/*****************************************************************************
* Copyright (C) The Apache Software Foundation. All rights reserved. *
* ------------------------------------------------------------------------- *
* This software is published under the terms of the Apache Software License *
* version 1.1, a copy of which has been included with this distribution in *
* the LICENSE file. *
*****************************************************************************/
package org.apache.cocoon.util.log;
import org.apache.log.Hierarchy;
import org.apache.log.LogEvent;
import org.apache.log.Priority;
import org.apache.log.format.Formatter;
import java.io.StringWriter;
import java.util.Stack;
/**
* A refactoring of <code>org.apache.log.format.PatternFormatter</code> that
* can be extended.
* This formater formats the LogEntries according to a input pattern
* string.
*
* The format of each pattern element can be %[+|-]#.#{field:subformat}
*
* The +|- indicates left or right justify.
* The #.# indicates the minimum and maximum size of output.
* 'field' indicates which field is to be output and must be one of
* properties of LogEvent
* 'subformat' indicates a particular subformat and is currently unused.
*
* @author <a href="mailto:donaldp@apache.org">Peter Donald</a>
* @author <a href="mailto:sylvain@apache.org">Sylvain Wallez</a>
* @version CVS $Revision: 1.1 $ $Date: 2002/01/03 12:31:22 $
*/
public class ExtensiblePatternFormatter
implements Formatter
{
protected final static int TYPE_TEXT = 1;
protected final static int TYPE_CATEGORY = 2;
protected final static int TYPE_MESSAGE = 4;
protected final static int TYPE_TIME = 5;
protected final static int TYPE_RELATIVE_TIME = 6;
protected final static int TYPE_THROWABLE = 7;
protected final static int TYPE_PRIORITY = 8;
/**
* The maximum value used for TYPEs. Subclasses can define their own TYPEs
* starting at <code>MAX_TYPE + 1</code>.
*/
protected final static int MAX_TYPE = 8;
protected final static String TYPE_CATEGORY_STR = "category";
protected final static String TYPE_MESSAGE_STR = "message";
protected final static String TYPE_TIME_STR = "time";
protected final static String TYPE_RELATIVE_TIME_STR = "rtime";
protected final static String TYPE_THROWABLE_STR = "throwable";
protected final static String TYPE_PRIORITY_STR = "priority";
protected final static String SPACE_16 = " ";
protected final static String SPACE_8 = " ";
protected final static String SPACE_4 = " ";
protected final static String SPACE_2 = " ";
protected final static String SPACE_1 = " ";
protected final static String EOL = System.getProperty("line.separator", "\n");
protected static class PatternRun
{
public String m_data;
public boolean m_rightJustify;
public int m_minSize;
public int m_maxSize;
public int m_type;
public String m_format;
}
protected PatternRun m_formatSpecification[];
/**
* Extract and build a pattern from input string.
*
* @param stack the stack on which to place patterns
* @param pattern the input string
* @param index the start of pattern run
* @return the number of characters in pattern run
*/
protected int addPatternRun( final Stack stack,
final char pattern[],
int index )
{
final PatternRun run = new PatternRun();
final int start = index++;
//first check for a +|- sign
if( '+' == pattern[ index ] ) index++;
else if( '-' == pattern[ index ] )
{
run.m_rightJustify = true;
index++;
}
if( Character.isDigit( pattern[ index ] ))
{
int total = 0;
while( Character.isDigit( pattern[ index ] ) )
{
total = total * 10 + (pattern[ index ] - '0');
index++;
}
run.m_minSize = total;
}
//check for . sign indicating a maximum is to follow
if( index < pattern.length && '.' == pattern[ index ] )
{
index++;
if( Character.isDigit( pattern[ index ] ))
{
int total = 0;
while( Character.isDigit( pattern[ index ] ) )
{
total = total * 10 + (pattern[ index ] - '0');
index++;
}
run.m_maxSize = total;
}
}
if( index >= pattern.length || '{' != pattern[ index ] )
{
throw
new IllegalArgumentException( "Badly formed pattern at character " +
index );
}
int typeStart = index;
while( index < pattern.length &&
pattern[ index ]!= ':' && pattern[ index ] != '}' )
{
index++;
}
int typeEnd = index - 1;
final String type =
new String( pattern, typeStart + 1, typeEnd - typeStart );
run.m_type = getTypeIdFor( type );
if( index < pattern.length && pattern[ index ] == ':' )
{
index++;
while( index < pattern.length && pattern[ index ] != '}' ) index++;
final int length = index - typeEnd - 2;
if( 0 != length )
{
run.m_format = new String( pattern, typeEnd + 2, length );
}
}
if( index >= pattern.length || '}' != pattern[ index ] )
{
throw new
IllegalArgumentException("Unterminated type in pattern at character "
+ index );
}
index++;
stack.push( run );
return index - start;
}
/**
* Extract and build a text run from input string.
* It does special handling of '\n' and '\t' replaceing
* them with newline and tab.
*
* @param stack the stack on which to place runs
* @param pattern the input string
* @param index the start of the text run
* @return the number of characters in run
*/
protected int addTextRun( final Stack stack,
final char pattern[],
int index )
{
final PatternRun run = new PatternRun();
final int start = index;
boolean escapeMode = false;
if( '%' == pattern[ index ] ) index++;
final StringBuffer sb = new StringBuffer();
while( index < pattern.length && pattern[ index ] != '%' )
{
if( escapeMode )
{
if( 'n' == pattern[ index ] ) sb.append( EOL );
else if( 't' == pattern[ index ] ) sb.append( '\t' );
else sb.append( pattern[ index ] );
escapeMode = false;
}
else if( '\\' == pattern[ index ] ) escapeMode = true;
else sb.append( pattern[ index ] );
index++;
}
run.m_data = sb.toString();
run.m_type = TYPE_TEXT;
stack.push( run );
return index - start;
}
/**
* Utility to append a string to buffer given certain constraints.
*
* @param sb the StringBuffer
* @param minSize the minimum size of output (0 to ignore)
* @param maxSize the maximum size of output (0 to ignore)
* @param rightJustify true if the string is to be right justified in it's box.
* @param output the input string
*/
protected void append( final StringBuffer sb,
final int minSize,
final int maxSize,
final boolean rightJustify,
final String output )
{
final int size = output.length();
if( size < minSize )
{
//assert( minSize > 0 );
if( rightJustify )
{
appendWhiteSpace( sb, minSize - size );
sb.append( output );
}
else
{
sb.append( output );
appendWhiteSpace( sb, minSize - size );
}
}
else if( maxSize > 0 && maxSize < size )
{
if( rightJustify )
{
sb.append( output.substring( size - maxSize ) );
}
else
{
sb.append( output.substring( 0, maxSize ) );
}
}
else
{
sb.append( output );
}
}
/**
* Append a certain number of whitespace characters to a StringBuffer.
*
* @param sb the StringBuffer
* @param length the number of spaces to append
*/
protected void appendWhiteSpace( final StringBuffer sb, int length )
{
while( length >= 16 )
{
sb.append( SPACE_16 );
length -= 16;
}
if( length >= 8 )
{
sb.append( SPACE_8 );
length -= 8;
}
if( length >= 4 )
{
sb.append( SPACE_4 );
length -= 4;
}
if( length >= 2 )
{
sb.append( SPACE_2 );
length -= 2;
}
if( length >= 1 )
{
sb.append( SPACE_1 );
length -= 1;
}
}
/**
* Format the event according to the pattern.
*
* @param event the event
* @return the formatted output
*/
public String format( final LogEvent event )
{
final StringBuffer sb = new StringBuffer();
for( int i = 0; i < m_formatSpecification.length; i++ )
{
final PatternRun run = m_formatSpecification[ i ];
//treat text differently as it doesn't need min/max padding
if ( run.m_type == TYPE_TEXT )
{
sb.append( run.m_data );
}
else
{
final String data = formatPatternRun( event, run );
if( null != data )
{
append( sb, run.m_minSize, run.m_maxSize, run.m_rightJustify, data );
}
}
}
return sb.toString();
}
/**
* Formats a single pattern run (can be extended in subclasses).
*
* @param run the pattern run to format.
* @return the formatted result.
*/
protected String formatPatternRun( final LogEvent event, final PatternRun run )
{
String str = null;
switch( run.m_type )
{
case TYPE_RELATIVE_TIME:
str = getTime( event.getRelativeTime(), run.m_format );
break;
case TYPE_TIME:
str = getTime( event.getTime(), run.m_format );
break;
case TYPE_THROWABLE:
str = getStackTrace( event.getThrowable(), run.m_format );
break;
case TYPE_MESSAGE:
str = getMessage( event.getMessage(), run.m_format );
break;
case TYPE_CATEGORY:
str = getCategory( event.getCategory(), run.m_format );
break;
case TYPE_PRIORITY:
str = getPriority( event.getPriority(), run.m_format );
break;
default:
//TODO: Convert next line to use error handler
Hierarchy.getDefaultHierarchy().log( "Unknown Pattern specification." + run.m_type );
}
return str;
}
/**
* Utility method to format category.
*
* @param category the category string
* @param format ancilliary format parameter - allowed to be null
* @return the formatted string
*/
protected String getCategory( final String category, final String format )
{
return category;
}
/**
* Get formatted priority string.
*/
protected String getPriority( final Priority priority, final String format )
{
return priority.getName();
}
/**
* Correct a context string by replacing '.''s with a '_'.
*
* @param context the un-fixed context
* @return the fixed context
*/
protected final String fix( final String context )
{
return context.replace( '.', '_' );
}
/**
* Utility method to format message.
*
* @param message the message string
* @param format ancilliary format parameter - allowed to be null
* @return the formatted string
*/
protected String getMessage( final String message, final String format )
{
return message;
}
/**
* Utility method to format stack trace.
*
* @param throwable the throwable instance
* @param format ancilliary format parameter - allowed to be null
* @return the formatted string
*/
protected String getStackTrace( final Throwable throwable, final String format )
{
if( null == throwable ) return "";
final StringWriter sw = new StringWriter();
throwable.printStackTrace( new java.io.PrintWriter( sw ) );
return sw.toString();
}
/**
* Utility method to format time.
*
* @param time the time
* @param format ancilliary format parameter - allowed to be null
* @return the formatted string
*/
protected String getTime( final long time, final String format )
{
return Long.toString( time );
}
/**
* Retrieve the type-id for a particular string.
*
* @param type the string
* @return the type-id
*/
protected int getTypeIdFor( final String type )
{
if( type.equalsIgnoreCase( TYPE_CATEGORY_STR ) ) return TYPE_CATEGORY;
else if( type.equalsIgnoreCase( TYPE_MESSAGE_STR ) ) return TYPE_MESSAGE;
else if( type.equalsIgnoreCase( TYPE_PRIORITY_STR ) ) return TYPE_PRIORITY;
else if( type.equalsIgnoreCase( TYPE_TIME_STR ) ) return TYPE_TIME;
else if( type.equalsIgnoreCase( TYPE_RELATIVE_TIME_STR ) ) return TYPE_RELATIVE_TIME;
else if( type.equalsIgnoreCase( TYPE_THROWABLE_STR ) )
{
return TYPE_THROWABLE;
}
else
{
throw new IllegalArgumentException( "Unknown Type in pattern - " +
type );
}
}
/**
* Parse the input pattern and build internal data structures.
*
* @param patternString the pattern
*/
protected void parse( final String patternString )
{
final Stack stack = new Stack();
final int size = patternString.length();
final char pattern[] = new char[ size ];
int index = 0;
patternString.getChars( 0, size, pattern, 0 );
while( index < size )
{
if( pattern[ index ] == '%' &&
!( index != size - 1 && pattern[ index + 1 ] == '%' ) )
{
index += addPatternRun( stack, pattern, index );
}
else
{
index += addTextRun( stack, pattern, index );
}
}
final int elementCount = stack.size();
m_formatSpecification = new PatternRun[ elementCount ];
for( int i = 0; i < elementCount; i++ )
{
m_formatSpecification[ i ] = (PatternRun) stack.elementAt( i );
}
}
/**
* Set the string description that the format is extracted from.
*
* @param format the string format
*/
public void setFormat( final String format )
{
parse( format );
}
}