An Extension to the Enterprise Library Logging Application Block

//===============================================================================
// Microsoft patterns & practices Enterprise Library
// Logging Application Block
//===============================================================================
// Copyright � Microsoft Corporation.  All rights reserved.
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT
// LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
// FITNESS FOR A PARTICULAR PURPOSE.
//===============================================================================

using System.Configuration;
using Microsoft.Practices.EnterpriseLibrary.Common.Configuration;
using Microsoft.Practices.EnterpriseLibrary.Common.Configuration.ObjectBuilder;
using Microsoft.Practices.EnterpriseLibrary.Logging.Filters;
using Microsoft.Practices.EnterpriseLibrary.Logging.Properties;
using Microsoft.Practices.ObjectBuilder;

namespace Microsoft.Practices.EnterpriseLibrary.Logging.Configuration
{
	/// <summary>
	/// Represents the configuration for a priority filter.
	/// </summary>    
	[Assembler(typeof(PriorityFilterAssembler))]
	public class PriorityFilterData : LogFilterData
	{
		private const string minimumPriorityProperty = "minimumPriority";
		private const string maximumPriorityProperty = "maximumPriority";

		/// <summary>
		/// Initializes a new <see cref="PriorityFilterData"/>.
		/// </summary>
		public PriorityFilterData()
		{
		}

		/// <summary>
		/// Initializes a new <see cref="PriorityFilterData"/> with a minimum priority.
		/// </summary>
		/// <param name="minimumPriority">The minimum priority.</param>
		public PriorityFilterData(int minimumPriority)
			: this("priority", minimumPriority)
		{
		}

		/// <summary>
		/// Initializes a new named <see cref="PriorityFilterData"/> with a minimum priority.
		/// </summary>
		/// <param name="name">The name.</param>
		/// <param name="minimumPriority">The minimum priority.</param>
		public PriorityFilterData(string name, int minimumPriority)
			: base(name, typeof(PriorityFilter))
		{
			this.MinimumPriority = minimumPriority;
		}

		/// <summary>
		/// Gets or sets the minimum value for messages to be processed.  Messages with a priority
		/// below the minimum are dropped immediately on the client.
		/// </summary>
		[ConfigurationProperty(minimumPriorityProperty)]
		public int MinimumPriority
		{
			get
			{
				return (int)this[minimumPriorityProperty];
			}
			set
			{
				this[minimumPriorityProperty] = value;
			}
		}

		/// <summary>
		/// Gets or sets the maximum priority value for messages to be processed.  Messages with a priority
		/// above the maximum are dropped immediately on the client.
		/// </summary>		
		[ConfigurationProperty(maximumPriorityProperty, DefaultValue = int.MaxValue)]
		public int MaximumPriority
		{
			get
			{
				return (int)this[maximumPriorityProperty];
			}
			set
			{
				this[maximumPriorityProperty] = value;
			}
		}
	}

	/// <summary>
	/// This type supports the Enterprise Library infrastructure and is not intended to be used directly from your code.
	/// Represents the process to build a <see cref="PriorityFilter"/> described by a <see cref="PriorityFilterData"/> configuration object.
	/// </summary>
	/// <remarks>This type is linked to the <see cref="PriorityFilterData"/> type and it is used by the <see cref="LogFilterCustomFactory"/> 
	/// to build the specific <see cref="ILogFilter"/> object represented by the configuration object.
	/// </remarks>
	public class PriorityFilterAssembler : IAssembler<ILogFilter, LogFilterData>
	{
		/// <summary>
		/// This method supports the Enterprise Library infrastructure and is not intended to be used directly from your code.
		/// Builds a <see cref="PriorityFilter"/> based on an instance of <see cref="PriorityFilterData"/>.
		/// </summary>
		/// <seealso cref="LogFilterCustomFactory"/>
		/// <param name="context">The <see cref="IBuilderContext"/> that represents the current building process.</param>
		/// <param name="objectConfiguration">The configuration object that describes the object to build. Must be an instance of <see cref="PriorityFilterData"/>.</param>
		/// <param name="configurationSource">The source for configuration objects.</param>
		/// <param name="reflectionCache">The cache to use retrieving reflection information.</param>
		/// <returns>A fully initialized instance of <see cref="PriorityFilter"/>.</returns>
		public ILogFilter Assemble(IBuilderContext context, LogFilterData objectConfiguration, IConfigurationSource configurationSource, ConfigurationReflectionCache reflectionCache)
		{
			PriorityFilterData castedObjectConfiguration = (PriorityFilterData)objectConfiguration;

			ILogFilter createdObject
				= new PriorityFilter(
					castedObjectConfiguration.Name,
					castedObjectConfiguration.MinimumPriority,
					castedObjectConfiguration.MaximumPriority);

			return createdObject;
		}
	}
}