[tasque/transition: 101/213] Make TaskNote.Text concrete

[Antonius Riha <antoniusri src gnome org>]

commit 3eb41ad5bd12577091dd5b3bbdcbb1f05741196f
Author: Antonius Riha <antoniusriha gmail com>
Date:   Thu Aug 16 13:37:03 2012 +0200

    Make TaskNote.Text concrete
    
    * Text.Setter: prohibit null values for Text
    * OnTextChanged: Add change hook for child classes

 src/libtasque/TaskNote.cs |   19 ++++++++++++++++++-
 1 files changed, 18 insertions(+), 1 deletions(-)
---
diff --git a/src/libtasque/TaskNote.cs b/src/libtasque/TaskNote.cs
index a20b55c..89eb34f 100644
--- a/src/libtasque/TaskNote.cs
+++ b/src/libtasque/TaskNote.cs
@@ -33,6 +33,23 @@ namespace Tasque
 {
 	public abstract class TaskNote
 	{
-		public abstract string Text { get; set; }
+		protected TaskNote (string text)
+		{
+			Text = text;
+		}
+		
+		public string Text {
+			get { return text; }
+			set {
+				if (value == null)
+					throw new System.ArgumentNullException ("text");
+				text = value;
+				OnTextChanged ();
+			}
+		}
+		
+		protected virtual void OnTextChanged () {}
+		
+		string text;
 	}
 }