I’ve been working on an OData reader in java for some time now, and I am ready to show people the first alpha. There are some pieces missing, and I would prefer better ways of accessing some of the data. But here it is.
The release only has the underived version of the JOCU project. It allows for most of the functionality from the OData protocol (the main one missing is the data format, this uses XML data src as apposed to the json format).
Here is a code snipit I wrote that uses the API from the JAR library.
import java.sql.Timestamp;
import java.util.Date;
import java.util.List;
import lkoutzas.jocu.shared.AbstractCatelogueData;
import lkoutzas.jocu.shared.AbstractEntity;
import lkoutzas.jocu.underived.ODataEntity;
import lkoutzas.jocu.underived.ODataLink;
import lkoutzas.jocu.underived.ODataRepository;
public class RunJOCUDemo {
public static void main(String[] args) {
System.out.println("Welcome to the demo of the JOCU odata reader!!");
System.out.print("Catelogues Start: ");
System.out.println(new Timestamp(System.currentTimeMillis()));
// create the odata repository
ODataRepository oData = new ODataRepository();
// set the URI for the location of the repository
oData.SetURI("http://services.odata.org/OData/OData.svc/");
// get oData Catelogue
List<AbstractEntity> categlogues = oData.FetchODataCatelogues();
System.out.print("End: ");
System.out.println(new Timestamp(System.currentTimeMillis()));
// dump out results to show it works...
System.out.println("Catelogues...");
for(int i=0;i<categlogues.size();i++)
{
AbstractEntity local = categlogues.get(i);
System.out.println(local.getAttribute("href"));
}
System.out.println();
System.out.print("Entities Start: ");
System.out.println(new Timestamp(System.currentTimeMillis()));
// create the odata repository
ODataRepository oData2 = new ODataRepository();
// set the URI for the location of the repository
oData2.SetURI("http://services.odata.org/OData/OData.svc/");
// set the catelogue for the oData repositpory
oData2.SetCatelogue("Categories");
// query or filter the data request (need to detail full list)
oData2.getQuery().top("2").select("ID,Name");
// get entities
AbstractCatelogueData entities = oData2.FetchEntities();
System.out.print("End: ");
System.out.println(new Timestamp(System.currentTimeMillis()));
System.out.println("entities...");
for(int i=0;i<entities.getEntities().size();i++)
{
ODataEntity local = (ODataEntity) entities.getEntities().get(i);
System.out.println(local.field("ID") + ": " + local.field("Name") + " links are: ");
for(int j=0;j< local.getLinks().size();j++)
{
ODataLink odataLink = local.getLinks().get(j);
System.out.println(odataLink.getTitle() + " - " + odataLink.getHref() + " ("+ odataLink.getRelationship()+")");
}
}
}
}
As you can see, the API is pretty easy to use and I think pretty good. So, for the “bits not in the alpha”.
Firstly, there is a bug that will mean that XML structured elements (CDATA as an example) are not parsed correctly. They get broken down into separate elements rather than a single blob.
Also, I would like to improve the manner that the data is being accessed. It feels a bit clunky to me. I am not sure how I can improve it, but I would like to see what I can think of.
The last missing bit / bug is that the expanded entities within the querystring. At the moment I think it would fail badly. The API will allow it, but the data will likely either cause the call to fail or it will will be ignored.
Once these items are in the code, I am going to work on the derived version, which will allow strongly typed objects and (hopefully) reduce the size of the downloaded packet.
The link for the alpha is here. Let me know your thoughts.
