1 /*

     2  * Copyright (c) 2002, 2010, 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 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         int result = 1;

    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         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 }