IdentifiableFilePersistence<T, K>

Inherits: IdentifiableMemoryPersistence<T, K>

Description

The IdentifiableFilePersistence class allows you to create persistence components that store data in flat files and implement a number of CRUD operations over data items with unique ids.

Important points

• The data items must implement the IIdentifiable interface.
• In basic scenarios, child classes shall only override GetPageByFilter, GetListByFilter or DeleteByFilter operations with a specific filter function. All other operations can be used out of the box.
• In complex scenarios, child classes can implement additional operations by accessing cached items via the self._items property and calling the save method on updates.

Configuration parameters

• path: path to the file where data is stored

• options:

  • max_page_size: maximum number of items returned in a single page (default: 100)

References

• *:logger:*:*:1.0 - (optional) (../../../components/log/ilogger) components to pass log messages

Constructors

Creates a new instance of the persistence.

public IdentifiableFilePersistence(JsonFilePersister persister)

• persister: JsonFilePersister - (optional) persister component that loads and saves data from/to flat file.

Creates a new instance of the persistence.

public IdentifiableFilePersistence()

Fields

Instance methods

Configure

Configures a component by passing its configuration parameters.

public override void Configure(ConfigParams config)

• config: ConfigParams - configuration parameters to be set.

Examples

class MyFilePersistence: IdentifiableFilePersistence<MyData, string> 
{
    public MyFilePersistence(string path)
    {
        base(MyData.class, new JsonPersister(path));
        
    private List<Func<MyData, bool>> ComposeFilter(FilterParams filter)
    {
        filter = filter != null ? filter : new FilterParams();
        String name = filter.getAsNullableString("name");
        return List<Func<MyData, bool>>() {
        (item) => {
        if (name != null && item.name != name)
            return false;
        return true;
        }
        };
    }
    
    public DataPage<MyData> GetPageByFilter(string correlationId, FilterParams filter, PagingParams paging)
    {
        base.GetPageByFilter(correlationId, this.composeFilter(filter), paging, null, null);
    }
}

var persistence = new MyFilePersistence("./data/data.json");
var item = persistence.Create("123", new MyData("1", "ABC"));
var mydata = persistence.GetPageByFilter(
    "123",
    FilterParams.fromTuples("name", "ABC"),
null, null, null);
Console.Out.WriteLine(page.Data);          // Result: { id: "1", name: "ABC" }
persistence.DeleteById("123", "1");
...

See also

• MemoryPersistence