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     2 <!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->

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     4 "Eclipse Public License v1.0" which accompanies this distribution, 

     5 and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->

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     7     Nokia Corporation - initial contribution.

     8 Contributors: 

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    10 <!DOCTYPE task

    11   PUBLIC "-//OASIS//DTD DITA Task//EN" "task.dtd">

    12 <task id="GUID-BE65B3A7-04E8-5406-B46A-09E2608E0F1F" xml:lang="en"><title>Requesting

    13 Log Engine Notifications </title><shortdesc>This tutorial describes how to request notification from Log Engine. </shortdesc><prolog><metadata><keywords/></metadata></prolog><taskbody>

    14 <context id="GUID-026E70FC-4181-56D2-810A-F9D70BE9A2E7"><p>The Log Engine

    15 records events so that other applications can react to them in ways which

    16 are not part of its own specification. A typical reaction to an event might

    17 be refreshing the screen of the device or causing it to beep, but that is

    18 not Log Engine functionality. The Log Engine notifies other applications of

    19 a change to its database. It provides two interfaces which you implement to

    20 set up notification of changes: </p> <ul>

    21 <li id="GUID-7CE07F32-E2D1-5E2B-A491-4B3DC5CC5F31"><p> <xref href="GUID-37519930-C95E-3FF1-A32D-D42D0A9E710F.dita"><apiname>MLogClientChangeObserver</apiname></xref>  </p> </li>

    22 <li id="GUID-5D5CFA78-7B04-56CD-B919-D0703F1696EF"><p> <xref href="GUID-7DE036FC-7ECE-38FE-8BC0-7B0CA2B3B195.dita"><apiname>MLogViewChangeObserver</apiname></xref>  </p> </li>

    23 </ul> </context>

    24 <steps id="GUID-5E3B8D4C-C912-5E74-8744-44FE6427754F">

    25 <step id="GUID-81E579ED-7379-5ED9-AAD8-F49A0AE50F06"><cmd>Implement <xref href="GUID-37519930-C95E-3FF1-A32D-D42D0A9E710F.dita"><apiname>MLogClientChangeObserver</apiname></xref>  </cmd>

    26 <info> <xref href="GUID-37519930-C95E-3FF1-A32D-D42D0A9E710F.dita"><apiname>MLogClientChangeObserver</apiname></xref> concerns changes which

    27 are global to the database and it has a single member function to be implemented: </info>

    28 <substeps id="GUID-E55DB2B7-A71E-4EB6-8A69-4F4BB5EABE9B">

    29 <substep id="GUID-E509EE1B-92F6-4C45-BFC6-8370BA3FE4AA"><cmd>Implement <xref href="GUID-539F45CB-1182-38EE-A15C-BCD9093AC24F.dita"><apiname>HandleLogClientChangeEventL</apiname></xref> of <xref href="GUID-37519930-C95E-3FF1-A32D-D42D0A9E710F.dita"><apiname>MLogClientChangeObserver</apiname></xref></cmd>

    30 <info>Its arguments are: </info>

    31 <info><ul>

    32 <li id="GUID-393080A5-BAF1-5461-AF2A-46F413C56383"><p> <xref href="GUID-530281E6-29FC-33F2-BC9B-610FBA389444.dita"><apiname>TUid</apiname></xref> aChangeType

    33 the UID of the type of event which occurred </p> </li>

    34 <li id="GUID-73B0B616-C029-52EF-AF31-53996B639051"><p> <xref href="GUID-7A2A43EC-6125-3BFE-834B-23C37F7B40D5.dita"><apiname>TInt</apiname></xref> aChangeParameter1 </p> </li>

    35 <li id="GUID-34CF35D8-6078-587B-A8C1-00337F5C3C31"><p> <xref href="GUID-7A2A43EC-6125-3BFE-834B-23C37F7B40D5.dita"><apiname>TInt</apiname></xref> aChangeParameter2 </p> </li>

    36 <li id="GUID-800AC30F-DF6F-55CF-9455-D49C25F253D0"><p> <xref href="GUID-7A2A43EC-6125-3BFE-834B-23C37F7B40D5.dita"><apiname>TInt</apiname></xref> aChangeParameter3 </p> </li>

    37 </ul></info>

    38 <info>The last three arguments are context-specific: their meaning is specific

    39 to the type of event that occurred. </info>

    40 </substep>

    41 </substeps>

    42 </step>

    43 <step id="GUID-75C55B15-FA43-5E6D-9967-6B6086BCA32B"><cmd/>

    44 <info>Implement <xref href="GUID-7DE036FC-7ECE-38FE-8BC0-7B0CA2B3B195.dita"><apiname>MLogViewChangeObserver</apiname></xref>  </info>

    45 <info> <xref href="GUID-7DE036FC-7ECE-38FE-8BC0-7B0CA2B3B195.dita"><apiname>MLogViewChangeObserver</apiname></xref> concerns changes which are

    46 specific to a database view and it has three member functions to be implemented: </info>

    47 <substeps id="GUID-5645F222-5B4C-4B28-8AC2-F28256821883">

    48 <substep id="GUID-DB5501DF-E345-426E-B13D-5B3CEF840A28"><cmd/>

    49 <info><xref href="GUID-A41FB471-60EC-3786-8CCC-BD35048ED38A.dita"><apiname>HandleLogViewChangeEventAddedL</apiname></xref></info>

    50 </substep>

    51 <substep id="GUID-D68B3B48-8D28-4086-B5FE-B22D622A741C"><cmd/>

    52 <info><xref href="GUID-D799F87B-C0CE-3129-A526-A3B06469B328.dita"><apiname>HandleLogViewChangeEventChangedL</apiname></xref></info>

    53 </substep>

    54 <substep id="GUID-0698E95C-F370-49B5-B43E-176BF5C5F713"><cmd/>

    55 <info><xref href="GUID-6C1A90CC-BA78-3B37-A39C-DC6D1F714654.dita"><apiname>HandleLogViewChangeEventDeletedL</apiname></xref></info>

    56 </substep>

    57 </substeps>

    58 <info>Each of them has the same arguments: </info>

    59 <substeps id="GUID-368850E6-5B7F-4ADB-99ED-F1843BE1340C">

    60 <substep id="GUID-649209D5-146A-445B-B7FF-E67F061148B8"><cmd/>

    61 <info><xref href="GUID-271367A8-DD4F-3A82-AD88-F3E94F2AA980.dita"><apiname>TLogId</apiname></xref> aId </info>

    62 </substep>

    63 <substep id="GUID-982974D3-2D00-40EB-9A32-1F7588390CAA"><cmd/>

    64 <info><xref href="GUID-7A2A43EC-6125-3BFE-834B-23C37F7B40D5.dita"><apiname>TInt</apiname></xref> aViewIndex</info>

    65 </substep>

    66 <substep id="GUID-46F2D7CB-5016-4F08-94DA-12BFFDDD535F"><cmd/>

    67 <info><xref href="GUID-7A2A43EC-6125-3BFE-834B-23C37F7B40D5.dita"><apiname>TInt</apiname></xref> aChangeIndex </info>

    68 </substep>

    69 <substep id="GUID-DF50A88D-DE13-4693-9376-CF6143D8FC7C"><cmd/>

    70 <info><xref href="GUID-7A2A43EC-6125-3BFE-834B-23C37F7B40D5.dita"><apiname>TInt</apiname></xref> aTotalChangeCount</info>

    71 </substep>

    72 </substeps>

    73 </step>

    74 </steps>

    75 <postreq><p>A change to a view typically occurs as part of a sequence of changes,

    76 and the position of the change event record in the view typically reflects

    77 this

    78 fact. 

    79 </p><p>The argument <codeph>aId</codeph> is the Id of the log event in the database.

    80 The argument <codeph>aViewIndex</codeph> is the position in the view

    81 where the event record was added, changed or deleted. The argument

    82 <codeph>aChangeIndex</codeph> is the index of the event in the sequence of

    83 changes. The argument <codeph>aTotalChangeCount</codeph> is the total number

    84 of events in the sequence of changes  

    85 </p></postreq>

    86 </taskbody><related-links>

    87 <link href="GUID-E4A950EA-5671-5755-B3EF-5D6B90E19AE6.dita"><linktext>Maintaining

    88 Log Events</linktext></link>

    89 <link href="GUID-2022F702-9899-5798-8932-D70119C7177D.dita"><linktext>Setting Up

    90 A Log Engine Client</linktext></link>

    91 <link href="GUID-55ECBCF5-FC29-5A4A-A3C6-1CB1C0D562CE.dita"><linktext>Displaying

    92 Log Events</linktext></link>

    93 <link href="GUID-BCB0E50F-B22E-5964-BB68-BEE1870D9C79.dita"><linktext>Configuring

    94 Log Engine </linktext></link>

    95 </related-links></task>