http://www.lenholgate.com/ Len Holgate's thoughts on this and that... Mainly test driven software development in C++ on Windows platforms... - Way back en-us Len.Holgate@JetByte.com 2002-05-30T01:00:00+00:00 hourly 1 2000-01-01T12:00+00:00 http://www.lenholgate.com/archives/000513.html Sometimes it would be nice to be able to use a simple C++ object as a sink for Connection Point notifications. This article shows you how.... Posted by Len at 01:00 AM | Comments (2) | Categories: Reprints , Source Code , Way back ]]> 513@http://www.lenholgate.com/ Reprints 2002-05-30T01:00:00+00:00 http://www.lenholgate.com/archives/000514.html This example COM component provides three COM objects for using the Win32 Mailslot IPC mechanism. The component may be useful if you need to communicate from VB using Mailslots. However, the reason I wrote it was to demonstrate creating a... Posted by Len at 01:00 AM | Comments (0) | Categories: Reprints , Source Code , Way back ]]> 514@http://www.lenholgate.com/ Reprints 2002-04-11T01:00:00+00:00 http://www.lenholgate.com/archives/000460.html A "generic" AVL Tree, from the dark days before templates... The code here is some of my first C++. Back in 1991 C++ was still pretty new. Looking back at my early C++ is better than looking back at my... Posted by Len at 11:31 AM | Comments (2) | Categories: Reprints , Source Code , Way back ]]> 460@http://www.lenholgate.com/ Reprints 2001-08-07T11:31:56+00:00 http://www.lenholgate.com/archives/000459.html In 1989 I taught myself C to write an adventure game, the code's fairly bad, but 10 year's later, the game's still quite cool!... Posted by Len at 11:25 AM | Comments (0) | Categories: Reprints , Source Code , Way back ]]> 459@http://www.lenholgate.com/ Reprints 2001-08-02T11:25:01+00:00 http://www.lenholgate.com/archives/000335.html A common way to improve the performance of Java code is to cache objects rather than repeatedly create and destroy them. This is especially true when you're writing middle tier servers that service client requests and return results objects. Implementing a flexible caching scheme in Java is relatively easy, but there are a few things to watch for. Posted by Len at 08:18 PM | Comments (5) | Categories: Reprints , Source Code , Way back ]]> 335@http://www.lenholgate.com/ Way back 2001-07-26T20:18:27+00:00 http://www.lenholgate.com/archives/000478.html When a CORBA server allows its clients to create and destroy objects one of the recommended ways to handle the object lifetime issues is using the Evictor Pattern. In The Evictor Pattern we solved the problem for C++ servers, here... Posted by Len at 01:00 AM | Comments (0) | Categories: Reprints , Source Code , Way back ]]> 478@http://www.lenholgate.com/ Reprints 2001-07-23T01:00:00+00:00 http://www.lenholgate.com/archives/000477.html One way of making a reference counted implementation more robust is to run the keep-alive protocol yourself. We demonstrate this option here.... Posted by Len at 01:00 AM | Comments (0) | Categories: Reprints , Source Code , Way back ]]> 477@http://www.lenholgate.com/ Reprints 2001-03-17T01:00:00+00:00 http://www.lenholgate.com/archives/000476.html Since CORBA doesn't really support reliable reference counting implementations we'll compare one of the recommended methods of servant life-time management with our reference counted iteration interface.... Posted by Len at 01:00 AM | Comments (0) | Categories: Reprints , Source Code , Way back ]]> 476@http://www.lenholgate.com/ Reprints 2001-03-15T01:00:00+00:00 http://www.lenholgate.com/archives/000475.html A CORBA style method of enumeration can be seen in the iteration interfaces on the CORBA Naming Service. Given the code we've already written for the enumeration interface we can easily implement an iteration interface as well as (or, more... Posted by Len at 02:00 AM | Comments (0) | Categories: Reprints , Source Code , Way back ]]> 475@http://www.lenholgate.com/ Reprints 2001-02-09T02:00:00+00:00 http://www.lenholgate.com/archives/000469.html CORBA provides sequences as a way of returning collections of items from an method call. The problem with just using unbounded sequences is that the client has no control over how many items it receives as a result of the call. COM gets around this problem using the IEnum style interfaces that allow a client to control how it accesses the items in a collection. Posted by Len at 01:00 AM | Comments (0) | Categories: Reprints , Source Code , Way back ]]> 469@http://www.lenholgate.com/ Reprints 2001-02-09T01:00:00+00:00 http://www.lenholgate.com/archives/000468.html At the end of the second article we have developed a self contained reference counting implementation that appears to work. Unfortunately, it's still far from reliable as CORBA doesn't provide the level of support for reference counting that's built into COM. In this article we discuss the problem and the various CORBA methods for controlling server object lifetime. Posted by Len at 12:00 AM | Comments (0) | Categories: Reprints , Way back ]]> 468@http://www.lenholgate.com/ Reprints 2001-02-09T00:00:00+00:00 http://www.lenholgate.com/archives/000467.html Although we managed to develop a working solution in the first CORBA reference counting article the results were ugly and fragile. In this article we attempt to clean things up a little and, in doing so, get intimate with the Portable Object Adapter and its Servant Managers. Posted by Len at 01:00 AM | Comments (0) | Categories: Reprints , Source Code , Way back ]]> 467@http://www.lenholgate.com/ Reprints 2001-02-06T01:00:00+00:00 http://www.lenholgate.com/archives/000343.html We've been developing code on Windows and Unix for quite some time, but most of the distributed component work we've been involved in has been done using COM. That's changing now as clients have more requirements for Unix based component solutions. We're currently evaluating CORBA ORBs and learning how the CORBA way of doing things differs from the COM way. The first difference that we came across was the way that CORBA servers deal with object lifetime issues. Adding reference counting to CORBA objects isn't as easy as it first seems Please note that these articles initially explore COM concepts implemented in CORBA, some of the early implementations, whilst working examples, aren't at all production quality... If you want something reliable, that works, skip forward to the Evictor Pattern. Posted by Len at 12:00 AM | Comments (0) | Categories: Reprints , Source Code , Way back ]]> 343@http://www.lenholgate.com/ Reprints 2001-02-06T00:00:00+00:00 http://www.lenholgate.com/archives/000521.html COM+ applications can be complex to configure and there's no standard way to save that configuration in a form that can be placed under version control. Luckily the COM+ Catalog is accessible by a set of completely scriptable COM objects.... Posted by Len at 01:00 AM | Comments (0) | Categories: Reprints , Source Code , Way back ]]> 521@http://www.lenholgate.com/ Reprints 2000-06-29T01:00:01+00:00 http://www.lenholgate.com/archives/000546.html If you are going to use the client cursor engine then often it's a good idea to disconnect your recordset...... Posted by Len at 01:00 AM | Comments (0) | Categories: Reprints , Source Code , Way back ]]> 546@http://www.lenholgate.com/ Source Code 2000-05-21T01:00:01+00:00 http://www.lenholgate.com/archives/000552.html How to package lots of standard functionality into a CListBox derived class.... Posted by Len at 01:00 AM | Comments (0) | Categories: Reprints , Source Code , Way back ]]> 552@http://www.lenholgate.com/ Source Code 2000-02-26T01:00:02+00:00 http://www.lenholgate.com/archives/000550.html Localise design decisions by writing key application functionality as pluggable COM objects. When the requirements change you just write a new plug in...... Posted by Len at 01:00 AM | Comments (0) | Categories: Reprints , Way back ]]> 550@http://www.lenholgate.com/ Reprints 2000-02-26T01:00:01+00:00 http://www.lenholgate.com/archives/000551.html It's rare that code can be viewed as a black box for reuse. If you include design choices and dependencies as valid parts of the code's interface then it's easier to explain why reusing nontrivial code is often harder than... Posted by Len at 01:00 AM | Comments (0) | Categories: Reprints , Way back ]]> 551@http://www.lenholgate.com/ Reprints 2000-02-01T01:00:01+00:00 http://www.lenholgate.com/archives/000545.html Making the ADO Client Cursor Engine believe that your rowset is updateable involves jumping through a few extra hoops...... Posted by Len at 01:00 AM | Comments (0) | Categories: Reprints , Source Code , Way back ]]> 545@http://www.lenholgate.com/ Source Code 2000-01-02T01:00:02+00:00 http://www.lenholgate.com/archives/000544.html The ATL OLE DB Provider templates only seem to support read-only rowsets, and making them support updating of data isn't as easy as you'd expect!... Posted by Len at 01:00 AM | Comments (0) | Categories: Reprints , Source Code , Way back ]]> 544@http://www.lenholgate.com/ Source Code 2000-01-02T01:00:01+00:00 http://www.lenholgate.com/archives/000543.html Adding bookmark functionality is relatively easy and it enables our ADO recordset to be used with a greater number of data bound controls.... Posted by Len at 01:00 AM | Comments (0) | Categories: Reprints , Source Code , Way back ]]> 543@http://www.lenholgate.com/ Source Code 1999-10-16T01:00:01+00:00 http://www.lenholgate.com/archives/000542.html The ATL OLE DB Provider templates appear to rely on the fact that your data is kept in a simple array, but that's not really the case at all!... Posted by Len at 01:01 AM | Comments (0) | Categories: Reprints , Source Code , Way back ]]> 542@http://www.lenholgate.com/ Source Code 1999-09-15T01:01:01+00:00 http://www.lenholgate.com/archives/000541.html ADO seems to be the ideal way to expose tabular data from your own COM objects and the ATL OLE DB Provider templates can help!... Posted by Len at 01:00 AM | Comments (0) | Categories: Reprints , Source Code , Way back ]]> 541@http://www.lenholgate.com/ Source Code 1999-09-15T01:00:01+00:00 http://www.lenholgate.com/archives/000554.html Templates are a great way of reusing code, unfortunately MFC makes it hard to write MFC friendly template classes...... Posted by Len at 01:01 AM | Comments (0) | Categories: Reprints , Source Code , Way back ]]> 554@http://www.lenholgate.com/ Source Code 1998-09-30T01:01:01+00:00 http://www.lenholgate.com/archives/000512.html COM objects generally provide access to sequences using an IEnumXXXX style interface, this class wraps that with an STL style iterator... Posted by Len at 01:00 AM | Comments (0) | Categories: Reprints , Source Code , Way back ]]> 512@http://www.lenholgate.com/ Reprints 1998-09-30T01:00:01+00:00 http://www.lenholgate.com/archives/000093.html In February 1995 I flew to Perm in eastern Russia as part of a two-man team installing a smartcard system for a local bank. I was responsible for designing and implementing the card production system that was being used. For... Posted by Len at 08:21 AM | Comments (0) | Categories: Geek Speak , Way back ]]> 93@http://www.lenholgate.com/ Way back 1995-02-25T08:21:09+00:00 http://www.lenholgate.com/archives/000019.html This character sketch is from a Rifts scenario that I made notes for but never got around to running. Posted by Len at 07:17 AM | Comments (0) | Categories: Role Playing , Way back ]]> 19@http://www.lenholgate.com/ Way back 1993-04-08T07:17:22+00:00 http://www.lenholgate.com/archives/000035.html The Order of the Silver Rose was a religious order of Knights in an AD&D campaign that I ran. The campaign was set in The Forgotten Realms and was based around the FRE1-3 scenario packs. Posted by Len at 10:24 PM | Comments (1) | Categories: Role Playing , Way back ]]> 35@http://www.lenholgate.com/ Way back 1992-02-07T22:24:15+00:00