package org.apache.maven.lifecycle.internal;
   
   /*
    * 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.
   */
  
  import org.codehaus.plexus.component.annotations.Component;
  import org.codehaus.plexus.component.annotations.Requirement;
  import org.codehaus.plexus.logging.Logger;
  
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Executors;
  
  /**
   * @since 3.0
   */
  @Component( role = ThreadConfigurationService.class )
  public class ThreadConfigurationService
  {
      @Requirement
      private Logger logger;
  
      private final int cpuCores;
  
  
      public ThreadConfigurationService()
      {
          cpuCores = Runtime.getRuntime().availableProcessors();
      }
  
      public ThreadConfigurationService( Logger logger, int cpuCores )
      {
          this.logger = logger;
          this.cpuCores = cpuCores;
      }
  
  
      public ExecutorService getExecutorService( String threadCountConfiguration, boolean perCoreThreadCount,
                                                 int largestBuildListSize )
      {
          Integer threadCount = getThreadCount( threadCountConfiguration, perCoreThreadCount, largestBuildListSize );
          return getExecutorService( threadCount );
  
  
      }
  
      private ExecutorService getExecutorService( Integer threadCount )
      {
          if ( threadCount == null )
          {
              logger.info( "Building with unlimited threads" );
              return Executors.newCachedThreadPool();
          }
  
          logger.info( "Building with " + threadCount + " threads" );
          return Executors.newFixedThreadPool( threadCount );
      }
  
      /**
       * Returns the thread count to use or null for unlimited threads.
       *
       * @param threadCountConfiguration The property passed from the command line.
       * @param perCoreThreadCount       Indicates if the threa count should be scaled per cpu core.
       * @param largestBuildListSize     the size of the largest module list (the number of modules)
       * @return The number of threads to use or null if unlimited
       */
  
      Integer getThreadCount( String threadCountConfiguration, boolean perCoreThreadCount, int largestBuildListSize )
      {
          // Default to a value that is not larger than what we can use ;)
          float threadCount = Math.min( cpuCores, largestBuildListSize );
          if ( threadCountConfiguration != null )
          {
              try
              {
                  threadCount = Float.parseFloat( threadCountConfiguration );
              }
              catch ( NumberFormatException e )
              {
                  logger.warn(
                      "Couldn't parse thread count, will default to " + threadCount + ": " + threadCountConfiguration );
              }
          }
          if ( perCoreThreadCount )
         {
             threadCount = threadCount * cpuCores;
         }
 
         final int endResult = Math.round( threadCount );
         if ( logger.isDebugEnabled() )
         {
             logger.debug( "Thread pool size: " + endResult );
         }
         return endResult;
     }
 }