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1   /*
2    *  Licensed to the Apache Software Foundation (ASF) under one or more
3    *  contributor license agreements.  See the NOTICE file distributed with
4    *  this work for additional information regarding copyright ownership.
5    *  The ASF licenses this file to You under the Apache License, Version 2.0
6    *  (the "License"); you may not use this file except in compliance with
7    *  the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   *  Unless required by applicable law or agreed to in writing, software
12   *  distributed under the License is distributed on an "AS IS" BASIS,
13   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   *  See the License for the specific language governing permissions and
15   *  limitations under the License.
16   *
17   */
18  package org.codehaus.plexus.archiver.zip;
19  
20  import java.util.concurrent.ExecutorService;
21  import java.util.concurrent.LinkedBlockingQueue;
22  import java.util.concurrent.ThreadFactory;
23  import java.util.concurrent.ThreadPoolExecutor;
24  import java.util.concurrent.TimeUnit;
25  import java.util.concurrent.atomic.AtomicInteger;
26  
27  /**
28   * Classic (pre Java 21) implementation. Create one thread eagerly, but allow pool to scale up to provided
29   * number (usually set to Java reported CPU count). Apply same thread names as well.
30   *
31   * @since 4.10.1
32   */
33  public class ConcurrentJarCreatorExecutorServiceFactory {
34      private static final AtomicInteger POOL_COUNTER = new AtomicInteger();
35  
36      static ExecutorService createExecutorService(int poolSize) {
37          ThreadGroup threadGroup = Thread.currentThread().getThreadGroup();
38          int poolCount = POOL_COUNTER.incrementAndGet();
39          AtomicInteger threadCounter = new AtomicInteger();
40          ThreadFactory threadFactory = new ThreadFactory() {
41              @Override
42              public Thread newThread(Runnable r) {
43                  Thread thread =
44                          new Thread(threadGroup, r, "plx-arch-" + poolCount + "-" + threadCounter.incrementAndGet());
45                  thread.setDaemon(true);
46                  return thread;
47              }
48          };
49          return new ThreadPoolExecutor(1, poolSize, 1L, TimeUnit.SECONDS, new LinkedBlockingQueue<>(), threadFactory);
50      }
51  }