    1   /* TestUtils
    2   *
    3   * $Id: TestUtils.java 4644 2006-09-20 22:40:21Z paul_jack $
    4   *
    5   * Created on Dec 28, 2004
    6   *
    7   * Copyright (C) 2004 Internet Archive.
    8   *
    9   * This file is part of the Heritrix web crawler (crawler.archive.org).
    10  *
    11  * Heritrix is free software; you can redistribute it and/or modify
    12  * it under the terms of the GNU Lesser Public License as published by
    13  * the Free Software Foundation; either version 2.1 of the License, or
    14  * any later version.
    15  *
    16  * Heritrix is distributed in the hope that it will be useful,
    17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
    18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    19  * GNU Lesser Public License for more details.
    20  *
    21  * You should have received a copy of the GNU Lesser Public License
    22  * along with Heritrix; if not, write to the Free Software
    23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
    24  */
    25  package org.archive.util;
    26
    27  import java.lang.ref.SoftReference;
    28  import java.util.LinkedList;
    29
    30  /***
    31   * Utility methods useful in testing situations.
    32   *
    33   * @author gojomo
    34   */
    35  public class TestUtils {
    36
    37      /***
    38       * Temporarily exhaust memory, forcing weak/soft references to
    39       * be broken.
    40       */
    41      public static void forceScarceMemory() {
    42          // force soft references to be broken
    43          LinkedList<SoftReference> hog = new LinkedList<SoftReference>();
    44          long blocks = Runtime.getRuntime().maxMemory() / 1000000;
    45          for(long l = 0; l <= blocks; l++) {
    46              try {
    47                  hog.add(new SoftReference<byte[]>(new byte[1000000]));
    48              } catch (OutOfMemoryError e) {
    49                  hog = null;
    50                  break;
    51              }
    52          }
    53      }
    54  }