /// <param name="serviceName">Name of the service to retrieve.</param>

        /// <returns>Returns the retrieved service or fires an exception if it could not be found.</returns>

        public DataService this[string serviceName]

        {

            get { return new DataService(this, _domainCollection[serviceName]); }

        }



        #endregion



        #region Constructors / Destructor

        //--------------------------------------------------------------------

        // Constructors / Destructor

        //--------------------------------------------------------------------



        /// <summary>

        /// Initializes a new instance of the <see cref="DataServiceCollection"/> class.

        /// </summary>

        /// <param name="domainCollection">Specifies the parent domain collection instance.</param>

        public DataServiceCollection(ServiceCollection domainCollection)

        {

            PreCondition.AssertNotNull(domainCollection, "domainCollection");



            _domainCollection = domainCollection;

        }



        #endregion



        #region Methods

        //--------------------------------------------------------------------

        // Methods

        //--------------------------------------------------------------------



        /// <summary>

        /// Determines whether the current collection contains the specified item.

        /// </summary>

        /// <param name="serviceName">The name of the service to check.</param>

        /// <returns>

        /// 	<c>true</c> if the current collection contains the specified item; otherwise, <c>false</c>.

        /// </returns>

        public bool Contains(string serviceName)

        {

            PreCondition.AssertNotNull(serviceName, "serviceName");

            return _domainCollection.Contains(serviceName);

        }



        /// <summary>

        /// Refreshes the data with the underlying data source.

        /// </summary>

        public void Reset()

        {

            CallWithoutInnerEvents(() => _domainCollection.Reset());

            Clear();



            foreach (Service service in _domainCollection)

            {

                Items.Add(new DataService(this, service));

            }

            OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));

        }



        /// <summary>

        /// Fires the ChildPropertyChanged event.

        /// </summary>

        /// <param name="sender">Specifies the sender service instance.</param>

        /// <param name="args">Event args to pass to the receivers.</param>

        internal void FireChildChanged(DataService sender, PropertyChangedEventArgs args)

        {

            if (ChildChanged != null)

                ChildChanged(sender, args);

        }



        private void CallWithoutInnerEvents(Action toExecute)

        {

            try

            {

                _innerEventsEnabled = false;

                toExecute();

            }

            finally

            {

                _innerEventsEnabled = true;

            }

        }



        private void EnsureCollectionChangedEventAdded()

        {

            if (!_eventAdded)

            {

                _domainCollection.CollectionChanged += OnDomainCollectionCollectionChanged;

                _eventAdded = true;

            }

        }



        private void EnsureCollectionChangedEventRemoved()

        {

            if (_onCollectionChanged != null && _eventAdded)

            {

                _domainCollection.CollectionChanged -= OnDomainCollectionCollectionChanged;

                _eventAdded = false;

            }

        }



        #endregion



        #region Events

        //--------------------------------------------------------------------

        // Events

        //--------------------------------------------------------------------



        /// <summary>

        /// Occurs when a child item mutated.

        /// </summary>

        public event PropertyChangedEventHandler ChildChanged;



        /// <summary>

        /// Occurs when an item is added, removed, changed, moved, or the entire list is refreshed.

        /// </summary>

        public event NotifyCollectionChangedEventHandler Changed

        {

            add

            {

                _onCollectionChanged += value;

                EnsureCollectionChangedEventAdded();

            }

            remove

            {

                _onCollectionChanged -= value;

                EnsureCollectionChangedEventRemoved();

            }

        }



        /// <summary>

        /// Occurs when an item is added, removed, changed, moved, or the entire list is refreshed.

        /// </summary>

        public override event NotifyCollectionChangedEventHandler CollectionChanged

        {

            add

            {

                _onCollectionChanged += value;

                EnsureCollectionChangedEventAdded();

            }

            remove

            {

                _onCollectionChanged -= value;

                EnsureCollectionChangedEventRemoved();

            }

        }



        private void OnDomainCollectionCollectionChanged(object sender, ServiceCollectionChangedEventArgs e)

        {

            if (!_innerEventsEnabled)

                return;



            switch (e.Action)

            {

                case ServiceCollectionChangedAction.Add:

                    Add(new DataService(this, e.ChangedItem));

                    break;

                case ServiceCollectionChangedAction.Remove:

                    Remove(new DataService(this, e.ChangedItem));

                    break;

                case ServiceCollectionChangedAction.Reset:

                    Reset();

                    break;

                default:

                    throw new ArgumentOutOfRangeException();

            }

        }



        #endregion

    }

}