/Dependencies/log4net/Layout/XMLLayoutBase.cs

  1#region Apache License
  2//
  3// Licensed to the Apache Software Foundation (ASF) under one or more 
  4// contributor license agreements. See the NOTICE file distributed with
  5// this work for additional information regarding copyright ownership. 
  6// The ASF licenses this file to you under the Apache License, Version 2.0
  7// (the "License"); you may not use this file except in compliance with 
  8// the License. You may obtain a copy of the License at
  9//
 10// http://www.apache.org/licenses/LICENSE-2.0
 11//
 12// Unless required by applicable law or agreed to in writing, software
 13// distributed under the License is distributed on an "AS IS" BASIS,
 14// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 15// See the License for the specific language governing permissions and
 16// limitations under the License.
 17//
 18#endregion
 19
 20using System;
 21using System.IO;
 22using System.Text;
 23using System.Xml;
 24
 25using log4net.Util;
 26using log4net.Core;
 27
 28namespace log4net.Layout
 29{
 30	/// <summary>
 31	/// Layout that formats the log events as XML elements.
 32	/// </summary>
 33	/// <remarks>
 34	/// <para>
 35	/// This is an abstract class that must be subclassed by an implementation 
 36	/// to conform to a specific schema.
 37	/// </para>
 38	/// <para>
 39	/// Deriving classes must implement the <see cref="FormatXml"/> method.
 40	/// </para>
 41	/// </remarks>
 42	/// <author>Nicko Cadell</author>
 43	/// <author>Gert Driesen</author>
 44	abstract public class XmlLayoutBase : LayoutSkeleton
 45	{
 46		#region Protected Instance Constructors
 47
 48		/// <summary>
 49		/// Protected constructor to support subclasses
 50		/// </summary>
 51		/// <remarks>
 52		/// <para>
 53		/// Initializes a new instance of the <see cref="XmlLayoutBase" /> class
 54		/// with no location info.
 55		/// </para>
 56		/// </remarks>
 57		protected XmlLayoutBase() : this(false)
 58		{
 59			IgnoresException = false;
 60		}
 61
 62		/// <summary>
 63		/// Protected constructor to support subclasses
 64		/// </summary>
 65		/// <remarks>
 66		/// <para>
 67		/// The <paramref name="locationInfo" /> parameter determines whether 
 68		/// location information will be output by the layout. If 
 69		/// <paramref name="locationInfo" /> is set to <c>true</c>, then the 
 70		/// file name and line number of the statement at the origin of the log 
 71		/// statement will be output. 
 72		/// </para>
 73		/// <para>
 74		/// If you are embedding this layout within an SMTPAppender
 75		/// then make sure to set the <b>LocationInfo</b> option of that 
 76		/// appender as well.
 77		/// </para>
 78		/// </remarks>
 79		protected XmlLayoutBase(bool locationInfo)
 80		{
 81			IgnoresException = false;
 82			m_locationInfo = locationInfo;
 83		}
 84
 85		#endregion Protected Instance Constructors
 86
 87		#region Public Instance Properties
 88
 89		/// <summary>
 90		/// Gets a value indicating whether to include location information in 
 91		/// the XML events.
 92		/// </summary>
 93		/// <value>
 94		/// <c>true</c> if location information should be included in the XML 
 95		/// events; otherwise, <c>false</c>.
 96		/// </value>
 97		/// <remarks>
 98		/// <para>
 99		/// If <see cref="LocationInfo" /> is set to <c>true</c>, then the file 
100		/// name and line number of the statement at the origin of the log 
101		/// statement will be output. 
102		/// </para>
103		/// <para>
104		/// If you are embedding this layout within an <c>SMTPAppender</c>
105		/// then make sure to set the <b>LocationInfo</b> option of that 
106		/// appender as well.
107		/// </para>
108		/// </remarks>
109		public bool LocationInfo
110		{
111			get { return m_locationInfo; }
112			set { m_locationInfo = value; }
113		}
114		/// <summary>
115		/// The string to replace characters that can not be expressed in XML with.
116		/// <remarks>
117		/// <para>
118		/// Not all characters may be expressed in XML. This property contains the
119		/// string to replace those that can not with. This defaults to a ?. Set it
120		/// to the empty string to simply remove offending characters. For more
121		/// details on the allowed character ranges see http://www.w3.org/TR/REC-xml/#charsets
122		/// Character replacement will occur in  the log message, the property names 
123		/// and the property values.
124		/// </para>
125		/// </remarks>
126		/// </summary>
127		public string InvalidCharReplacement
128		{
129			get {return m_invalidCharReplacement;}
130			set {m_invalidCharReplacement=value;}
131		}
132		#endregion
133
134		#region Implementation of IOptionHandler
135
136		/// <summary>
137		/// Initialize layout options
138		/// </summary>
139		/// <remarks>
140		/// <para>
141		/// This is part of the <see cref="IOptionHandler"/> delayed object
142		/// activation scheme. The <see cref="ActivateOptions"/> method must 
143		/// be called on this object after the configuration properties have
144		/// been set. Until <see cref="ActivateOptions"/> is called this
145		/// object is in an undefined state and must not be used. 
146		/// </para>
147		/// <para>
148		/// If any of the configuration properties are modified then 
149		/// <see cref="ActivateOptions"/> must be called again.
150		/// </para>
151		/// </remarks>
152		override public void ActivateOptions() 
153		{
154			// nothing to do
155		}
156
157		#endregion Implementation of IOptionHandler
158
159		#region Override implementation of LayoutSkeleton
160
161		/// <summary>
162		/// Gets the content type output by this layout. 
163		/// </summary>
164		/// <value>
165		/// As this is the XML layout, the value is always <c>"text/xml"</c>.
166		/// </value>
167		/// <remarks>
168		/// <para>
169		/// As this is the XML layout, the value is always <c>"text/xml"</c>.
170		/// </para>
171		/// </remarks>
172		override public string ContentType
173		{
174			get { return "text/xml"; }
175		}
176
177		/// <summary>
178		/// Produces a formatted string.
179		/// </summary>
180		/// <param name="loggingEvent">The event being logged.</param>
181		/// <param name="writer">The TextWriter to write the formatted event to</param>
182		/// <remarks>
183		/// <para>
184		/// Format the <see cref="LoggingEvent"/> and write it to the <see cref="TextWriter"/>.
185		/// </para>
186		/// <para>
187		/// This method creates an <see cref="XmlTextWriter"/> that writes to the
188		/// <paramref name="writer"/>. The <see cref="XmlTextWriter"/> is passed 
189		/// to the <see cref="FormatXml"/> method. Subclasses should override the
190		/// <see cref="FormatXml"/> method rather than this method.
191		/// </para>
192		/// </remarks>
193		override public void Format(TextWriter writer, LoggingEvent loggingEvent) 
194		{
195			if (loggingEvent == null)
196			{
197				throw new ArgumentNullException("loggingEvent");
198			}
199
200			// Attach the protected writer to the TextWriter passed in
201			m_protectCloseTextWriter.Attach(writer);
202
203			XmlTextWriter xmlWriter = new XmlTextWriter(m_protectCloseTextWriter);
204			xmlWriter.Formatting = Formatting.None;
205			xmlWriter.Namespaces = false;
206
207			// Write the event to the writer
208			FormatXml(xmlWriter, loggingEvent);
209
210			xmlWriter.WriteWhitespace(SystemInfo.NewLine);
211
212			// Close on xmlWriter will ensure xml is flushed
213			// the protected writer will ignore the actual close
214			xmlWriter.Close();
215
216			// detach from the writer
217			m_protectCloseTextWriter.Attach(null);
218		}
219
220		#endregion Override implementation of LayoutSkeleton
221
222		#region Protected Instance Methods
223
224		/// <summary>
225		/// Does the actual writing of the XML.
226		/// </summary>
227		/// <param name="writer">The writer to use to output the event to.</param>
228		/// <param name="loggingEvent">The event to write.</param>
229		/// <remarks>
230		/// <para>
231		/// Subclasses should override this method to format
232		/// the <see cref="LoggingEvent"/> as XML.
233		/// </para>
234		/// </remarks>
235		abstract protected void FormatXml(XmlWriter writer, LoggingEvent loggingEvent);
236
237		#endregion Protected Instance Methods
238
239		#region Private Instance Fields
240  
241		/// <summary>
242		/// Flag to indicate if location information should be included in
243		/// the XML events.
244		/// </summary>
245		private bool m_locationInfo = false;
246
247		/// <summary>
248		/// Writer adapter that ignores Close
249		/// </summary>
250		private readonly ProtectCloseTextWriter m_protectCloseTextWriter = new ProtectCloseTextWriter(null);
251
252		/// <summary>
253		/// The string to replace invalid chars with
254		/// </summary>
255		private string m_invalidCharReplacement="?";
256
257		#endregion Private Instance Fields
258	}
259}