Ugluk/Persistence

 /**
  * Stores and retrieves data from the local cache.
  * Data may be targeting or movement statistics, debug information, etc.
  * 
  * @author Martin Alan Pedersen
  */
 public class Persistence
 {
 	
 	//:://////////////////////////////////////
 	//::  Static Methods
 	//:://////////////////////////////////////
 	
 	public static void setDataDirectory( File newDataDirectory )
 	{
 		Persistence.dataDirectory = newDataDirectory;
 	}
 
 	/**
 	 * Creates a PrintStream that is compatible with RoboCode's file permissions management.
 	 * 
 	 * @param filename the name of the data directory file to be written to
 	 *
 	 * @return a print stream associated with the file
 	 */
 	public static PrintStream getPrintStream( String filename )
 	{
 		PrintStream outputStream = null;
 
 		File dataFile = getDataFile( filename );
 		if( dataFile != null )
 		{
 			try
 			{
 				outputStream = new PrintStream( new RobocodeFileOutputStream( dataFile ) );
 			}
 			catch( Exception ex )
 			{
 				Console.getInstance().log( "Exception thrown opening PrintStream [" + filename + "]." );
 				Console.getInstance().log( ex );
 				if( outputStream != null ) outputStream.close();
 			}
 		}
 
 		return outputStream;
 	}
 
 	/**
 	 * Places the contents of a file in a CharBuffer.
 	 * 
 	 * @param filename the name of the data directory file to be read from
 	 *
 	 * @return a CharBuffer containing the entire contents of the file
 	 */
 	public static CharBuffer getFileContents( String filename )
 	{
 		CharBuffer fileContents = null;
 		
 		File dataFile = getDataFile( filename );
 		if( dataFile != null )
 		{
 			FileReader inputStream = null;
 			try
 			{
 				inputStream = new FileReader( dataFile );
 				CharBuffer buffer = CharBuffer.allocate( (int)dataFile.length() );
 				if( inputStream.read( buffer ) == (int)dataFile.length() )
 				{
 					fileContents = buffer;
 				}
 			}
 			catch( Exception ex )
 			{
 				Console.getInstance().log( "Exception thrown reading contents of file [" + filename + "]." );
 				Console.getInstance().log( ex );
 			}
 			finally
 			{
 				try
 				{
 					if( inputStream != null ) inputStream.close();
 				}
 				catch( IOException ex )
 				{
 					Console.getInstance().log( "Exception thrown closing input stream [" + filename + "]." );
 					Console.getInstance().log( ex );
 				}
 			}
 		}
 		
 		return fileContents;
 	}
 	
 	/**
 	 * Writes a list of strings to a file.
 	 * 
 	 * @param list the list of strings
 	 * @param filename the name of the file to write to
 	 */
 	public static void writeListToFile( String filename, List list )
 	{
 		PrintStream outputStream = getPrintStream( filename );
 		if( outputStream != null )
 		{
 			try
 			{
 				Iterator iterator = list.iterator();
 				while( iterator.hasNext() )
 				{
 					outputStream.println( encrypt( (String) iterator.next() ) );
 				}
 			}
 			catch( Exception ex )
 			{
 				Console.getInstance().log( "Exception thrown writing list to file" );
 				Console.getInstance().log( ex );
 			}
 			finally
 			{
 				if( outputStream != null ) outputStream.close();
 			}
 		}
 	}
 
 	/**
 	 * Reads a file and converts each line into a list entry.
 	 * 
 	 * @param filename the name of the file to read.
 	 * 
 	 * @return the lines of the file in the form of a list
 	 */
 	public static List readListFromFile( String filename )
 	{
 		List list = new ArrayList();
 
 		CharBuffer fileContents = getFileContents( filename );
 		if( fileContents != null )
 		{
 			String buffer = fileContents.toString();
 			int indexStart = 0;
 			int indexEnd = buffer.indexOf( "\n", indexStart );
 			while( indexEnd != -1 )
 			{
 				list.add( decrypt( buffer.substring( indexStart, indexEnd ) ) );
 				indexStart = indexEnd + 1;
 				indexEnd = buffer.indexOf( "\n", indexStart );
 			}
 		}
 
 		return list;
 	}
 
 
 	/**
 	 * Gets a data directory file.
 	 * 
 	 * @param filename the name of the data file
 	 * 
 	 * @return a File object associated with the data file
 	 */
 	private static File getDataFile( String filename )
 	{
 		File dataFile = null;
 		
 		if( dataDirectory != null )
 		{
 			dataFile = new File( dataDirectory, mangle( filename ) );
 		}
 
 		if( dataFile == null )
 		{
 			Console.getInstance().log( "Access to file [" + filename + "] is denied." );
 		}
 
 		return dataFile;
 	}
 	
 	
 	/**
 	 * Converts readable data into encrypted data.
 	 * 
 	 * @param readable the readable data
 	 * 
 	 * @return encrypted data
 	 */
 	private static String encrypt( String readable )
 	{
 		String unreadable = null;
 		unreadable = readable; // placeholder
 		return unreadable;
 	}
 	
 	
 	/**
 	 * Converts encrypted data into readable data.
 	 * 
 	 * @param unreadable encrypted data
 	 * 
 	 * @return readable data
 	 */
 	private static String decrypt( String unreadable )
 	{
 		String readable = null;
 		readable = unreadable; // placeholder
 		return readable;
 	}
 	
 	
 	/**
 	 * Converts a string into a file-friendly one.  Intended for converting tank names.
 	 * 
 	 * @param original the original name
 	 * 
 	 * @return the converted filename
 	 */
 	private static String mangle( String original )
 	{
 		StringBuffer buffer = new StringBuffer();
 		char character;
 		for( int i = 0; i < original.length(); i++ )
 		{
 			character = original.charAt( i );
 			if( ( character > 47 ) && ( character < 58 ) ) buffer.append( character );
 			else if( ( character > 64 ) && ( character < 91 ) ) buffer.append( character );
 			else if( ( character > 96 ) && ( character < 123 ) ) buffer.append( character );
 		}
 		buffer.append( ".txt" );
 		return buffer.toString();
 	}
 
 	//:://////////////////////////////////////
 	//::  Static Variables
 	//:://////////////////////////////////////
 	
 	private static File dataDirectory = null;
 
 }