my_custom_deserializers

Kafka deserializers examples to use to demo/test the Conduktor "custom deserializers" feature.

You can download the latest jar containing these deserializers here: my_custom_deserializers_2.13-1.0.0.jar

To learn how to use the "custom deserializer" feature provided by Conduktor, you can read the documentation of the feature: https://docs.conduktor.io/features/consuming-data/custom-deserializers

Deserializers implementation details

Here's the list of the deserializers available in this jar and a quick explanation of each deserializer behaviour.
These deserializers are for demo/test purpose only.

`io.example.conduktor.custom.deserializers.constant.ConstantString`

This deserializer completely ignores the content of the messages it receives from Kafka.
For each message it receives from Kafka, it returns this is a message.

`io.example.conduktor.custom.deserializers.constant.ConstantChar`

This deserializer completely ignores the content of the messages it receives from Kafka.
For each message it receives from Kafka, it returns the letter c.

`io.example.conduktor.custom.deserializers.constant.ConstantInt`

This deserializer completely ignores the content of the messages it receives from Kafka.
For each message it receives from Kafka, it returns the value 1.

`io.example.conduktor.custom.deserializers.constant.ConstantDouble`

This deserializer completely ignores the content of the messages it receives from Kafka.
For each message it receives from Kafka, it returns the value 1.234.

`io.example.conduktor.custom.deserializers.constant.ConstantFloat`

This deserializer completely ignores the content of the messages it receives from Kafka.
For each message it receives from Kafka, it returns the value 1.456.

`io.example.conduktor.custom.deserializers.constant.ConstantShort`

This deserializer completely ignores the content of the messages it receives from Kafka.
For each message it receives from Kafka, it returns the value 2.

`io.example.conduktor.custom.deserializers.constant.ConstantBoolean`

This deserializer completely ignores the content of the messages it receives from Kafka.
For each message it receives from Kafka, it returns the value true.

`io.example.conduktor.custom.deserializers.constant.ConstantByte`

This deserializer completely ignores the content of the messages it receives from Kafka.
For each message it receives from Kafka, it returns the value 6.

`io.example.conduktor.custom.deserializers.constant.ConstantNull`

This deserializer completely ignores the content of the messages it receives from Kafka.
For each message it receives from Kafka, it returns null.

`io.example.conduktor.custom.deserializers.MyCustomDeserializer`

This deserializer transforms the data (bytes) it receives from Kafka into a String (text),
then sees if it matches then following format:

-- this is the serialized data

If the message received from Kakfa effectively starts with a --<space> characters sequence then followed by some text, it creates a new instance of a data structure named MyMessage, that contains only one field named value and is of type String, as following:
```
MyMessage(value = "this is the serialized data")
```
In Conduktor, this data structure will be interpreted and displayed as JSON:
```
{ "value": "this is the serialized data" }
```
If the message received from Kafka doesn't match the expected format, then the deserializer fails with an error message:
```
Invalid format received for message: <the received message>
```

This simple example is here to demonstrate 2 things:

What's happening when a custom deserializer fails to deserialize a message.
Give a simplified example of "deserialization" (the message has to respect of certain format so that the deserializer can extract the data)

bthuillier / my_custom_deserializers