package org.apache.maven.plugin.surefire.runorder;
   
   /*
    * 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 java.util.ArrayList;
  import java.util.List;
  
  
  /**
   * @author Kristian Rosenvold
   */
  public class ThreadedExecutionScheduler
  {
      private final int numThreads;
  
      private final int runTime[];
  
      private final List<Class<?>>[] lists;
  
      @SuppressWarnings( "unchecked" )
      public ThreadedExecutionScheduler( int numThreads )
      {
          this.numThreads = numThreads;
          runTime = new int[numThreads];
          lists = new List[numThreads];
          for ( int i = 0; i < numThreads; i++ )
          {
              lists[i] = new ArrayList<Class<?>>();
          }
      }
  
      public void addTest( PrioritizedTest prioritizedTest )
      {
          final int leastBusySlot = findLeastBusySlot();
          runTime[leastBusySlot] += prioritizedTest.getTotalRuntime();
          //noinspection unchecked
          lists[leastBusySlot].add( prioritizedTest.getClazz() );
      }
  
      public List<Class<?>> getResult()
      {
          List<Class<?>> result = new ArrayList<Class<?>>();
          int index = 0;
          boolean added;
          do
          {
              added = false;
              for ( int i = 0; i < numThreads; i++ )
              {
                  if ( lists[i].size() > index )
                  {
                      result.add( lists[i].get( index ) );
                      added = true;
                  }
              }
              index++;
          }
          while ( added );
          return result;
      }
  
      private int findLeastBusySlot()
      {
          int leastBusy = 0;
          int minRuntime = runTime[0];
          for ( int i = 1; i < numThreads; i++ )
          {
              if ( runTime[i] < minRuntime )
              {
                  leastBusy = i;
                  minRuntime = runTime[i];
              }
          }
          return leastBusy;
      }
  }