Reputation: 108
I'm in over my head.
At the broadest level, I'm trying to expose an Odata interface to an existing pool of data exposed by a service written using Mule. When my Mule service is invoked, if I detect that the URL is Odata format, I want to delegate processing down to something written in Java and then feed the response from that component back to my caller.
I found the Olingo and OData4j libraries. My problem is that these start from building a Web service. But that's too far upstream for me. I have a Web service. What I need to understand are what components I need to implement in order to pass the URL (which I have in hand) onward to an Odata parser which will, in turn, invoke a data provider.
I'm a bit lost with this technology. Can someone point me to a very basic tutorial that clearly delineates this. Or, can they give me a couple steps like: "You have to implement A, B & C and then pass your URL into C.foo()"?
I've tried the Getting Started doc for both libraries but they both start with "first we'll implement a Web service" and don't clearly delineate (to me, at least) where that leaves off and pure Odata sets in.
Thanks.
Upvotes: 5
Views: 4581
Reputation: 141
The following is the code that will help you to get started for using data from a service exposing via OData.(using Apache Olingo).
URL url=new URL(/*your url*/);
HttpURLConnection conn=(HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");
conn.setRequestProperty(HttpHeaders.ACCEPT,HttpContentType.APPLICATION_XML);
conn.connect();
InputStream content=conn.getInputStream();
Edm edm = EntityProvider.readMetadata(content, false);
After this you can use static methods of EntityProvider class for carrying out various operations like read,update,write
If you are using odata4j go with the following code
ODataConsumer demo_consumer= ODataConsumers.create(/*your URL*/);
Enumerable<EntitySetInfo> demo_entitySetList = demo_consumer.getEntitySets();
for (EntitySetInfo entitySet : entitySetList) {
System.out.println(entitySet.getHref());
}
Upvotes: 4
Reputation: 425
this sounds very like how we read rss or other data feeds
Since you have a url, this can be read by a Http Connector or even a polling http connector. The data can be streamed using a Java input stream the default behavior or converted to a string (object to string).
A simple java component using (OData4j) can process your content .. it sounds like 2 simple components on a mule flow.
R
Upvotes: -2