Pattern: Adapter

Adapter design pattern allows the interface of an existing class to be used as another interface.
It is often used to make existing classes work with others without modifying their source code.

Purpose of .NET implementation

You want to transfer data from a database Command to a DataTable.
The SQLiteDataAdapter serves as an adapter between the SQLiteCommand object (which represents a SQL command or stored procedure to execute against a SQLite database) and the DataTable object (which represents in-memory data in a tabular format).

Examples in .NET :

SQLiteDataAdapter

SQLiteDataAdapter example for Pattern Adapter

namespace Adaptor;
internal class SQLiteDataAdapterDemo
{
    /// <summary>
    ///Adaptee  - Command 
    ///Target  - DataTable
    ///Adapter  - SqlDataAdapter
    ///Target Method - Fill(Dataset instance)
    /// </summary>
    /// <returns></returns>
    public static async Task MainSqliteAdapterAsync()
    {
        //Target: Creates a DataTable instance to hold the data fetched from the database.
        var dataFormats = new DataTable();
        Console.WriteLine(dataFormats.Rows.Count);
        Console.WriteLine(dataFormats.Columns.Count);
        using (var con = new SQLiteConnection())
        {
            con.ConnectionString = "Data Source=CatalogRo.sqlite3";
            await con.OpenAsync();

            using (var cmd = new SQLiteCommand())
            {
                // Adaptee: Sets the SQL command text to fetch all records from the 'Format' table.
                cmd.CommandText = "select * from Format";
                cmd.Connection = con;
                using (var adapt = new SQLiteDataAdapter(cmd))
                {
                    // Adapter: Fills the DataTable (Target) with data fetched using the SQLiteCommand (Adaptee).
                    adapt.Fill(dataFormats);
                }
            }

        }
        Console.WriteLine(dataFormats.Rows.Count);
        Console.WriteLine(dataFormats.Columns.Count);
    }
}

EncodingAdapter

EncodingAdapter example for Pattern Adapter

namespace Adaptor;
internal class EncodingAdapterDemo
{
    /// <summary>
    ///Adaptee  - string 
    ///Target  - bytes
    ///Adapter  - encoding
    ///Target Method - GetBytes
    /// </summary>
    public static void AdapterStringByte()
    {
        var url = "http://msprogrammer.serviciipeweb.ro";
        Encoding e = new ASCIIEncoding();
        var b = e.GetBytes(url);

        Console.WriteLine($"from {e.EncodingName} number bytes {b.Length}");

        e = new UTF32Encoding();
        b = e.GetBytes(url);
        Console.WriteLine($"from {e.EncodingName} number bytes {b.Length}");

    }


}

Download source

See Source Code for Microsoft implementation of Adapter

SourceCode AsciiEncoding
SourceCode SqliteDataAdapter
SourceCode UTF32Encoding

Learn More

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Homework

iPhone 7 does not have a headphone jack.
Implement an adapter that will allow you to use your old headphones , that have jack, with the iPhone 7.