001    /* java.lang.ref.SoftReference
002       Copyright (C) 1999, 2004 Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010     
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package java.lang.ref;
040    
041    /**
042     * A soft reference will be cleared, if the object is only softly
043     * reachable and the garbage collection needs more memory.  The garbage
044     * collection will use an intelligent strategy to determine which soft
045     * references it should clear.  This makes a soft reference ideal for
046     * caches.<br>
047     *
048     * @author Jochen Hoenicke 
049     */
050    public class SoftReference<T>
051      extends Reference<T>
052    {
053      /**
054       * Create a new soft reference, that is not registered to any queue.
055       * @param referent the object we refer to.
056       */
057      public SoftReference(T referent)
058      {
059        super(referent);
060      }
061    
062      /**
063       * Create a new soft reference.
064       * @param referent the object we refer to.
065       * @param q the reference queue to register on.
066       * @exception NullPointerException if q is null.
067       */
068      public SoftReference(T referent, ReferenceQueue<? super T> q)
069      {
070        super(referent, q);
071      }
072      
073      /**
074       * Returns the object, this reference refers to.
075       * @return the object, this reference refers to, or null if the 
076       * reference was cleared.
077       */
078      public T get()
079      {
080        /* Why is this overloaded??? 
081         * Maybe for a kind of LRU strategy. */
082        return super.get();
083      }
084    }