xmllayout.h

功能非常强的写日志程序

/*
 * Copyright 2003,2004 The Apache Software Foundation.
 * 
 * Licensed 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.
 */
 
#ifndef _LOG4CXX_XML_LAYOUT_H
#define _LOG4CXX_XML_LAYOUT_H

#include <log4cxx/layout.h>

namespace log4cxx
{
	namespace xml
	{
		class XMLLayout;
		typedef helpers::ObjectPtrT<XMLLayout> XMLLayoutPtr;
	
		/**
		The output of the XMLLayout consists of a series of log4j:event
		elements as defined in the <a
		href="doc-files/log4j.dtd">log4j.dtd</a>. It does not output a
		 complete well-formed XML file. The output is designed to be
		included as an <em>external entity</em> in a separate file to form
		a correct XML file.
		
		<p>For example, if <code>abc</code> is the name of the file where
		the XMLLayout ouput goes, then a well-formed XML file would be:
		
		<code>
		<?xml version="1.0" ?>
		
		<!DOCTYPE log4j:eventSet SYSTEM "log4j.dtd" [<!ENTITY data SYSTEM "abc">]>
		
		<log4j:eventSet version="1.2" xmlns:log4j="http://jakarta.apache.org/log4j/">
		
			@&data;
			
		</log4j:eventSet>
		</code>
		
		<p>This approach enforces the independence of the XMLLayout and the
		appender where it is embedded.
		*/
		class LOG4CXX_EXPORT XMLLayout : public Layout
		{
		private:
			/**
			A string constant used in naming the option for setting the the
			location information flag.  Current value of this string
			constant is <b>LocationInfo</b>.
			*/
			static String LOCATION_INFO_OPTION;

			// Print no location info by default
			bool locationInfo; //= false

		public:
			DECLARE_LOG4CXX_OBJECT(XMLLayout)
			BEGIN_LOG4CXX_CAST_MAP()
				LOG4CXX_CAST_ENTRY(XMLLayout)
				LOG4CXX_CAST_ENTRY_CHAIN(Layout)
			END_LOG4CXX_CAST_MAP()

			XMLLayout();
			
			/**
			The <b>LocationInfo</b> option takes a boolean value. By
			default, it is set to false which means there will be no location
			information output by this layout. If the the option is set to
			true, then the file name and line number of the statement
			at the origin of the log statement will be output.

			<p>If you are embedding this layout within a SMTPAppender
			then make sure to set the
			<b>LocationInfo</b> option of that appender as well.
			*/
			inline void setLocationInfo(bool locationInfo)
				{ this->locationInfo = locationInfo; }

				/**
			Returns the current value of the <b>LocationInfo</b> option.
			*/
			inline bool getLocationInfo() const
				{ return locationInfo; }

			/** No options to activate. */
			void activateOptions() { }

			/**
			Set options
			*/
			virtual void setOption(const String& option,
				const String& value);

			/**
			* Formats a {@link spi::LoggingEvent LoggingEvent} 
			* in conformance with the log4cxx.dtd.
			**/
			virtual void format(ostream& output, const spi::LoggingEventPtr& event) const;

			/**
			The XMLLayout prints and does not ignore exceptions. Hence the
			return value <code>false</code>.
			*/
			virtual bool ignoresThrowable() const
				{ return false; }
				
		};  // class XMLLayout
	}  // namespace xml
}; // namespace log4cxx

#endif // _LOG4CXX_XML_LAYOUT_H