First Steps

The following text describes how to use the flattr4j API for the most common use cases.

Getting a FlattrService

In order to use the Flattr REST API, a FlattrService instance needs to be created. A description can be found here. To get access, the OAuth Procedure needs to be taken first. It results in an access token.

Languages and Categories

Flattr only accepts a certain set of Languages and Categories. There are two methods to retrieve them:

List<Language> languages = flattrService.getLanguages();
List<Categories> categories = flattrService.getCategories();

These lists are publically available, so they can be retrieved by OpenService. The advantage of OpenService is that no OAuth Procedure is required.

Accessing Things and Users

Things and Users can be accessed by getThing() and getUser(), respectively. These methods can be used when only the Thing’s or User’s ID is known, but also when more details about a Thing or User is needed. In order not to clutter the service API, these methods use an ID interface as parameter, so all objects that implement an ID interface can be passed in. But let me give some examples.

The following line will fetch a Thing with ID 12345.

Thing thing = flattrService.getThing(Thing.withId("12345"));

Thing.withId() returns a plain object that only implements the ThingId interface. It can be used on all methods that take a ThingId when only the ID of a Thing is known.

Now, the following code will submit a click on a Thing with ID 12345:

Thing thing = flattrService.getThing(Thing.withId("12345"));;

A Thing object implements the ThingId interface itself, so it can be passed to methods that require a ThingId as argument, too. Alternatively, instead of the two lines above it is possible to submit the click just by a single line:"12345"));

There are also ID interfaces for User, Category and Language objects which can be used in a similar way.

Submitting Things

Of course, it is also possible to submit new Things by using the FlattrService. To do so, a Submission object needs to be created and populated:

Submission sub = new Submission();
sub.setTitle("First Steps");
sub.setDescription("How to use flattr4j");

The new Thing is submitted by calling create():

ThingId newThingId = flattrService.create(sub);

As you may have noticed, the setCategory() and setLanguage() methods accept CategoryId and LanguageId interfaces, respectively. Instead of using the withId() construction, it is also possible to pass in an object that was returned by getCategories() or getLanguages().

More fun with ID interfaces

Many other model objects of flattr4j also implement ID interfaces. For example, it’s very easy to put an extra click on all the Things that have been flattred by the logged-in user, because Flattr implements the ThingId interface for the Thing that was flattred:

for (Flattr flattr : flattrService.getMyFlattrs()) {;

But there are also ways that are not that obvious. For example, a Thing implements the UserID interface for the user who submitted the Thing. The following lines will get details of the User who submitted the Thing with ID 12345:

Thing thing = flattrService.getThing(Thing.withId("12345"));
User user = flattrService.getUser(thing);

It is also possible to implement ID interfaces in own classes, like database entities. This way, the own classes can be passed to the service methods as well. For example, to get a Thing object for a blog article that is stored in a database, the code would be something like:

BlogArticle article = blogService.getArticle(5678); // BlogArticle implements ThingId
Thing thing = flattrService.getThing(article);