#region Apache License
//
// Licensed to the Apache Software Foundation (ASF) under one or more 
// contributor license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright ownership. 
// The ASF licenses this file to you under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance with 
// the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#endregion

// .NET Compact Framework 1.0 has no support for ASP.NET
// SSCLI 1.0 has no support for ASP.NET
#if !NETCF && !SSCLI && !CLIENT_PROFILE

using System.IO;
using System.Web;
using Ctrip.Log4.Core;
using Ctrip.Log4.Util;

namespace Ctrip.Log4.Layout.Pattern
{
	/// <summary>
	/// Abstract class that provides access to the current HttpContext (<see cref="HttpContext.Current" />) that 
	/// derived classes need.
	/// </summary>
	/// <remarks>
	/// This class handles the case when HttpContext.Current is null by writing
	/// <see cref="SystemInfo.NotAvailableText" /> to the writer.
	/// </remarks>
	/// <author>Ron Grabowski</author>
	internal abstract class AspNetPatternLayoutConverter : PatternLayoutConverter
	{
		protected override void Convert(TextWriter writer, LoggingEvent loggingEvent)
		{
			if (HttpContext.Current == null)
			{
				writer.Write(SystemInfo.NotAvailableText);
			}
			else
			{
				Convert(writer, loggingEvent, HttpContext.Current);
			}
		}

		/// <summary>
		/// Derived pattern converters must override this method in order to
		/// convert conversion specifiers in the correct way.
		/// </summary>
		/// <param name="writer"><see cref="TextWriter" /> that will receive the formatted result.</param>
		/// <param name="loggingEvent">The <see cref="LoggingEvent" /> on which the pattern converter should be executed.</param>
		/// <param name="httpContext">The <see cref="HttpContext" /> under which the ASP.Net request is running.</param>
		protected abstract void Convert(TextWriter writer, LoggingEvent loggingEvent, HttpContext httpContext);
	}
}

#endif