#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

using log4net.Util;

namespace log4net;

/// <summary>
/// The log4net Thread Context.
/// </summary>
/// <remarks>
/// <para>
/// The <see cref="ThreadContext"/> provides a location for thread specific debugging 
/// information to be stored.
/// The <see cref="ThreadContext"/> properties override any <see cref="GlobalContext"/>
/// properties with the same name.
/// </para>
/// <para>
/// The thread context has a properties map and a stack.
/// The properties and stack can 
/// be included in the output of log messages. The <see cref="Layout.PatternLayout"/>
/// supports selecting and outputting these properties.
/// </para>
/// <para>
/// The Thread Context provides a diagnostic context for the current thread. 
/// This is an instrument for distinguishing interleaved log
/// output from different sources. Log output is typically interleaved
/// when a server handles multiple clients near-simultaneously.
/// </para>
/// <para>
/// The Thread Context is managed on a per thread basis.
/// </para>
/// </remarks>
/// <example>Example of using the thread context properties to store a username.
/// <code lang="C#">
/// ThreadContext.Properties["user"] = userName;
///  log.Info("This log message has a ThreadContext Property called 'user'");
/// </code>
/// </example>
/// <example>Example of how to push a message into the context stack
/// <code lang="C#">
///  using(ThreadContext.Stacks["NDC"].Push("my context message"))
///  {
///    log.Info("This log message has a ThreadContext Stack message that includes 'my context message'");
///  
///  } // at the end of the using block the message is automatically popped 
/// </code>
/// </example>
/// <threadsafety static="true" instance="true" />
/// <author>Nicko Cadell</author>
public static class ThreadContext
{
  /// <summary>
  /// The thread properties map
  /// </summary>
  /// <value>
  /// The thread properties map
  /// </value>
  /// <remarks>
  /// <para>
  /// The <see cref="ThreadContext"/> properties override any <see cref="GlobalContext"/>
  /// properties with the same name.
  /// </para>
  /// </remarks>
  public static ThreadContextProperties Properties { get; } = new();

  /// <summary>
  /// The thread stacks
  /// </summary>
  /// <value>
  /// stack map
  /// </value>
  /// <remarks>
  /// <para>
  /// The thread local stacks.
  /// </para>
  /// </remarks>
  public static ThreadContextStacks Stacks { get; } = new(Properties);
}
