Package io.datarouter.storage.dao

Interface Dao

All Known Implementing Classes:

BaseDao, DatarouterClusterSchemaUpdateLockDao

public interface Dao

A DAO is where nodes are defined. The generic types on each node prevent you at compile time from accidentally saving a databean to the wrong node or requesting a Databean with a PrimaryKey that doesn't match the node. Each DAO could be responsible for multiple physical repositories (for example mysql + sqs + memcached) but it could be limited to a single Databean class. You can inject a DAO into application code for standard operations like get() or putMulti(). Something that manipulates multiple databean classes or adds more complex logic could be named “Service”. Pushing single-databean methods into the DAOs, even if they have complex logic, helps the reader understand the scope of the logic, knowing from the start that it only touches that single databean. This delegation is particularly helpful versus having large services where methods call each other, sometimes obfuscating their effects on multiple tables.