How would you organize the delete method?

The implementation of the delete method depends on the specific context:

• Deletion by ID: The most common case. The method takes an object identifier and deletes it from the storage.

  public void delete(Long id) {
      // Check for object existence by ID
      // Remove object from database or other storage
      // Handle errors (e.g., if object with such ID is not found)
  }
  

• Deletion by object: The method takes the object itself and deletes it from storage. Requires that the object is "managed" or tracked by the storage.

  public void delete(MyObject object) {
      // Remove object from database or other storage
      // Check for object existence
      // Handle errors
  }
  

• Filtering for deletion: The method takes criteria (e.g., specification, filter) and deletes all objects matching these criteria.

  public void delete(Specification<MyObject> spec) { // Example with JpaSpecificationExecutor
      // Select objects by specification
      // Delete selected objects
      // Handle errors
  }
  

Important considerations:

• Transactional: The delete operation should be atomic.
• Error handling: Handle cases when the object to delete does not exist.
• Logical deletion: Sometimes, instead of physical deletion, a flag isDeleted is used.
• Cascade delete: Deleting one object may lead to deletion of related objects. This should be explicitly managed.
• Access rights: Check if the caller has permission to delete.

Example implementation in Spring Data JPA repository:

import org.springframework.data.jpa.repository.JpaRepository;

public interface MyObjectRepository extends JpaRepository<MyObject, Long> {

    // Implementation is provided by Spring Data JPA
    void deleteById(Long id);
    void delete(MyObject entity);
}