Using Excel as a Real-Time client for Coherence
By dxfelcey on Mar 13, 2009
Often Coherence is thought of as a Java data caching product, and the server side component – where the data is kept is. But the client can not only be a Java application, it can also be a native .NET or C++ application. The native C++ application can also run on Windows, Linux or Solaris. So getting back to .NET. Since the .NET client is just a native C# or VB.NET application (no Java) you can do some nice things, like use the Real Time Data (RTD) Server API to integrate it with Excel, turning Excel into a real-time Coherence client. If you want to see a flash demonstration then click here to view it in action.
The screen shot of the demonstration shows how a constantly updating graph (shown below) of stock price information can be displayed in Excel. The data which is constantly changing, in this case stock prices, is held in a Coherence cache. A separate client application is changing the stock prices and these changes in the data cache are then being pushed to the .NET Coherence client (RTD Server) and on to the Excel spreadsheet.
The RTD Server is a C# .NET client packaged as an .NET Assembly/DLL and then registered as a COM object. The example in the demonstration is pretty flexible but the next version will be enhanced to provide a great range of filtering.
Now the example being shown in the demonstration is a first cut (developed with help from Aleksandar Seovic). An improved version will be published very soon with a fuller explanation about it works along with the code itself.