Files
narya/src/java/com/threerings/util/TrackedObject.java
T
Ray Greenwell 174d0ac3ad It turns out that a cloned Object does not call any instance initializers,
which makes sense when you think about it, so we now increment the instance
when an object is cloned or created.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@3107 542714f4-19e9-0310-aa3c-eee0fc999fb1
2004-08-28 01:23:31 +00:00

111 lines
3.7 KiB
Java

//
// $Id: TrackedObject.java,v 1.6 2004/08/28 01:23:31 ray Exp $
//
// Narya library - tools for developing networked games
// Copyright (C) 2002-2004 Three Rings Design, Inc., All Rights Reserved
// http://www.threerings.net/code/narya/
//
// This library is free software; you can redistribute it and/or modify it
// under the terms of the GNU Lesser General Public License as published
// by the Free Software Foundation; either version 2.1 of the License, or
// (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
package com.threerings.util;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import com.samskivert.util.Tuple;
/**
* Used to perform rudimentary memory profiling on large, running systems
* where it is impractical to operate a real profiler. Instances of {@link
* TrackedObject} record their existence when constructed and their
* destruction when finalized which, combined with periodic queries of the
* current total object count (by class) logged and graphed (gnuplot is
* your friend), can provide an indication of systems that are improperly
* retaining references.
*/
public class TrackedObject
{
// instance initializer - called whenever an instance is constructed
{
incrementInstanceCount();
}
// documentation inherited
protected Object clone ()
throws CloneNotSupportedException
{
Object o = super.clone();
incrementInstanceCount();
return o;
}
/** Records that this object came into existence. */
protected final void incrementInstanceCount ()
{
Class clazz = getClass();
synchronized (_map) {
int[] count = (int[])_map.get(clazz);
if (count == null) {
_map.put(clazz, count = new int[1]);
}
count[0]++;
}
}
/** Records that this object was collected. */
protected void finalize ()
throws Throwable
{
Class clazz = getClass();
synchronized (_map) {
int[] count = (int[])_map.get(clazz);
if (count != null) {
count[0]--;
} else {
Log.warning("Finalized TrackedObject missing counter! " +
"[class=" + clazz + "].");
}
}
super.finalize();
}
/**
* Returns a {@link Tuple} containing an array of {@link Class}
* instances and an <code>int[]</code> array that represent the number
* of outstanding instance of all {@link TrackedObject}s in the VM.
*/
public static Tuple getSnapshot ()
{
Class[] classes = null;
int[] counts = null;
synchronized (_map) {
classes = new Class[_map.size()];
counts = new int[_map.size()];
Iterator iter = _map.entrySet().iterator();
for (int ii = 0; iter.hasNext(); ii++) {
Map.Entry entry = (Map.Entry)iter.next();
classes[ii] = (Class)entry.getKey();
counts[ii] = ((int[])entry.getValue())[0];
}
}
return new Tuple(classes, counts);
}
/** Tracks a mapping from {@link Class} object to active count. */
protected static HashMap _map = new HashMap();
}