MemoryPersistence<T>

Inherits: IConfigurable, IReferenceable, IOpenable, ICleanable

Description

The MemoryPersistence class allows you to create persistence components that store data in memory.

Important points

• This is the most basic persistence component that is only able to store data items of any type.
• Specific CRUD operations over the data items must be implemented in child classes by accessing the this._items property and calling the Save method.
• The component supports loading and saving items from another data source. This allows to use it as a base class for file and other types of persistence components that cache all data in memory.

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 memory persistence component.

protected MemoryPersistence(ILoader loader, ISaver saver)

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

Creates a new instance of the persistence.

public MemoryPersistence()

Fields

Instance methods

Clear

Clears the component’s state.

public Task ClearAsync(string correlationId)

• correlationId: string - (optional) transaction id used to trace execution through the call chain.

Configure

Configures the component by passing its configuration parameters.

public virtual void Configure(ConfigParams config)

• config: ConfigParams - configuration parameters to be set.

Create

Creates a data item.

public virtual Task<T> CreateAsync(string correlationId, T item)

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

DeleteByFilter

Deletes data items that match to a given filter. This method shall be called by a public DeleteByFilter method from a child class that receives FilterParams and converts them into a filter function.

public Task DeleteByFilterAsync(string correlationId, IList<Func<T, bool>> matchFunctions)

• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• matchFunctions: IList<Func<T, bool>> - (optional) filter function used to filter items.

GetCountByFilter

Note: this method is not implemented yet

Gets the number of items retrieved by a given filter.

This method shall be called by a public GetCountByFilter method from a child class that receives FilterParams and converts them into a filter function.

protected GetCountByFilter(correlationId: string, filter: object): Task<int>

• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• filter: object - id of the item to be deleted
• returns: Task<int> - number of data items that satisfy the filter.

GetListByFilterAsync

Gets a list of data items retrieved by a given filter and sorted according to sorting parameters.

This method shall be called by a public GetListByFilterAsync method from a child class that receives FilterParams and converts them into a filter function.

public Task<List<T>> GetListByFilterAsync(string correlationId, IList<Func<T, bool>> matchFunctions)

• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• matchFunctions: IList<Func<T, bool>> - (optional) filter function used to filter items
• returns: Task<List<T>> - data list of filtered results.

GetOneRandomAsync

Gets a random item from items that match to a given filter.

This method shall be called by a public GetOneRandomAsync method from a child class that receives FilterParams and converts them into a filter function.

public Task<T> GetOneRandomAsync(string correlationId, IList<Func<T, bool>> matchFunctions)

• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• matchFunctions: IList<Func<T, bool>> - (optional) filter function to filter items.
• returns: Task<T> - random item.

GetPageByFilter

Gets a page of data items retrieved by a given filter and sorted according to sorting parameters.

This method shall be called by a public getPageByFilter method from a child class that receives FilterParams and converts them into a filter function.

public async Task<DataPage> GetPageByFilterAsync(string correlationId, IList<Func<T, bool>> matchFunctions, PagingParams paging)

• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• matchFunctions: IList<Func<T, bool>> - filter function used to filter items
• paging: PagingParams - (optional) paging parameters
• returns: Task<DataPage> - data page with filterd results.

IsOpen

Checks if the component is open.

public bool IsOpen()

• returns: bool - true if the component is open and false otherwise.

LoadAsync

Loads items.

private Task LoadAsync(string correlationId)

• correlationId: string - (optional) transaction id used to trace execution through the call chain.

OpenAsync

Opens the component.

public Task OpenAsync(string correlationId)

• correlationId: string - (optional) transaction id used to trace execution through the call chain.

SaveAsync

Saves items to an external data source using a configured saver component.

public Task SaveAsync(string correlationId)

• correlationId: string - (optional) transaction id used to trace execution through the call chain.

SetReferences

Sets the component’s references. References must match configured dependencies.

public void SetReferences(IReferences references)

• references: IReferences - references to set.

Examples

class MyMemoryPersistence extends MemoryPersistence<MyData>
{
    public MyData GetByName(String correlationId, String name)
    {
        MyData item = _items.Find((mydata) => { return mydata.Name == name; });
        ...
        return item;
    } 
    public MyData Set(String correlatonId, MyData item)
    {
        this._items = _items.Filter((mydata) => { return mydata.Name != name; });
        ...
        this._items.add(item);
        this.save(correlationId);
    }
    
var persistence = new MyMemoryPersistence();

persistence.Set("123", new MyData("ABC"));
Console.Out.WriteLine(persistence.getByName("123", "ABC")).toString(); // Result: { name: "ABC" }