CODEWITHSUNDEEP
javamuleodataodata4jolingo
TomD
TomD

Reputation: 108

Odata with Olingo or Odata4j

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

Answers (2)

prerna30
prerna30

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

Richard Donovan
Richard Donovan

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

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