TB9.2 Example Applications: examples/Base/IPC/pubsub/subscribepe.cpp Source File

00001 // Copyright (c) 2008-2009 Nokia Corporation and/or its subsidiary(-ies).
+00002 // All rights reserved.
+00003 // This component and the accompanying materials are made available
+00004 // under the terms of "Eclipse Public License v1.0"
+00005 // which accompanies this distribution, and is available
+00006 // at the URL "http://www.eclipse.org/legal/epl-v10.html".
+00007 //
+00008 // Initial Contributors:
+00009 // Nokia Corporation - initial contribution.
+00010 //
+00011 // Contributors:
+00012 //
+00013 // Description:
+00014 // Demonstrates the pure event pattern of subscribing to an integer property
+00015 //
+00016 
+00017 
+00018 
+00023 #include "subscribepe.h"
+00024 
+00025 LOCAL_D CConsoleBase* console;
+00026 
+00030 CIntPropertyWatch::CIntPropertyWatch():CActive(EPriority)
+00031         {
+00032         }
+00033 
+00038 void CIntPropertyWatch::ConstructL(CConsoleBase* aConsole)
+00039         {
+00040         User::LeaveIfError(iProperty.Attach(KMyPropertyCat,KMyPropertyName));
+00041         iConsole = aConsole;
+00042         CActiveScheduler::Add(this);
+00043         }
+00044 
+00050 CIntPropertyWatch* CIntPropertyWatch::NewL(CConsoleBase* aConsole)
+00051         {
+00052         CIntPropertyWatch* self = new (ELeave) CIntPropertyWatch;
+00053         CleanupStack::PushL(self);
+00054         self->ConstructL(aConsole);
+00055         CleanupStack::Pop(self);
+00056         return self;
+00057         }
+00058 
+00062 CIntPropertyWatch::~CIntPropertyWatch()
+00063         {
+00064         iProperty.Close();
+00065         Cancel();
+00066         }
+00067 
+00071 void CIntPropertyWatch::DoCancel()
+00072         {
+00073         iProperty.Cancel();
+00074         }
+00075 
+00080 void CIntPropertyWatch::RunL()
+00081         {
+00082         // Receive a notification when a value is published
+00083         // The RProperty::Get() function call can be omitted as the published value is of no importance in the pure event pattern
+00084         TInt value;
+00085         TInt err = iProperty.Get(value);
+00086         if (err == KErrNotFound)
+00087                 {
+00088                 // No need to re-subscribe to the property as it has been deleted by the publisher
+00089                 CActiveScheduler::Stop();
+00090                 }
+00091         else if (err == KErrNone)
+00092                 {
+00093                 // Print the value of the property
+00094                 PrintProperty(value);
+00095                 // Re-subscribe to the property
+00096                 IssueRequest();
+00097                 }
+00098         else
+00099                 {
+00100                 // Leave the function in case of any other error
+00101                 CActiveScheduler::Stop();
+00102                 User::Leave(err);
+00103                 }
+00104         }
+00105 
+00110 void CIntPropertyWatch::PrintProperty(TInt aValue)
+00111         {
+00112         iConsole->Printf(KTxtValChange,aValue);
+00113         }
+00114 
+00119 void CIntPropertyWatch::WatchL()
+00120         {
+00121         TInt value;
+00122         // Checks if the property exists
+00123         TInt res = iProperty.Get(value);
+00124         if (res == KErrNotFound)
+00125                 {
+00126                 // Property not defined
+00127                 User::Leave(res);
+00128                 }
+00129         // Prints the value of the property
+00130         // This is only to illustrate that the value of the property is set by the publisher
+00131         // This value has no significance as the pure event distribution pattern of publish and subscribe is being followed
+00132         PrintProperty(value);
+00133         IssueRequest();
+00134         }
+00135 
+00139 void CIntPropertyWatch::IssueRequest()
+00140         {
+00141         iProperty.Subscribe(iStatus);
+00142         SetActive();
+00143         }
+00144 
+00145 void DoExampleL()
+00146         {
+00147         CActiveScheduler* scheduler = new (ELeave) CActiveScheduler();
+00148         CleanupStack::PushL(scheduler);
+00149         CActiveScheduler::Install(scheduler);
+00150 
+00151         console->Printf(KTxtPESub);
+00152 
+00153         // Create the integer property watch active object
+00154         CIntPropertyWatch* obj = CIntPropertyWatch::NewL(console);
+00155         CleanupStack::PushL(obj);
+00156 
+00157         // Subscribe to the property and start the scheduler
+00158         obj->WatchL();
+00159         CActiveScheduler::Start();
+00160 
+00161         CleanupStack::PopAndDestroy(obj);
+00162         CleanupStack::PopAndDestroy(scheduler);
+00163         }
+00164 
+00165 GLDEF_C TInt E32Main()
+00166         {
+00167         __UHEAP_MARK;
+00168         CTrapCleanup* cleanup = CTrapCleanup::New();
+00169 
+00170         TRAPD(createError, console = Console::NewL(KTextConsoleTitle, TSize(KConsFullScreen,KConsFullScreen)));
+00171         if (createError)
+00172                 return createError;
+00173 
+00174         TRAPD(mainError, DoExampleL());
+00175         if (mainError)
+00176                 console->Printf(KTextFailed, mainError);
+00177         console->Printf(KTextPressAnyKey);
+00178         console->Getch();
+00179 
+00180         delete console;
+00181         delete cleanup;
+00182         __UHEAP_MARKEND;
+00183         return KErrNone;
+00184         }
+