patternconverter.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_HELPER_PATTERN_CONVERTER_H
#define _LOG4CXX_HELPER_PATTERN_CONVERTER_H

#include <log4cxx/helpers/tchar.h>
#include <log4cxx/helpers/objectptr.h>
#include <log4cxx/helpers/objectimpl.h>

namespace log4cxx
{
	namespace spi
	{
		class LoggingEvent;
		typedef helpers::ObjectPtrT<LoggingEvent> LoggingEventPtr;
	} 

	namespace helpers
	{
		class FormattingInfo;

		class PatternConverter;
		typedef ObjectPtrT<PatternConverter> PatternConverterPtr;

		/**
		<p>PatternConverter is an abtract class that provides the
		formatting functionality that derived classes need.

		<p>Conversion specifiers in a conversion patterns are parsed to
		individual PatternConverters. Each of which is responsible for
		converting a logging event in a converter specific manner.
		*/
		class LOG4CXX_EXPORT PatternConverter : public ObjectImpl
		{
		public:
			DECLARE_ABSTRACT_LOG4CXX_OBJECT(PatternConverter)
			BEGIN_LOG4CXX_CAST_MAP()
				LOG4CXX_CAST_ENTRY(PatternConverter)
			END_LOG4CXX_CAST_MAP()

			PatternConverterPtr next;
			int minChar;
			int maxChar;
			bool leftAlign;
			mutable StringBuffer os;

		protected:
			PatternConverter();
			PatternConverter(const FormattingInfo& fi);

			/**
			Derived pattern converters must override this method in order to
			convert conversion specifiers in the correct way.
			*/
			virtual void convert(ostream& sbuf, 
				const spi::LoggingEventPtr& event) const = 0;

		public:
			/**
			A template method for formatting in a converter specific way.
			*/
			virtual void format(ostream& sbuf, const spi::LoggingEventPtr& e) const;

		}; // class PatternConverter
	}  // namespace helpers
}; // namespace log4cxx

#endif // _LOG4CXX_HELPER_PATTERN_CONVERTER_H