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  1. /*
  2.  * Copyright (c) 2010, Manuel Mausz. All rights reserved.
  3.  *
  4.  * Redistribution and use in source and binary forms, with or without
  5.  * modification, are permitted provided that the following conditions
  6.  * are met:
  7.  *
  8.  *   - Redistributions of source code must retain the above copyright
  9.  *     notice, this list of conditions and the following disclaimer.
  10.  *
  11.  *   - Redistributions in binary form must reproduce the above copyright
  12.  *     notice, this list of conditions and the following disclaimer in the
  13.  *     documentation and/or other materials provided with the distribution.
  14.  *
  15.  *   - The names of the authors may not be used to endorse or promote products
  16.  *     derived from this software without specific prior written permission.
  17.  *
  18.  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  19.  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  20.  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  21.  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  22.  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  23.  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  24.  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  25.  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  26.  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  27.  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  28.  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29.  */
  30.  
  31. import java.util.Collection;
  32. import java.util.Iterator;
  33. import java.io.ObjectOutputStream;
  34. import java.io.IOException;
  35.  
  36. /*
  37.  * Common static methods used by all applications
  38.  *
  39.  * @author Manuel Mausz (0728348)
  40.  */
  41. class Utils
  42. {
  43.   static class Shutdown
  44.     extends java.lang.RuntimeException
  45.   {
  46.     public Shutdown()
  47.     {
  48.       super();
  49.     }
  50.  
  51.     public Shutdown(String message)
  52.     {
  53.       super(message);
  54.     }
  55.   }
  56.  
  57.   /*==========================================================================*/
  58.  
  59.   public static <T> String join(final Collection<T> objs, final String delimiter)
  60.   {
  61.     if (objs == null || objs.isEmpty())
  62.       return "";
  63.     Iterator<T> iter = objs.iterator();
  64.     StringBuffer buffer = new StringBuffer(iter.next().toString());
  65.     while (iter.hasNext())
  66.       buffer.append(delimiter).append(iter.next().toString());
  67.     return buffer.toString();
  68.   }
  69.  
  70.   /*--------------------------------------------------------------------------*/
  71.  
  72.   public static long parseHeaderNum(String[] args, int index)
  73.   {
  74.     long num = -1;
  75.     try
  76.     {
  77.       if (args.length < index + 1)
  78.         throw new NumberFormatException();
  79.       num = Long.parseLong(args[index]);
  80.       if (num <= 0)
  81.         throw new NumberFormatException();
  82.     }
  83.     catch(NumberFormatException e)
  84.     {
  85.       System.err.println("Invalid network paket from peer");
  86.     }
  87.     return num;
  88.   }
  89.  
  90.   /*------------------------------------------------------------------------*/
  91.  
  92.   public static void sendOutput(ObjectOutputStream out, String[] msgs)
  93.     throws IOException
  94.   {
  95.     out.writeUTF("!output " + msgs.length);
  96.     for(String msg : msgs)
  97.       out.writeUTF(msg);
  98.     out.flush();
  99.   }
  100.  
  101.   /*------------------------------------------------------------------------*/
  102.  
  103.   public static void sendOutput(ObjectOutputStream out, String msg)
  104.     throws IOException
  105.   {
  106.     String[] tmp = { msg };
  107.     sendOutput(out, tmp);
  108.   }
  109.  
  110.   /*------------------------------------------------------------------------*/
  111.  
  112.   public static void sendError(ObjectOutputStream out, String[] msgs)
  113.     throws IOException
  114.   {
  115.     out.writeUTF("!error " + msgs.length);
  116.     for(String msg : msgs)
  117.       out.writeUTF(msg);
  118.     out.flush();
  119.   }
  120.  
  121.   /*------------------------------------------------------------------------*/
  122.  
  123.   public static void sendError(ObjectOutputStream out, String msg)
  124.     throws IOException
  125.   {
  126.     String[] tmp = { "Error: " + msg };
  127.     sendError(out, tmp);
  128.   }
  129. }
  130.