Serialisation, Deserialisation and gson in Open Event Android
JSON is a format to exchange and inter-change data. It has almost become a universal means for transferring data because of it being lightweight, human understandable, machine readable and most importantly, it’s language independence. It can be used with, and in any programming language. (Reference) FOSSASIA’s Open Event project makes extensive use of JSON for transferring information about events, their speakers, sessions and other event information. The Open Event Android application itself loads all it’s data in JSON format. This JSON is uploaded by the user in the form of a .zip compressed file or by giving an API link. Now before we use this data in the app, we have to parse the data to get Java objects that can be used in Android. Deserialisation is the process of converting JSON to Java objects. In the same way, Serialisation refers to converting Java objects into JSON. In most applications and frameworks, JSON is serialized and deserialized on multiple instances. The most common approach is to create objects corresponding to the JSON format and then use functions to convert them to JSON line-by-line, attribute by attribute. While this approach will work, it will mean writing unnecessary code and spending a lot more time on it. In Open-event-Android, we are using Google’s gson library to serialise and deserialise JSON and corresponding Java objects respectively. Why are we using gson specifically? And why do we need any library in the first place? Yes, we can obviously make functions in Java by defining all the JSON parameters and converting the JSON into Java objects manually. It is indeed the obvious approach, but the entire process will be time-consuming, complex and definitely not error-free. Also, as projects become bigger, it is inevitable to take care of the code size and reduce it to only what is necessary. Let’s take a look at the one of the Open Event JSON file as a sample to try and understand things in a better way. This is an example of event.json in the FBF8'2017 sample. { "id": 180, "name": "F8-Facebook Developer Conference 2017", "latitude": 37.329008, "longitude": -121.888794, "location_name": "San Jose Convention Center, 150 W San Carlos St San Jose CA USA 95113 ", "start_time": "2017-04-18T10:00:00-07:00", "end_time": "2017-04-19T10:00:00-07:00", "timezone": "US / Pacific", "description": "Join us for our annual 2-day event, where developers and businesses come together to explore the future of technology. Learn how Facebook connects the world through new products and innovation. This year's event is bigger than ever – with more than 50 sessions, interactive experiences, and the opportunity to meet one-on-one with members of the Facebook team.", "background_image": "/images/background.jpg", "logo": "/images/fbf8.png", "organizer_name": "Facebook", "organizer_description": "Join us for our annual 2-day event, where developers and businesses come together to explore the future of technology. Learn how Facebook connects the world through new products and innovation. This year's event is bigger than ever – with more than 50 sessions, interactive experiences, and the opportunity to meet one-on-one with members of the Facebook team.", "event_url": "https://www.fbf8.com", "social_links": […