Event driven application

Many applications listen to multiple event sources, update the state of corresponding business entities, and have to execute actions if some state is reached. Cadence is a good fit for many of these. It has direct support for asynchronous events (aka signals), has a simple programming model that obscures a lot of complexity around state persistence, and ensures external action execution through built-in retries.

Samples

Runnable event-driven samples:

Sample	Description	Code
Signal handling	Workflow that waits for and reacts to external signals	Go · Java
Event accumulation	Counter workflow that accumulates signal events, like the loyalty-points example below	Go
Signal and response	Sends a signal to a workflow and reads back its response	Java

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Real-world examples:

• Fraud detection where workflow reacts to events generated by consumer behavior
• Customer loyalty program where the workflow accumulates reward points and applies them when requested