io.questdb.std.ObjectPool Maven / Gradle / Ivy
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* ___ _ ____ ____
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*
* Copyright (c) 2014-2019 Appsicle
* Copyright (c) 2019-2020 QuestDB
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************/
package io.questdb.std;
import io.questdb.log.Log;
import io.questdb.log.LogFactory;
import org.jetbrains.annotations.NotNull;
/**
* Single threaded object pool based on ObjList. The goal is to optimise intermediate allocation of intermediate objects.
*/
public class ObjectPool implements Mutable {
private final static Log LOG = LogFactory.getLog(ObjectPool.class);
private final ObjList list;
private final ObjectFactory factory;
private int pos = 0;
private int size;
public ObjectPool(@NotNull ObjectFactory factory, int size) {
this.list = new ObjList<>(size);
this.factory = factory;
this.size = size;
fill();
}
@Override
public void clear() {
pos = 0;
}
public T next() {
if (pos == size) {
expand();
}
T o = list.getQuick(pos++);
o.clear();
return o;
}
private void expand() {
fill();
size <<= 1;
LOG.info().$("pool resize [class=").$(factory.getClass().getName()).$(", size=").$(size).$(']').$();
}
private void fill() {
for (int i = 0; i < size; i++) {
list.add(factory.newInstance());
}
}
}