DD4T with java using OData

Question

I am using DD4T with java using odata web service. I am able to retrieve the content of whole page in java using odata. But I am not sure how can we get the values of individual elements to create the JSP pages. I have created Odata client and then used below code to retrieve content from odata:

String filter = String.format("PublicationId eq %d and Url eq '%s'", 176, "/example/test.html");

OEntity pageEntity1 = ODataClient.INSTANCE.getPageEntities().filter(filter).expand("PageContent").execute().firstOrNull();

OEntity pageContentEntity = pageEntity1.getLink("PageContent", OLink.class). getRelatedEntity();

System.out.println(pageContentEntity.getProperty("Content", String.class).getValue());

But this is giving content of whole page. I want content of individual field of component.

Answer 1

The code you pasted is part of the Page provider, as I highlighted on my blog post http://yatb.mitza.net/2014/06/odata-page-provider-dd4t-java.html. This code is solely responsible to handle communication with the CD Webservice (aka OData).

The provider is called by the PageFactory, which is responsible for 3 things:

• handling caching, so you don't hit OData for every request
• retrieval of the Page content from the provider (as a String representing a model serialized by the templates)
• deserializing the content into a DD4T model object

So what you are missing is the PageFactory method getPageFromSource, which deserializes the page content into a GenericPage.

There are a number of XML/JSON serializers out there, so you can simply pick one and implement. In my latest project we used Jackson to handle JSON. A sample invoker to deserialize is:

public GenericPage getPageFromSource(String source) throws SerializationException {
    return SerializerFactory.deserialize(source, PageImpl.class);
}

The SerializerFactory returns a Serializer that uses Jackson API

/**
 * Jackson's 2.3.3 ObjectMapper
 */
private static final ObjectMapper mapper = new ObjectMapper();

@Override
public <T> T deserialize(final String content, final Class<T> aClass) throws SerializationException {
    try {
        return mapper.readValue(content, aClass);
    } catch (IOException e) {
        throw new SerializationException(e);
    }
}

Answer 2

I can only assume that the content of the Components is available in the Component Presentations within that page, so you should probably expand your query to return the ComponentPresentations (something like odata.svc/Pages(PublicationId eq 123, Id eq 234)/ComponentPresentations))