1 /*
   2  * Copyright (c) 2002, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 import java.nio.ByteBuffer;
  25 import java.util.Properties;
  26 
  27 public class LimitDirectMemory {
  28     private static final int K = 1024;
  29 
  30     public static void main(String [] args) throws Exception {
  31         if (args.length < 2)
  32             throw new RuntimeException();
  33         boolean throwp = parseThrow(args[0]);
  34         int size = parseSize(args[1]);
  35         int incr = (args.length > 2 ? parseSize(args[2]) : size);
  36 
  37         Properties p = System.getProperties();
  38         if (p.getProperty("sun.nio.MaxDirectMemorySize") != null)
  39             throw new RuntimeException("sun.nio.MaxDirectMemorySize defined");
  40 
  41         ByteBuffer [] b = new ByteBuffer[K];
  42 
  43         // Fill up most/all of the direct memory
  44         int i = 0;
  45         while (size >= incr) {
  46             b[i++] = ByteBuffer.allocateDirect(incr);
  47             size -= incr;
  48         }
  49 
  50         if (throwp) {
  51             try {
  52                 b[i] = ByteBuffer.allocateDirect(incr);
  53                 throw new RuntimeException("OutOfMemoryError not thrown: "
  54                                            + incr);
  55             } catch (OutOfMemoryError e) {
  56                 e.printStackTrace(System.out);
  57                 System.out.println("OK - Error thrown as expected ");
  58             }
  59         } else {
  60             b[i] = ByteBuffer.allocateDirect(incr);
  61             System.out.println("OK - Error not thrown");
  62         }
  63     }
  64 
  65     private static boolean parseThrow(String s) {
  66         if (s.equals("true"))  return true;
  67         if (s.equals("false")) return false;
  68         throw new RuntimeException("Unrecognized expectation: " + s);
  69     }
  70 
  71     private static int parseSize(String size) throws Exception {
  72 
  73         if (size.equals("DEFAULT"))
  74             return (int)Runtime.getRuntime().maxMemory();
  75         if (size.equals("DEFAULT+1"))
  76             return (int)Runtime.getRuntime().maxMemory() + 1;
  77         if (size.equals("DEFAULT+1M"))
  78             return (int)Runtime.getRuntime().maxMemory() + (1 << 20);
  79         if (size.equals("DEFAULT-1"))
  80             return (int)Runtime.getRuntime().maxMemory() - 1;
  81         if (size.equals("DEFAULT/2"))
  82             return (int)Runtime.getRuntime().maxMemory() / 2;
  83 
  84         int idx = 0, len = size.length();
  85 
  86 
  87         for (int i = 0; i < len; i++) {
  88             if (Character.isDigit(size.charAt(i))) idx++;
  89             else break;
  90         }
  91 
  92         if (idx == 0)
  93             throw new RuntimeException("No digits detected: " + size);
  94 
  95         int result = Integer.parseInt(size.substring(0, idx));
  96 
  97         if (idx < len) {
  98             for (int i = idx; i < len; i++) {
  99                 switch(size.charAt(i)) {
 100                 case 'T': case 't': result *= K; // fall through
 101                 case 'G': case 'g': result *= K; // fall through
 102                 case 'M': case 'm': result *= K; // fall through
 103                 case 'K': case 'k': result *= K;
 104                     break;
 105                 default:
 106                     throw new RuntimeException("Unrecognized size: " + size);
 107                 }
 108             }
 109         }
 110         return result;
 111     }
 112 }