/*
* Druid - a distributed column store.
* Copyright (C) 2012, 2013 Metamarkets Group Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package io.druid.collections;
import com.google.common.base.Supplier;
import com.google.common.collect.Lists;
import com.metamx.common.ISE;
import com.metamx.common.logger.Logger;
import java.io.IOException;
import java.util.LinkedList;
/**
*/
public class StupidPool<T>
{
private static final Logger log = new Logger(StupidPool.class);
private final Supplier<T> generator;
private final LinkedList<T> objects = Lists.newLinkedList();
public StupidPool(
Supplier<T> generator
)
{
this.generator = generator;
}
public ResourceHolder<T> take()
{
synchronized (objects) {
if (objects.size() > 0) {
return new ObjectResourceHolder(objects.removeFirst());
}
}
return new ObjectResourceHolder(generator.get());
}
private class ObjectResourceHolder implements ResourceHolder<T>
{
private boolean closed = false;
private final T object;
public ObjectResourceHolder(final T object)
{
this.object = object;
}
@Override
public synchronized T get()
{
if (closed) {
throw new ISE("Already Closed!");
}
return object;
}
@Override
public synchronized void close() throws IOException
{
if (closed) {
log.warn(new ISE("Already Closed!"), "Already closed");
return;
}
synchronized (objects) {
closed = true;
objects.addLast(object);
}
}
@Override
protected void finalize() throws Throwable
{
if (! closed) {
log.warn("Not closed! Object was[%s]. Allowing gc to prevent leak.", object);
}
}
}
}