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[] lists;

     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();

         }

     }

     public void addTest( PrioritizedTest prioritizedTest )

     {

         final int leastBusySlot = findLeastBusySlot();

         runTime[leastBusySlot] += prioritizedTest.getTotalRuntime();

         lists[leastBusySlot].add( prioritizedTest.getClazz() );

     }

     public List getResult()

     {

         List result = new ArrayList();

         int index = 0;

         boolean added = false;

         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;

     }

 }