29.4. 分数配置

流程

1. 在 Cloud BalancingSolverConfig.xml 文件中，添加或取消注释设置：

     <scoreDirectorFactory>
       <easyScoreCalculatorClass>org.optaplanner.examples.cloudbalancing.optional.score.CloudBalancingEasyScoreCalculator</easyScoreCalculatorClass>
     </scoreDirectorFactory>

2. 实施 compute Score (Solution) 方法，以返回 Hard SoftScore 实例。

   例 29.6. CloudBalancingEasyScoreCalculator.java

   public class CloudBalancingEasyScoreCalculator implements EasyScoreCalculator<CloudBalance> {
   
       /**
        * A very simple implementation. The double loop can easily be removed by using Maps as shown in
        * {@link CloudBalancingMapBasedEasyScoreCalculator#calculateScore(CloudBalance)}.
        */
       public HardSoftScore calculateScore(CloudBalance cloudBalance) {
           int hardScore = 0;
           int softScore = 0;
           for (CloudComputer computer : cloudBalance.getComputerList()) {
               int cpuPowerUsage = 0;
               int memoryUsage = 0;
               int networkBandwidthUsage = 0;
               boolean used = false;
   
               // Calculate usage
               for (CloudProcess process : cloudBalance.getProcessList()) {
                   if (computer.equals(process.getComputer())) {
                       cpuPowerUsage += process.getRequiredCpuPower();
                       memoryUsage += process.getRequiredMemory();
                       networkBandwidthUsage += process.getRequiredNetworkBandwidth();
                       used = true;
                   }
               }
   
               // Hard constraints
               int cpuPowerAvailable = computer.getCpuPower() - cpuPowerUsage;
               if (cpuPowerAvailable < 0) {
                   hardScore += cpuPowerAvailable;
               }
               int memoryAvailable = computer.getMemory() - memoryUsage;
               if (memoryAvailable < 0) {
                   hardScore += memoryAvailable;
               }
               int networkBandwidthAvailable = computer.getNetworkBandwidth() - networkBandwidthUsage;
               if (networkBandwidthAvailable < 0) {
                   hardScore += networkBandwidthAvailable;
               }
   
               // Soft constraints
               if (used) {
                   softScore -= computer.getCost();
               }
           }
           return HardSoftScore.valueOf(hardScore, softScore);
       }
   
   }

流程

1. 在 classpath 中添加 scoreDrl 资源，以使用决策引擎作为分数功能。在 Cloud BalancingSolverConfig.xml 文件中，添加或取消注释设置：

     <scoreDirectorFactory>
       <scoreDrl>org/optaplanner/examples/cloudbalancing/solver/cloudBalancingScoreRules.drl</scoreDrl>
     </scoreDirectorFactory>

2. 创建硬限制。这些限制可确保所有计算机有足够的 CPU、RAM 和网络带宽来支持其所有进程：

   例 29.7. cloudBalancingScoreRules.drl - Hard Constraints

   ...
   
   import org.optaplanner.examples.cloudbalancing.domain.CloudBalance;
   import org.optaplanner.examples.cloudbalancing.domain.CloudComputer;
   import org.optaplanner.examples.cloudbalancing.domain.CloudProcess;
   
   global HardSoftScoreHolder scoreHolder;
   
   // ############################################################################
   // Hard constraints
   // ############################################################################
   
   rule "requiredCpuPowerTotal"
       when
           $computer : CloudComputer($cpuPower : cpuPower)
           accumulate(
               CloudProcess(
                   computer == $computer,
                   $requiredCpuPower : requiredCpuPower);
               $requiredCpuPowerTotal : sum($requiredCpuPower);
               $requiredCpuPowerTotal > $cpuPower
           )
       then
           scoreHolder.addHardConstraintMatch(kcontext, $cpuPower - $requiredCpuPowerTotal);
   end
   
   rule "requiredMemoryTotal"
       ...
   end
   
   rule "requiredNetworkBandwidthTotal"
       ...
   end

3. 创建软约束。此约束可最小化维护成本。只有在满足硬限制时才会应用它：

   例 29.8. cloudBalancingScoreRules.drl - Soft Constraints

   // ############################################################################
   // Soft constraints
   // ############################################################################
   
   rule "computerCost"
       when
           $computer : CloudComputer($cost : cost)
           exists CloudProcess(computer == $computer)
       then
           scoreHolder.addSoftConstraintMatch(kcontext, - $cost);
   end