NavigatorBase.cs :  » Web-Frameworks » Ingenious-MVC » Ingenious » Mvc » Navigators » C# / CSharp Open Source

#region License

/**
 * Ingenious MVC : An MVC framework for .NET 2.0
 * Copyright (C) 2006, JDP Group
 * 
 * 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
 * 
 * Authors: - Kent Boogaart (kentcb@internode.on.net)
 */

#endregion

using System;
using Ingenious.Mvc;
using Ingenious.Mvc.Configuration;
using Ingenious.Mvc.Util;

namespace Ingenious.Mvc.Navigators{
  /// <include file='NavigatorBase.doc.xml' path='/doc/member[@name="T:NavigatorBase"]/*'/>
  [Serializable]
  public abstract class NavigatorBase : INavigator
  {
    private readonly Id<INavigator> _id;
    private readonly Task _task;
    private readonly Id<IView> _startingViewId;
    private readonly IViewManager _viewManager;
    private Id<IView> _lastNavigateTo;

    /// <include file='NavigatorBase.doc.xml' path='/doc/member[@name="P:Id"]/*'/>
    public Id<INavigator> Id
    {
      get
      {
        return _id;
      }
    }

    /// <include file='NavigatorBase.doc.xml' path='/doc/member[@name="P:Task"]/*'/>
    public Task Task
    {
      get
      {
        return _task;
      }
    }

    /// <include file='NavigatorBase.doc.xml' path='/doc/member[@name="P:StartingViewId"]/*'/>
    public Id<IView> StartingViewId
    {
      get
      {
        return _startingViewId;
      }
    }

    /// <include file='NavigatorBase.doc.xml' path='/doc/member[@name="P:LastNavigateTo"]/*'/>
    public Id<IView> LastNavigateTo
    {
      get
      {
        return _lastNavigateTo;
      }
    }

    /// <include file='NavigatorBase.doc.xml' path='/doc/member[@name="P:ViewManager"]/*'/>
    protected IViewManager ViewManager
    {
      get
      {
        return _viewManager;
      }
    }

    /// <include file='NavigatorBase.doc.xml' path='/doc/member[@name="M:.ctor(Ingenious.Mvc.Id`1,Ingenious.Mvc.Task,Ingenious.Mvc.Id`1,Ingenious.Mvc.IViewManager)"]/*'/>
    protected NavigatorBase(Id<INavigator> id, Task task, Id<IView> startingViewId, IViewManager viewManager)
    {
      ArgumentHelper.AssertNotEmpty(id, "id");
      ArgumentHelper.AssertNotNull(task, "task");
      ArgumentHelper.AssertNotEmpty(startingViewId, "startingViewId");
      ArgumentHelper.AssertNotNull(viewManager, "viewManager");
      _id = id;
      _task = task;
      _startingViewId = startingViewId;
      _viewManager = viewManager;
    }

    /// <include file='NavigatorBase.doc.xml' path='/doc/member[@name="M:Initialize()"]/*'/>
    public virtual void Initialize()
    {
    }

    /// <include file='NavigatorBase.doc.xml' path='/doc/member[@name="M:CanNavigateTo(Ingenious.Mvc.Id`1)"]/*'/>
    public virtual bool CanNavigateTo(Id<IView> viewId)
    {
      ArgumentHelper.AssertNotEmpty(viewId, "viewId");
      return AssertNavigateToValid(ref viewId, false);;
    }

    /// <include file='NavigatorBase.doc.xml' path='/doc/member[@name="M:NavigateTo(Ingenious.Mvc.Id`1)"]/*'/>
    public virtual IView NavigateTo(Id<IView> viewId)
    {
      return NavigateTo(viewId, null);
    }

    /// <include file='NavigatorBase.doc.xml' path='/doc/member[@name="M:NavigateTo(Ingenious.Mvc.Id`1,System.Object)"]/*'/>
    public virtual IView NavigateTo(Id<IView> viewId, object viewData)
    {
      ArgumentHelper.AssertNotEmpty(viewId, "viewId");
      //ask the base class to assert the navigation attempt
      Id<IView> targetViewId = viewId;
      AssertNavigateToValid(ref targetViewId, true);

      if (targetViewId == Id<IView>.Empty)
      {
        targetViewId = viewId;
      }

      //allow subclasses to perform additional processing
      BeforeNavigateTo(targetViewId, viewData);
      //if we get here, the navigation is valid so do it
      return DoNavigateTo(targetViewId, viewData);
    }

    /// <include file='NavigatorBase.doc.xml' path='/doc/member[@name="M:BeforeNavigateTo(Ingenious.Mvc.Id`1,System.Object)"]/*'/>
    protected virtual void BeforeNavigateTo(Id<IView> viewId, object viewData)
    {
    }

    /// <include file='NavigatorBase.doc.xml' path='/doc/member[@name="M:AssertNavigateToValid(Ingenious.Mvc.Id`1&amp;,System.Boolean)"]/*'/>
    protected abstract bool AssertNavigateToValid(ref Id<IView> viewId, bool throwOnError);

    private IView DoNavigateTo(Id<IView> targetViewId, object viewData)
    {
      ExceptionHelper.ThrowIf(Task.Manager.ConfigurationInfo == null, "DoNavigateTo.noConfiguration", new object[] {ViewManager.ActiveView, targetViewId}, Id, targetViewId);
      ArgumentHelper.AssertNotEmpty(targetViewId, "targetViewId");
      ViewInfo viewInfo = Task.Manager.ConfigurationInfo.ViewInfos[targetViewId];
      ExceptionHelper.ThrowIf(viewInfo == null, "DoNavigateTo.viewNotFound", new object[] {ViewManager.ActiveView, targetViewId}, Id, targetViewId);

      //if we get here then the navigation is legal
      IController controller = Task.Manager.GetControllerForTask(Task, viewInfo.ControllerInfo, Task.Manager.ConfigurationInfo.ControllerFactory);
      //remember this in case we need to roll back
      Id<IView> lastNavigateToCopy = _lastNavigateTo;
      IView view = null;

      try
      {
        //store the last navigation before we activate the view because the view might display modally and block us
        _lastNavigateTo = targetViewId;
        //ask the view manager to activate the view
        view = ViewManager.Activate(Task, targetViewId, viewData);
      }
      catch (Exception)
      {
        //revert the last navigation because it failed
        _lastNavigateTo = lastNavigateToCopy;
        throw;
      }

      //return the view that was navigated to
      return view;
    }
  }
}