90 lines
2.5 KiB
Go
90 lines
2.5 KiB
Go
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package data
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import (
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"encoding/json"
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"errors"
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"strconv"
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)
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type IRepository[T IIdentifiable] interface {
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/* An interface to manage generic structure objects persistently. Should
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* use an IDatastore as the interface that actually stores and retrieves the
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* data from an external source. */
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Create(t T) error
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Update(t T) error
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Delete(t T) error
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GetAll() ([]T, error)
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GetById(id uint) (T, error)
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GetByCriteria(c ISearchCriteria[T]) ([]T, error)
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}
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// --- default implementation ---
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type DefaultRepository[T IIdentifiable] struct {
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ds IDatastore
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prefix string
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}
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func NewDefaultRepository[T IIdentifiable](ds IDatastore, prefix string) *DefaultRepository[T] {
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return &DefaultRepository[T]{ ds: ds, prefix: prefix }
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}
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func (repo *DefaultRepository[T]) Create(t T) error {
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/* Creates a new entry in the repository with the given object t. Throws an
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* error if there already exists an entry with the same id, the json
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* encoding fails or the connection to the IDatastore fails. */
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key := repo.prefix + ":" + strconv.FormatUint(uint64(t.Id()), 10)
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exists, err := repo.ds.KeyExists(key)
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if err != nil { return err }
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if exists { return errors.New("key already exits") }
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d, err := json.Marshal(t)
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if err != nil { return err }
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err = repo.ds.Set(key, string(d))
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if err != nil { return err }
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return nil
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}
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func (repo *DefaultRepository[T]) Update(t T) error {
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/* Updates the entry with the same id as t in the repository with the
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* values of t. Trows an error if the json encoding fails or the connection
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* to the IDatastore fails. */
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key := repo.prefix + ":" + strconv.FormatUint(uint64(t.Id()), 10)
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exists, err := repo.ds.KeyExists(key)
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if err != nil { return err }
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if !exists { return errors.New("key does not exits") }
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d, err := json.Marshal(t)
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if err != nil { return err }
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err = repo.ds.Set(key, string(d))
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if err != nil { return err }
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return nil
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}
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func (repo *DefaultRepository[T]) Delete(t T) error {
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// TODO
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return nil
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}
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func (repo *DefaultRepository[T]) GetAll() ([]T, error) {
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// TODO
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return nil, nil
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}
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func (repo *DefaultRepository[T]) GetById(id uint) (T, error) {
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// TODO
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return *new(T), nil
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}
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func (repo *DefaultRepository[T]) GetByCriteria(c ISearchCriteria[T]) ([]T, error) {
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// TODO
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return nil, nil
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}
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