package Lab.Service;

import Lab.Exceptions.InvalidTonnageException;

import Lab.Model.Ship;

import Lab.Repository.ShipRepository;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

import org.springframework.transaction.annotation.Transactional;

import java.util.ArrayList;

import java.util.List;

$/**$

$*$ TODO: Using the Transactional annotation, cause the methods of this Service class to roll back the current

$*$ database transaction when the InvalidTonnageException is thrown. This will wrap all

$*$ methods in this class inside of a database transaction, which will prevent incomplete updates in the event of an

$*$ exception being thrown. It should be assigned to rollback the transaction for some exception, hence the rollbackFor.

$*$ You can test this by attempting to persist a list of ships where some ship in the JSON has a negative tonnage, then

$*$ attempting to get all ships. No ships should be persisted if any ship in the array has a negative or zero

$*$ tonnage $-$ we're left to assume some form of unwanted user error in that case.

$*/$

@Service

public class ShipService $\{$

$$ ShipRepository shipRepository;

$$ @Autowired

$$ public ShipService$($ShipRepository shipRepository$)\{$

$$ this.shipRepository $=$ shipRepository;

$\}$

$/**$

$*$ this is a bad way to save a list to the repository as you can just use the $.$saveAll method provided the table

$*$ has a CHECK constraint to check tonnage, but this gets the point across for the importance of @Transactional

$*$ @param ships transient ship entities

$*$ @throws InvalidTonnageException ships can not have negative tonnage $($they$\text{'}$d sink$)$

$*/$

$$ public List addListShips$($List ships$)$ throws InvalidTonnageException $\{$

$$ List persistedShips $=$ new ArrayList$<>()$;

$$ for$($int i $=0$; i $<$ ships.size$()$; i$++)\{$

$$ if$($ships$.$get$($i$).$getTonnage$()<=0)\{$

$$ throw new InvalidTonnageException$()$;

$\}$

$$ persistedShips.add$($shipRepository$.$save$($ships$.$get$($i$)))$;

$\}$

$$ return persistedShips;

$\}$

$/**$

$*$ @return all ship entities

$*/$

$$ public List getAllShips$()\{$

$$ return shipRepository.findAll$()$;

$\}$

$/**$

$*$ @return ship entity by id

$*/$

$$ public Ship getShipById$($long id$)\{$

$$ return shipRepository.findById$($id$).$get$()$;

$\}$

$\}$