Util.java

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package org.openslx.imagemaster.util;

import java.io.File;
import java.math.BigInteger;
import java.security.Key;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.util.Arrays;
import java.util.Random;
import java.util.UUID;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

public class Util
{

   private static Logger LOGGER = LogManager.getLogger( Util.class );

   public static void notNullFatal( Object something, String message )
   {
      if ( something == null ) {
         if ( message != null )
            LOGGER.fatal( "[NOTNULL] " + message, new NullPointerException() );
         System.exit( 2 );
      }
   }

   public static void notNullFatal( int number, String message )
   {
      if ( number == 0 ) {
         if ( message != null )
            LOGGER.fatal( "[NOTNULL] " + message, new NullPointerException() );
         System.exit( 2 );
      }
   }

   public static void notNullOrEmptyFatal( String something, String message )
   {
      if ( something == null || something.isEmpty() ) {
         if ( message != null )
            LOGGER.fatal( "[NOTNULL] " + message, new NullPointerException() );
         System.exit( 2 );
      }
   }

   private static final Random random = new Random();

   public static int randomInt( int n )
   {
      return random.nextInt( n );
   }

   public static void deleteFolder( File folder )
   {
      File[] files = folder.listFiles();
      if ( files != null ) {
         for ( File f : files ) {
            if ( f.isDirectory() ) {
               deleteFolder( f );
            } else {
               f.delete();
            }
         }
      }
      folder.delete();
   }

   public static boolean isEmpty( String str )
   {
      return str == null || str.isEmpty();
   }

   public static boolean isEmpty( String str, String message, Logger logger )
   {
      if ( str != null && !str.isEmpty() )
         return false;
      logger.debug( message );
      return true;
   }

   public static int tryToParseInt( String s )
   {
      return tryToParseInt( s, 0 );
   }

   public static int tryToParseInt( String s, int defaultValue )
   {
      try {
         return Integer.parseInt( s );
      } catch ( NumberFormatException e ) {
         return defaultValue;
      }
   }

   public static BigInteger tryToParseBigInt( String s )
   {
      try {
         return new BigInteger( s );
      } catch ( NumberFormatException e ) {
         return null;
      }
   }

   public static int getNumberOfBlocks( long fileSize, int blockSize )
   {
      int blocks = (int) ( fileSize / blockSize );
      if ( fileSize % blockSize != 0 )
         blocks++;
      return blocks;
   }

   public static String sanitizeFileName( String fileName )
   {
      fileName = fileName.replaceAll( "[^a-zA-Z0-9_\\-]+", "_" );
      if ( fileName.length() > 40 )
         fileName = fileName.substring( 0, 40 );
      return fileName;
   }

   public static boolean keysEqual( Key k1, Key k2 )
   {
      if ( k1 instanceof RSAPublicKey && k2 instanceof RSAPublicKey )
      {
         RSAPublicKey rsa1 = (RSAPublicKey)k1;
         RSAPublicKey rsa2 = (RSAPublicKey)k2;
         return rsa1.getModulus().equals( rsa2.getModulus() )
               && rsa1.getPublicExponent().equals( rsa2.getPublicExponent() );
      }

      if ( k1 instanceof RSAPrivateKey && k2 instanceof RSAPrivateKey )
      {
         RSAPrivateKey rsa1 = (RSAPrivateKey)k1;
         RSAPrivateKey rsa2 = (RSAPrivateKey)k2;
         return rsa1.getModulus().equals( rsa2.getModulus() )
               && rsa1.getPrivateExponent().equals( rsa2.getPrivateExponent() );
      }
      return Arrays.equals( k1.getEncoded(), k2.getEncoded() );
   }

   public static String getRelativePath( File absolutePath, File parentDir )
   {
      String file;
      String dir;
      try {
         file = absolutePath.getCanonicalPath();
         dir = parentDir.getCanonicalPath() + File.separator;
      } catch ( Exception e ) {
         LOGGER.error( "Could not get relative path for " + absolutePath.toString(), e );
         return null;
      }
      if ( !file.startsWith( dir ) )
         return null;
      return file.substring( dir.length() );
   }

   public static boolean isUUID( String id )
   {
      try {
         UUID.fromString( id );
      } catch ( Exception e ) {
         return false;
      }
      return true;
   }

}