Daily Folder Appender

/*------------------------------------------------------------------------------
 * PACKAGE: com.freeware.log4j
 * FILE   : DailyFolderApender.java
 * CREATED: Jun 16, 2004
 * AUTHOR : Prasad P. Khandekar
 *------------------------------------------------------------------------------
 * Change Log:
 *-----------------------------------------------------------------------------*/
package com.freeware.log4j;

import java.io.File;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

import org.apache.log4j.FileAppender;
import org.apache.log4j.Layout;
import org.apache.log4j.helpers.LogLog;
import org.apache.log4j.spi.LoggingEvent;

/**
 * This DailyFolderAppender class extends {@link FileAppender} to facilitate creation
 * of folders on per day basis.
 * 
 * <p>The appender computes the proper filename using the format specified in  
 * <a href="http://java.sun.com/j2se/1.3/docs/api/java/text/SimpleDateFormat.html">
 * java.text.SimpleDateFormat</a>.
 * 
 * <p>Do not use the colon ":" and backslash "\" character(s) anywhere in the 
 * <b>DatePattern</b> option.
 *
 * <p><b>Parameters:</b>
 * <ol>
 * 		<li>DatePattern - The date pattern string.</li>
 * 		<li>RootFolder  - The root folder where the daily folders will be created.</li>
 * 		<li>FileName    - The name of the file. Needed only if you want to use the fixed file name.</li>
 * </ol>
 * <br>
 * @author <a HREF="mailto:KPrasadKhan@hotmail.com">Prasad P. Khandekar</a>
 * @version 1.0
 * @since 1.0
 */
public class DailyFolderAppender extends FileAppender
{
	/**
	 * The fixed date pattern to be used if one is not specified.
	 */
	private static String DATE_PATTERN = "yyyy-MM-dd";

	/**
	 * The folder under which daily folders are created. This can be a absolute path
	 * or relative path also.
	 * e.g. JavaLogs/CPRILog or F:/LogFiles/CPRILog
	 */
	private String mstrRootFolder;

	/**
	 * Used internally and contains the name of the daily folder derived from
	 * current system date. 
	 */
	private String mstrDateFolder;

	/**
	 * Holds the user specified DatePattern,
	 */
	private String mstrDatePattern = DATE_PATTERN;

	/**
	 * Holds the user specified file name. This allows fixed file names to be used
	 * as folders are created on daily basis. If not specified then file name is
	 * set to DailyFolder name.
	 */
	private String mstrFileName;

	/**
	 * The date formatter object used for parsing the user specified DatePattern.
	 */
	private SimpleDateFormat mobjSDF;

	/**
	 * Default constructor. This is required as the appender class is dynamically
	 * loaded.
	 */
	public DailyFolderAppender()
	{
	}

	public DailyFolderAppender(Layout pobjLayout, String pstrFolder, 
								String pstrPattern, String pstrFile) throws IOException
	{
		this.mstrRootFolder = createFolder(pstrFolder);
		this.mstrFileName = pstrFile;
		this.layout = pobjLayout;
		this.mstrDatePattern = checkPattern(pstrPattern);
		this.mstrDateFolder = this.mobjSDF.format(new Date(System.currentTimeMillis()));
		createFolder(pstrFolder + "\\" + this.mstrDateFolder);

		if (pstrFile != null)
			fileName = this.mstrRootFolder + "\\" + this.mstrDateFolder + 
						"\\" + pstrFile;
		else
			fileName = this.mstrRootFolder + "\\" + this.mstrDateFolder + 
						"\\" + this.mstrDateFolder + ".log";
		activateOptions();
	}

	/* (non-Javadoc)
	 * @see org.apache.log4j.FileAppender#activateOptions()
	 */
	public void activateOptions()
	{
		createFolder(this.mstrRootFolder + "\\" + this.mstrDateFolder);

		if (this.mstrFileName != null)
			fileName = this.mstrRootFolder + "\\" + this.mstrDateFolder + 
						"\\" + this.mstrDateFolder + ".log";
		else
			fileName = this.mstrRootFolder + "\\" + this.mstrDateFolder + 
							"\\" + this.mstrFileName;
		super.activateOptions();
	}

/*------------------------------------------------------------------------------
 * Getters
 *----------------------------------------------------------------------------*/
	public String getDatePattern()
	{
		return this.mstrDatePattern;
	}

	public String getRootFolder()
	{
		return this.mstrRootFolder;
	}

	public String getFileName()
	{
		return this.mstrFileName;
	}

/*------------------------------------------------------------------------------
 * Setters
 *----------------------------------------------------------------------------*/
	public void setDatePattern(String pstrPattern)
	{
		this.mstrDatePattern = checkPattern(pstrPattern);
		// derive the DateFolder name.
		this.mstrDateFolder = this.mobjSDF.format(new Date(System.currentTimeMillis()));
	}

	public void setRootFolder(String pstrFolder)
	{
		this.mstrRootFolder = createFolder(pstrFolder);
	}

	public void setFileName(String pstrFile)
	{
		this.mstrFileName = pstrFile;
	}

/*------------------------------------------------------------------------------
 * Methods
 *----------------------------------------------------------------------------*/
	/* (non-Javadoc)
	 * @see org.apache.log4j.WriterAppender#subAppend(org.apache.log4j.spi.LoggingEvent)
	 */
	protected void subAppend(LoggingEvent pobjEvent)
	{
		Date   dtNow;
		String strFolder;

		dtNow = new Date(System.currentTimeMillis());
		strFolder = this.mobjSDF.format(dtNow);
		if (!strFolder.equals(this.mstrDateFolder))
		{
			try
			{
				rollOver(strFolder);
				this.mstrDateFolder = strFolder;
			}
			catch (IOException IOEx)
			{
				LogLog.error("rollOver() failed!", IOEx);
			}
		}
		super.subAppend(pobjEvent);
	}

/*------------------------------------------------------------------------------
 * Helpers
 *----------------------------------------------------------------------------*/
	/**
	 * The helper function to vaildate the DatePattern.
	 * @param pstrPattern The DatePattern to be validated.
	 * @return The validated date pattern or defautlt DATE_PATTERN
	 */
	private String checkPattern(String pstrPattern)
	{
		String strRet = null;
		SimpleDateFormat objFmt = new SimpleDateFormat(DATE_PATTERN);

		try
		{
			this.mobjSDF = new SimpleDateFormat(pstrPattern);
			strRet = pstrPattern;
		}
		catch (NullPointerException NPExIgnore)
		{
			LogLog.error("Invalid DatePattern " + pstrPattern, NPExIgnore);
			this.mobjSDF = objFmt;
			strRet = DATE_PATTERN;
		}
		catch (IllegalArgumentException IlArgExIgnore)
		{
			LogLog.error("Invalid DatePattern " + pstrPattern, IlArgExIgnore);
			this.mobjSDF = objFmt;
			strRet = DATE_PATTERN;
		}
		finally
		{
			objFmt = null;
		}
		return strRet;
	}

	/**
	 * Helper function to create the folder(s) in a given path. 
	 * @param pstrPath The path to be used for folder creation.
	 * @return The folder path with last "\" or "/" removed.
	 */
	private String createFolder(String pstrPath)
	{
		char chrEnd;
		File objFile;

		pstrPath.trim();
		chrEnd = pstrPath.charAt(pstrPath.length() - 1);
		if (chrEnd == '\\' || chrEnd == '/')
			pstrPath = pstrPath.substring(0, (pstrPath.length() - 1));
	
		objFile = new File(pstrPath);
		// Ask file object to create all missing folders.
		objFile.mkdirs();
		objFile = null;
		return pstrPath;
	}

	/**
	 * This function is responsible for performing the actual file rollover.
	 * @param pstrName The name of the new folder based on current system date.
	 * @throws IOException
	 */
	private void rollOver(String pstrName) throws IOException
	{
		String strTemp;

		if (pstrName.equals(this.mstrDateFolder)) return;
		this.closeFile();

		createFolder(this.mstrRootFolder + "\\" + pstrName);
		if (this.mstrFileName != null)
			strTemp = this.mstrRootFolder + "\\" + pstrName + "\\" + pstrName + ".log";
		else
			strTemp = this.mstrRootFolder + "\\" + pstrName + "\\" + this.mstrFileName;
		this.setFile(strTemp, false, this.bufferedIO, this.bufferSize);
	}
}