AppSettingsParser

using System;
using System.Configuration;
using System.Diagnostics;

namespace BA.Core.Configuration {
    public sealed class AppSettingsParser {
        public static T Parse<T>(string settingName) {
            return Parse<T>(settingName,default(T),false,false,false);
        }
        public static T Parse<T>(string settingName,T defaultValue) {
            return Parse<T>(settingName,defaultValue,false,false,false);
        }
        public static T Parse<T>(string settingName,T defaultValue,bool logError) {
            return Parse<T>(settingName,defaultValue,logError,false,false);
        }
        public static T Parse<T>(string settingName,T defaultValue,bool logError,bool throwError) {
            return Parse<T>(settingName,defaultValue,logError,throwError,false);
        }
        public static T ParseEnum<T>(string settingName) {
            return Parse<T>(settingName,default(T),false,false,true);
        }
        public static T ParseEnum<T>(string settingName,T defaultValue) {
            return Parse<T>(settingName,defaultValue,false,false,true);
        }
        public static T ParseEnum<T>(string settingName,T defaultValue,bool logError) {
            return Parse<T>(settingName,defaultValue,logError,false,true);
        }
        public static T ParseEnum<T>(string settingName,T defaultValue,bool logError,bool throwError) {
            return Parse<T>(settingName,defaultValue,logError,throwError,true);
        }
        private static T Parse<T>(string settingName,T defaultValue,bool logError,bool throwError,bool isEnum) {
            T parsedValue = default(T);
            string settingValue = ConfigurationManager.AppSettings[settingName];
            try {
                if(settingValue != null) {
                    if(isEnum) {
                        parsedValue = (T)Enum.Parse(typeof(T),settingValue);
                    }
                    else
                        parsedValue = (T)Convert.ChangeType(settingValue,typeof(T));
                }
                else {
                    if(throwError)
                        throw new ArgumentNullException(settingName,"The AppSettings value is missing for " + settingName);

                    if(logError) {
                        EventLog.WriteEntry("AppSettingsHelper","The AppSettings value is missing for " + settingName,EventLogEntryType.Warning);
                    }
                    return defaultValue;
                }
            }
            catch(Exception error) {
                parsedValue = defaultValue;
                if(logError) {
                    if(!string.IsNullOrEmpty(settingValue))
                        EventLog.WriteEntry("AppSettingsHelper","The AppSettings value is an invalid " + typeof(T).Name + " and could not be parsed. " + settingName + " - " + settingValue + " ERROR: " + error.Message,EventLogEntryType.Warning);
                    else
                        EventLog.WriteEntry("AppSettingsHelper","The AppSettings value is missing for " + settingName + " ERROR: " + error.Message,EventLogEntryType.Warning);
                }
                if(throwError)
                    throw;
            }
            return parsedValue;
        }
    }
}