IdentifiableMemoryPersistence<T extends IIdentifiable<K>, K>

Extends: MemoryPersistence

Implements: IWriter, IGetter, ISetter

Description

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

Important points

• The data items must implement IIdentifiable.
• 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 this._items property and calling the save method on updates.

Configuration parameters

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 identifiable file persistence component.

public constructor(loader?: ILoader, saver?: ISaver)

• loader: ILoader - (optional) loader used to load items from an external datasource.
• saver: ISaver - (optional) saver used to save items to and external datasource.

Instance methods

create

Creates a data item.

public create(correlationId: string, item: T): Promise<T>

• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• item: T - item to be created.
• returns: Promise<T> - created item

deleteById

Deletes a data item based on it’s unique id.

public deleteById(correlationId: string, id: K): Promise<T>

• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• id: K - id of the item to be deleted
• returns: Promise<T> - deleted item.

deleteByIds

Deletes multiple data items based on their unique ids.

public deleteByIds(correlationId: string, ids: K[]): Promise<void>

• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• ids: K[] - ids of data items to be deleted.

getListByIds

Gets a list of data items retrieved by given unique ids.

public getListByIds(correlationId: string, ids: K[]): Promise<T[]>

• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• ids: K[] - ids of data items to be retrieved
• returns: Promise<T[]> - data list of results by ids.

getOneById

Gets a data item based on its unique id.

public getOneById(correlationId: string, id: K): Promise<T>

• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• id: K - id of data item to be retrieved.
• returns: Promise<T> - data item by id.

set

Sets a data item. If the data item exists, it updates it; otherwise, it creates a new data item.

public set(correlationId: string, item: T): Promise<T>

• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• item: T - item to be set.
• returns: Promise<T> - updated item

update

Updates a data item.

public update(correlationId: string, item: T): Promise<T>

• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• item: T - item to be updated.
• returns: Promise<T> - updated item.

updatePartially

Updates only a few selected fields in a data item.

public updatePartially(correlationId: string, id: K, data: AnyValueMap): Promise<T>

• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• id: K - id of a data item to be updated.
• data: AnyValueMap - map with fields to be updated.
• returns: Promise<T> - updated item.

Examples

class MyMemoryPersistence extends IdentifiableMemoryPersistence<MyData, string> {
  
    private composeFilter(filter: FilterParams): any {
        filter = filter || new FilterParams();
        let name = filter.getAsNullableString("name");
        return (item) => {
            if (name != null && item.name != name)
                return false;
            return true;
        };
    }
  
    public async getPageByFilter(correlationId: string, filter: FilterParams, paging: PagingParams): DataPage<MyData> {
        return await super.getPageByFilter(correlationId, this.composeFilter(filter), paging, null, null);
    }
  
}
let persistence = new MyMemoryPersistence();
     
let item = await persistence.create("123", { id: "1", name: "ABC" });
let page = await persistence.getPageByFilter(
        "123",
        FilterParams.fromTuples("name", "ABC"),
        null
 );
 console.log(page.data);          // Result: { id: "1", name: "ABC" }
     
 item = await persistence.deleteById("123", "1");

See also

• MemoryPersistence