ArcGIS Server coding practices

The ESRI dev summit was a great experience. Meeting fellow developers is always good - you talk the same language, exchange ideas, receive feedback, discuss how things can be made better,... I could go on and on.

Ok, so I was asked quite a few server related questions at the summit: What should I keep in mind while coding against the server? Any do's and dont's? Any particular classes / methods I should read more about? etc... So here I'll talk about certain points you should keep in mind while working with the ArcGIS Server, particularly the MapServer:

• Use the description objects: Sure the MapServer gives you access to the IMap but you don't have to go there. A lot can be accomplished by using the IMapDescription, ILayerDescription, et al.


• Release the ServerContext: In a pooled environment you are sharing the server object with other users. So it's your responsibility to release the context once you have performed your set of operations. For web applications, this translates to releasing the context after every request. Of course, if you are using the ADF, the ADF does that for you so you need not worry. But even then it's good to keep this in mind.


• Do not reference server objects after the context has been released: Do you continue to work with the Statement object once the JDBC Connection has been closed? NO. Why? Because a Statement can be executed only while the Connection is live. Similarly, you should not reference ANY server objects once you have released the IServerContext. If you want to persist the state of any server object, you should use the saveObject() method to get a serialized string representation of the object before releasing the context. You can once again rehydrate the object by using the loadObject() method once you have regained access to the context.


• In case you had forgotten - use the description objects: Did you know you could add serializable custom graphics to the IMapDescription object?


• Use methods exposed by the MapServer: Look at the javadoc for the MapServer and for all the interfaces that it implements. It can do a lot more than you might think - you can export maps, layouts, do queries, identifies, get feature info, handle SOAP requests, and a whole lot more.


• Create server objects on the server: You don't create RMI objects on the client. You don't create EJBs on the client. Similarly, you don't create ArcGIS server objects on the client. ALWAYS use the IServerContext.createObject() method to create all and any ArcObject in a server application within your server context at the server.


• BTW, use the description objects: Did you know you could change layer visibilities, select features, even set definition expressions with the ILayerDescription object?

This by no means is an exhaustive list but something which might help you when working with the server. Oh yeah, in parting, in case you had missed: use the description objects!

ArcGIS Server 9.2 (Java): Coming soon to a GIS near you

The ESRI User Conference is around the corner and it's time to talk about what the future holds for our users. Before I delve into the details let me say this: ArcGIS Java users, we have heard you! Here's what the future holds for you:

• A pure Java experience: No more query interfacing... no proxies to deal with... The Java programmer will get an API s/he lives by - pure Java... diagnostic exception handling... established design patterns... the whole shebang... you name it we got it!


• A rich SDK experience with Eclipse plug-ins to help you get easily started with using ArcGIS... one click deploy and run of samples... ready to use application templates... code snippets... an integrated and intuitive help system...


• The web tier is being reworked to leverage state of the art technologies (if you are thinking AJAX you are right, but there's MORE)... how about the ability to work with multiple data sources - ArcGIS, ArcIMS, ArcWeb Services... how about the ability to add your custom source... dynamic layer reordering and grouping... network analysis... the list goes on...


• Geoprocessing: You'll get a pure Java experience with GP too - tools, Java data types, geoprocessor, exceptions... You can also build your own custom tool / model, use a tool generator to generate a pure Java class for the same and just like that you are ready to incorporate new GP functionality into your Java GIS.


• OTB EJBs to integrate GIS with your J2EE infrastructure.

All this and more will be discussed at the UC in a couple of sessions:

• ArcGIS Road Ahead: What's Coming for GIS Developers at 9.2
  
  
  
  • Offering I - Wed 8:30 AM Room: 6A (SDCC)
  
  
  • Offering II - Thu 1:30 PM Room: 6A (SDCC)
  
  
  
  


• ArcGIS Road Ahead: What's Coming in ArcIMS and ArcGIS Server at 9.2
  
  
  
  • Offering I - Tue 1:30 PM Room: 6A (SDCC)
  
  
  • Offering II - Thu 8:30 AM Room: 6A (SDCC)
  
  
  
  

I'm sure you are rushing to add them to your agenda! Also, here's the UC Q and A for more info...

See ya!