Design Pattern Framework 4.0 C# 之三 Bridge

using System;
using System.Collections.Generic;

namespace DoFactory.GangOfFour.Bridge.NETOptimized
{
/// <summary>
/// MainApp startup class for .NET optimized
/// Bridge Design Pattern.
/// </summary>
class MainApp
{
/// <summary>
/// Entry point into console application.
/// </summary>
static void Main()
{
// Create RefinedAbstraction
Customers customers = new Customers { Group = "Chicago" };

// Set ConcreteImplementor
customers.DataObject = new CustomersData();

// Exercise the bridge
customers.Show();
customers.Next();
customers.Show();
customers.Next();
customers.Show();

customers.Add("Henry Velasquez");
customers.ShowAll();

// Wait for user
Console.ReadKey();
}
}

/// <summary>
/// The 'Abstraction' class
/// </summary>
class CustomersBase
{
// Gets or sets customer group
public string Group { get; set; }

// Gets or sets data object
public IDataObject DataObject { get; set; }

public virtual void Next()
{
DataObject.NextRecord();
}

public virtual void Prior()
{
DataObject.PriorRecord();
}

public virtual void Add(string name)
{
DataObject.AddRecord(name);
}

public virtual void Delete(string name)
{
DataObject.DeleteRecord(name);
}

public virtual void Show()
{
DataObject.ShowRecord();
}

public virtual void ShowAll()
{
Console.WriteLine("Customer Group: " + Group);
DataObject.ShowAllRecords();
}
}

/// <summary>
/// The 'RefinedAbstraction' class
/// </summary>
class Customers : CustomersBase
{
public override void ShowAll()
{
// Add separator lines
Console.WriteLine();
Console.WriteLine("------------------------");
base.ShowAll();
Console.WriteLine("------------------------");
}
}

/// <summary>
/// The 'Implementor' interface
/// </summary>
interface IDataObject
{
void NextRecord();
void PriorRecord();
void AddRecord(string name);
void DeleteRecord(string name);
void ShowRecord();
void ShowAllRecords();
}

/// <summary>
/// The 'ConcreteImplementor' class
/// </summary>
class CustomersData : IDataObject
{
private List<string> _customers;
private int _current = 0;

// Constructor
public CustomersData()
{
// Simulate loading from database
_customers = new List<string>
{ "Jim Jones", "Samual Jackson", "Allan Good",
"Ann Stills", "Lisa Giolani" };
}

public void NextRecord()
{
if (_current <= _customers.Count - 1)
{
_current++;
}
}

public void PriorRecord()
{
if (_current > 0)
{
_current--;
}
}

public void AddRecord(string customer)
{
_customers.Add(customer);
}

public void DeleteRecord(string customer)
{
_customers.Remove(customer);
}

public void ShowRecord()
{
Console.WriteLine(_customers[_current]);
}

public void ShowAllRecords()
{
_customers.ForEach(customer =>
Console.WriteLine(" " + customer));
}
}
}