ui/src/main/java/org/akraino/validation/ui/conf/ExecutorServiceInitializer.java

   1 /*
   2  * Copyright (c) 2019 AT&T Intellectual Property. All rights reserved.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License"); you may
   5  * not use this file except in compliance with the License. You may obtain
   6  * a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
  13  * implied. See the License for the specific language governing
  14  * permissions and limitations under the License.
  15  */
  16 package org.akraino.validation.ui.conf;
  17
  18 import java.lang.reflect.Field;
  19 import java.util.Comparator;
  20 import java.util.concurrent.ExecutorService;
  21 import java.util.concurrent.PriorityBlockingQueue;
  22 import java.util.concurrent.ThreadPoolExecutor;
  23 import java.util.concurrent.TimeUnit;
  24
  25 import org.springframework.context.annotation.Bean;
  26 import org.springframework.context.annotation.Configuration;
  27
  28 @Configuration
  29 public class ExecutorServiceInitializer {
  30
  31     private static final int QUEUE_CAPACITY = 500;
  32     private static final int EXECUTOR_SIZE = 30; // the number of threads to keep in the pool, even if
  33     // they are idle, unless allowCoreThreadTimeOut is
  34     // set
  35     private static final int EXECUTOR_MAX_SIZE = 30; // the maximum number of threads to allow in the pool
  36     private static final int KEEPALIVE_TIME = 30; // when the number of threads is greater than the
  37     // core, this is the maximum time that excess idle
  38     // threads will wait for new tasks before
  39     // terminating.
  40     private static final PriorityBlockingQueue<Runnable> BLOCKING_QUEUE = new PriorityBlockingQueue<Runnable>(
  41             QUEUE_CAPACITY, new CFRunnableComparator());
  42     private static ExecutorService executorService = new ThreadPoolExecutor(EXECUTOR_SIZE, EXECUTOR_MAX_SIZE,
  43             KEEPALIVE_TIME, TimeUnit.SECONDS, BLOCKING_QUEUE);
  44
  45     @Bean(name = "executorService")
  46     public ExecutorService getExecutorService() {
  47         return this.executorService;
  48     }
  49
  50     private static class CFRunnableComparator implements Comparator<Runnable> {
  51         @Override
  52         @SuppressWarnings("unchecked")
  53         public int compare(Runnable runnable1, Runnable runnable2) {
  54             return ((Comparable) unwrap(runnable1)).compareTo(unwrap(runnable2));
  55         }
  56
  57         private Object unwrap(Runnable runnable) {
  58             try {
  59                 Field field = runnable.getClass().getDeclaredField("fn");
  60                 field.setAccessible(true);
  61                 return field.get(runnable);
  62             } catch (IllegalAccessException | NoSuchFieldException e) {
  63                 throw new IllegalArgumentException("Couldn't unwrap " + runnable, e);
  64             }
  65         }
  66     }
  67
  68 }