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 * may not use this file except in compliance with the License. You can obtain
 * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
 * or glassfish/bootstrap/legal/LICENSE.txt.  See the License for the specific
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 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
 * Sun designates this particular file as subject to the "Classpath" exception
 * as provided by Sun in the GPL Version 2 section of the License file that
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/*
 * BackupFilenameManager.java
 *
 * Created on August 13, 2004, 12:10 PM
 */

package com.sun.enterprise.config.backup;

import java.io.*;

/**
 * Manage filenames to select for backups.
 * @author bnevins
 */
class BackupFilenameManager
{
	BackupFilenameManager(File backupDir) throws BackupException
	{
		this.dir = backupDir;
		findZips();
		findLatest();
	}
	
	///////////////////////////////////////////////////////////////////////////

	File next() throws BackupException
	{
		int newVersionNum = 1;
		
		if(latestVersion != null)
			newVersionNum = latestVersion.num + 1;
	
		String suffix = padWithLeadingZeroes(newVersionNum);
		return new File(dir, Constants.BACKUP_FILENAME_ROOT + suffix + ".zip");
	}
	
	///////////////////////////////////////////////////////////////////////////

	File latest() throws BackupWarningException
	{
		if(latestVersion == null)
			throw new BackupWarningException("backup-res.NoBackupFiles", dir);
		
		return latestVersion.zip;
	}
	
	///////////////////////////////////////////////////////////////////////////////

	/** Looks through the backups directory and assembles
	 * a list of all backup files found.
	 * @throws BackupWarningException if there are no backup zip files
	 */	
	private void findZips() throws BackupWarningException
	{
		File[] zips = dir.listFiles(new ZipFilenameFilter());
		int len = 0;
		
		if(zips != null)
			len = zips.length;
		
		zipsAndNumbers = new ZipFileAndNumber[len];
		
		for(int i = 0; i < len; i++)
		{
			zipsAndNumbers[i] = new ZipFileAndNumber(zips[i]);
		}
	}
	
	///////////////////////////////////////////////////////////////////////////////

	/** Looks through the list of zips and sets the one with the biggest version number
	 */	
	private void findLatest() throws BackupWarningException
	{
		int biggest = 0;
		
		for(int i = 0; i < zipsAndNumbers.length; i++)
		{
			int curr = zipsAndNumbers[i].num;
			
			if(curr > biggest)
			{
				biggest = curr;
				latestVersion = zipsAndNumbers[i];
				LoggerHelper.fine(zipsAndNumbers[i].zip.toString() + " newest backup so far...");
			}
		}
	}
	
	///////////////////////////////////////////////////////////////////////////////

	/** Convert the array of zip filenames into an array of the number suffixes.
	 */	
	private String padWithLeadingZeroes(int num) throws BackupException
	{
		if(num < 10)
			return "0000" + num;

		if(num < 100)
			return "000" + num;
		
		if(num < 1000)
			return "00" + num;
		
		if(num < 10000)
			return "0" + num;

		if(num < 100000)
			return "" + num;
		
		throw new BackupException("Latest version >= 100,000.  Delete some backup files.");
	}
	
	///////////////////////////////////////////////////////////////////////////

	private static class ZipFileAndNumber
	{
		private ZipFileAndNumber(File zip)
		{
			this.zip = zip;
			String fname = zip.getName();
			
			if(isValid())
			{
				
				fname = fname.substring(Constants.BACKUP_FILENAME_ROOT.length(), fname.length() - 4);
				try
				{
					num = Integer.parseInt(fname);
				}
				catch(Exception e)
				{
					// nothing to do -- num is already set to -1
				}
			}
		}
		
		/**
		 * make sure that:
		 * (1) the filename is the right format
		 * (2) that it is internally correct (has a status file with a timestamp
		 **/
		
		private boolean isValid()
		{
			Status status = new Status();
			long time = status.getInternalTimestamp(zip);
			
			return time > 0 && zip.getName().startsWith(Constants.BACKUP_FILENAME_ROOT);
		}
		
		private File	zip;
		private int		num = -1;
	}

	///////////////////////////////////////////////////////////////////////////

	private File				dir;
	private	ZipFileAndNumber[]	zipsAndNumbers;
	private	int[]				numbers;
	private ZipFileAndNumber	latestVersion;
	
	///////////////////////////////////////////////////////////////////////////////


	public static void main(String[] args)
	{
		try
		{
			File f = new File("c:/tmp/test");
			BackupFilenameManager mgr = new BackupFilenameManager(f);
			File fnew = mgr.next();
			System.out.println("Next backup file: " + fnew);
			File fold = mgr.latest();
			System.out.println("Latest backup file: " + fold);
		}
		catch(Exception e)
		{
			e.printStackTrace();
		}
	}
}