--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Symbian3/SDK/Source/GUID-7809407D-EDC0-5907-B932-0D5726A7ECA2.dita	Thu Jan 21 18:18:20 2010 +0000
@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
+<!-- This component and the accompanying materials are made available under the terms of the License 
+"Eclipse Public License v1.0" which accompanies this distribution, 
+and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
+<!-- Initial Contributors:
+    Nokia Corporation - initial contribution.
+Contributors: 
+-->
+<!DOCTYPE concept
+  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept id="GUID-7809407D-EDC0-5907-B932-0D5726A7ECA2" xml:lang="en"><title>Simple
+encapsulation of a service provider</title><shortdesc>This document describes how to use derived active object classes
+to encapsulate services.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
+<p>Some active object classes do not implement a <codeph>RunL()</codeph> function.
+Such classes are intended for derivation.</p>
+<p>For example, the general purpose <codeph>CTimer</codeph> class provides
+encapsulation of the timer services offered by the <codeph>RTimer</codeph> class,
+but provides no <codeph>RunL()</codeph> to handle their completion. To use
+the <codeph>CTimer</codeph> class, you must derive from it again and provide
+a <codeph>RunL()</codeph> function.</p>
+<p>Some asynchronous service providers may provide facilities for more than
+one request to be outstanding simultaneously. However, a single active object
+can only have one request outstanding. If all the facilities of such an asynchronous
+service provider must be used in a program, then it must be encapsulated by
+more than one active object.</p>
+</conbody></concept>
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