ChocolateBoiler_StaticInit.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace CreationalPatterns.Singleton
{
    public sealed class ChocolateBoiler_StaticInit
    {
        public bool Empty { get; set; }
        public bool Boiled { get; set; }

        // singleton instance
        private static readonly ChocolateBoiler_StaticInit instance = new ChocolateBoiler_StaticInit();

        private ChocolateBoiler_StaticInit()
        {
            this.Empty = true;
            this.Boiled = false;
        }

        public static ChocolateBoiler_StaticInit Instance
        {
            get
            {
                return instance;
            }
        }

        public void Fill()
        {
            // To fill the boiler, it must be empty, and once it's full, we set the empty and boiled flags
            if (this.Empty)
            {
                this.Empty = false;
                this.Boiled = false;

                // fill the boiler with a milk/chocolate mixture
            }
        }

        public void Drain()
        {
            // To drain the boiler, it must be full and also boiled.
            // Once it is drained we set the Empty property back to true
            if (!this.Empty && this.Boiled)
            {
                // drain the boiled milk and chocolate
                this.Empty = true;
            }
        }

        public void Boil()
        {
            // To boil the mixture, the boiler has to be full and not already boiled.
            // Once it is boiled we set the boiled flag to true
            if (!this.Empty && !this.Boiled)
            {
                // bring the contents to a boil
                this.Boiled = true;
            }
        }
    }
}