Query using BlazeDS / WebService

Question

Hi everybody,

I have a question about querying data using remote services. My maps exist on our ArcGIS server, but the data which is not geospatially enabled is coming from a MS SQL Server 2008, and now I am wondering what's the best way to perform a query that connects the two? ArcSDE is one possible way I suppose, but how do you handle data that comes in via Webservice calls or BlazeDS? I want to draw features based on data from the remote service. So a simple example would be if the data in a certain field is between numbers 1 and 2, the feature would turn green. Can anyone guide me to some examples on how to use blazeDS with ArcGIS, and how to query based on that data?  I have no experience in this area so any help would be greatly appreciated!

Thanks,
Alex

Alexandervan_der_Schans · Answer

Thanks Rene!

This will give me some good starting points. I will definetly check out the resources you posted, since I already felt that the blazeDS/webORB route might be the way to go for us. One last question though, how do set the color of the flowlines in your application? Do you just loop over the results from the query, and then bind the result to a ClassBreakRenderer? I don't know if there would be another way to do this.

thanks!

ReneRubalcava · Answer

My java experience is pretty limited to just database access and queries. To access SQL Server, you'll need the sqljdbc4.jar from Microsoft. One thing I am doing in that query is turning my results into a custom object I call FlowControl, which is a pretty simple Java object, but what it allows me to do is quickly serialize those objects in Flex by adding this metadata tag to a class
[RemoteClass(alias="SewerDb.dto.FlowControl")]
public class FlowControl...

So your Flex object matches your Java object.
There are lots of materials on Adobe's website and elsewhere on using BlazeDS with Flex.
http://www.adobe.com/devnet/livecycle/articles/blazeds_spring.html

One book that I really like that just recently went into print is Flex On Java, which covers the subject really well.

If however, you are like me and prefer working in a .NET environment, you can use WebOrb for .NET, which is a great solution for tasks like this. A great benefit of WebOrb is the WebOrb console which will let you test your functions as well provide you the Actionscript code you would need to use the functions. It has fantastic code generation tools that you can use to learn from.

Using RemoteObjects requires slightly more setup initially to access backend data, but it absolutely worth it in the end. We have one function to perform flow tracing that can return a few thousand records that is done via a WebOrb AMF endpoint, and as a regular WSDL web service it took up to 2 minutes to return results and we can now show the query results in less than 10 seconds.

Alexandervan_der_Schans · Answer

Yes, the data matches based on Unique identifiers. Your solution is actually one I am looking for, but I am not experienced in java programming. Would you say it is hard to pick up and learn or does it only take minimal java programming skills? From your example I dont quite understand though how the data returned from the java query enters Flex. Does the flex application communicate with blazeDS via the RemoteObject and how?