| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.flink.statefun.flink.core.pool; |
| |
| import java.util.ArrayDeque; |
| import java.util.Objects; |
| import java.util.function.Supplier; |
| import javax.annotation.concurrent.NotThreadSafe; |
| |
| /** |
| * Simple element pool. |
| * |
| * @param <ElementT> type of elements being pooled. |
| */ |
| @NotThreadSafe |
| public final class SimplePool<ElementT> { |
| private final ArrayDeque<ElementT> elements = new ArrayDeque<>(); |
| private final Supplier<ElementT> supplier; |
| private final int maxCapacity; |
| |
| public SimplePool(Supplier<ElementT> supplier, int maxCapacity) { |
| this.supplier = Objects.requireNonNull(supplier); |
| this.maxCapacity = maxCapacity; |
| } |
| |
| public ElementT get() { |
| ElementT element = elements.pollFirst(); |
| if (element != null) { |
| return element; |
| } |
| return supplier.get(); |
| } |
| |
| public void release(ElementT item) { |
| if (elements.size() < maxCapacity) { |
| elements.addFirst(item); |
| } |
| } |
| } |