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There is a newer version: 1.5.0

/*
 * 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 cn.hippo4j.common.executor.support;

import java.util.concurrent.BlockingQueue;
import java.util.concurrent.RejectedExecutionHandler;
import java.util.concurrent.ThreadPoolExecutor;

/**
 * Run the oldest task policy.
 */
public class RunsOldestTaskPolicy implements RejectedExecutionHandler {

    @Override
    public void rejectedExecution(Runnable r, ThreadPoolExecutor executor) {
        if (executor.isShutdown()) {
            return;
        }
        BlockingQueue workQueue = executor.getQueue();
        Runnable firstWork = workQueue.poll();
        boolean newTaskAdd = workQueue.offer(r);
        if (firstWork != null) {
            firstWork.run();
        }
        if (!newTaskAdd) {
            executor.execute(r);
        }
    }
}