Behavioral Pattern - Mediator Pattern

Definition:

Mediator defines an object that encapsulates how a set of objects interact. Mediator promotes loose coupling by keeping objects from referring to each other explicitly, and it lets you vary their interaction independently.

UML Diagram:

Sample code:

Mediator:

public enum BillerType
    {
        Vodafone = 1,
        BESCOM = 2,
        TataIndicom = 3,
        Airtel = 4
    }
    public interface IBillPayAgent : IDisposable
    {
       
        bool PayBill(double amount);
    }
    public class BillPayAgent : IBillPayAgent
    {
        private BillerType _billerType;
        public BillPayAgent(BillerType billerType)
        {
            this._billerType = billerType;
        }
        private IBiller Biller
        {
            get { return BillerFactory.GetFactory(_billerType); }
        }
        public bool PayBill(double amount)
        {
            using (Biller)
            {
                Biller.ReceiveAmount(amount);
            }
            return true;
        }

        public void Dispose()
        {
            Dispose(true);
        }

        ~BillPayAgent()
        {
            Dispose(false);
        }

        protected virtual void Dispose(bool disposing)
        {
            if (disposing)
                GC.SuppressFinalize(this);
        }
    }

Supplier:

    public class IBiller : IDisposable
    {
        public virtual void ReceiveAmount(double amount)
        {
            Console.WriteLine("Received Amount: " + amount.ToString());
        }

        public void Dispose()
        {
            Dispose(true);
        }

        ~IBiller()
        {
            Dispose(false);
        }

        protected virtual void Dispose(bool disposing)
        {
            if (disposing)
                GC.SuppressFinalize(this);
        }
    }

    public sealed class Vodafone : IBiller
    {
        public override void ReceiveAmount(double amount)
        {
            Console.WriteLine("Greetings from Vodafone");
            base.ReceiveAmount(amount);
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing)
                GC.SuppressFinalize(this);
            base.Dispose(disposing);
        }
    }

    public sealed class TataIndicom : IBiller
    {
        public override void ReceiveAmount(double amount)
        {
            Console.WriteLine("Greetings from TataIndicom");
            base.ReceiveAmount(amount);
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing)
                GC.SuppressFinalize(this);
            base.Dispose(disposing);
        }
    }

    public sealed class BESCOM : IBiller
    {
        public override void ReceiveAmount(double amount)
        {
            Console.WriteLine("Greetings from BESCOM");
            base.ReceiveAmount(amount);
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing)
                GC.SuppressFinalize(this);
            base.Dispose(disposing);
        }
    }

    public sealed class Airtel : IBiller
    {
        public override void ReceiveAmount(double amount)
        {
            Console.WriteLine("Greetings from Airtel");
            base.ReceiveAmount(amount);
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing)
                GC.SuppressFinalize(this);
            base.Dispose(disposing);
        }
    }

Consumer:

public class Consumer : IDisposable
    {
        private IBillPayAgent billPayAgent = default(IBillPayAgent);
       
        public void DoShopping()
        {
            Console.WriteLine("I am doing shopping");
        }

        public void PayEBBill(double amount)
        {
            using (billPayAgent = new BillPayAgent(BillerType.BESCOM))
            {
                billPayAgent.PayBill(amount);
            }
        }

        public void PayMobileBill(double amount,BillerType billerType)
        {
            using (billPayAgent = new BillPayAgent(billerType))
            {
                billPayAgent.PayBill(amount);
            }
        }

        public void Dispose()
        {
            Dispose(true);
        }

        ~Consumer()
        {
            Dispose(false);
        }

        protected virtual void Dispose(bool disposing)
        {
            if (disposing)
                GC.SuppressFinalize(this);
        }
    }

Disposable pattern using IDisposable in C#

public interface ISomeInterface : IDisposable
    {
        void SomeMethod();
    }

    public class MyClass : ISomeInterface
    {
        public void SomeMethod()
        {
        }

        public void Dispose()
        {
            this.Dispose(true);
        }

        ~MyClass()
        {
            this.Dispose(false);
        }

        protected virtual void Dispose(bool disposing)
        {
            if (disposing)
                GC.SuppressFinalize(this);
        }
    }

Code to execute:

MyClass myClass = new MyClass();

            try
            {
                myClass.SomeMethod();
            }
            finally
            {
                myClass.Dispose();
                myClass = null;
            }

Please note that, if the object is of IDisposable; it is better to use using {....} block in C#. It internally takes care of the garbage collection.

Elements.xml file for creating folders inside document library

Below is the sample elements.xml file content for creating folders inside document library through features

<?xml version="1.0" encoding="utf-8" ?>
<Elements xmlns="http://schemas.microsoft.com/sharepoint/"><Module Path ="Client Supplies" Url ="Requirement/Client Supplies" />
<Module Path ="Functional Requirements" Url ="Requirement/Functional Requirements" />

</Elements>

Please note that, like this any level of nested folder structure can be created. (Url = "Docs/FirstLevel/SecondLevel/ThirdLevel"

Solution for "Cannot complete action. Try again later" error while activating ListInstance in sharepoint

Each ListInstance in ListInstance.xml file must contain "FeatureId="00bfea71-e717-4e80-aa17-d0c71b360101"" to avoid this error. 

Basically, your <ListInstance> node should look like as shown below;

    <ListInstance
           Title="Requirement Management"
           Description="Requirement Management"
           Id="A26D9F72-5F3B-477d-8E43-CB20698BC669"
           TemplateType="101"
FeatureId="00bfea71-e717-4e80-aa17-d0c71b360101"
OnQuickLaunch="true"
           Url="Requirement">
    </ListInstance>

The feature ID listed above is the FeatureID of the a normal (OOTB) sharepoint feature. This is required to find the TemplateType 101; which is a default doclib.