Harald Pehl

Developer notes written down before they get lost.

Restlet Extension for Piriti

Restlet is a RESTful Web framework for Java. There’s also a GWT edition available. The Piriti Restlet extensions is built on top of that edition. Therefore the 2.x version of Restlet is used. There are two representations available which use the Piriti readers to convert JSON and XML data to your model (POJOs and/or GXT models).

Read and convert JSON

To read the JSON data you need an instance of JsonReader:

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public class Book
{
    interface BookReader extends JsonReader<Book> {}
    public static final BookReader JSON = GWT.create(BookReader.class);

    // Fields annotated with @JsonField
    ...
}

Then you can read the JSON data like this:

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ClientResource clientResource =
    new ClientResource("/resource/with/json/representation");

clientResource.setOnResponse(new Uniform()
{
    @Override
    public void handle(Request request, Response response)
    {
        PiritiJsonRepresentation<Book> representation =
            new PiritiJsonRepresentation<Book>(Book.JSON, response.getEntity());
        try
        {
            // Depending whether there's one book or an array of books
            // in your JSON data
            List<Book> books = representation.getModels();
            Book book = representation.getModel();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }
});

clientResource.get(MediaType.APPLICATION_JSON);

The entity returned by the resource has to be a valid JSON object. In case you want to read a list of books, the JSON object has to contain one key (name does not matter) with the array of books:

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{books: [{isbn: "0815", title: "Foo"}, {isbn: "1234", title: "Bar"}]}

Read and convert XML

To read the XML data you need an instance of XmlReader

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public class Book
{
    interface BookReader extends XmlReader<Book> {}
    public static final BookReader XML = GWT.create(BookReader.class);

    // Fields annotated with @XmlField
    ...
}

Then you can read the XML data like this:

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ClientResource clientResource =
    new ClientResource("/resource/with/xml/representation");

clientResource.setOnResponse(new Uniform()
{
    @Override
    public void handle(Request request, Response response)
    {
        PiritiXmlRepresentation<Book> representation =
            new PiritiXmlRepresentation<Book>(Book.XML, response.getEntity());
        try
        {
            // Depending whether there's one book element or a list of book
            // elements in your XML data
            List<Book> books = representation.getModels();
            Book book = representation.getModel();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }
});

clientResource.get(MediaType.TEXT_XML);

The entity returned by the resource has to be a valid XML document. In case you want to read a list of books, the document must contain a list of book elements as direct children of the root element:

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<books>
    <book>
        <isbn>0815</isbn>
        <title>Foo</title>
    </book>
    <book>
        <isbn>1234</isbn>
        <title>Bar</title>
    </book>
</books>

Further information

If you want to learn more about Piriti and its extensions, please feel free to take a look at it under https://github.com/hpehl/piriti