Optaplanner 解决失败的“非法状态异常”

Question

我是 optaPlanner 的新手，我正在尝试通过更改晚宴示例来更好地学习如何使用它来解决不同类型的问题。我添加了一个名为sameSleepingPreference 的新评分规则，它使用我创建的一个名为sleepingPreference 的新枚举，它是客人的一个属性。具有相同睡眠偏好的人被放在一起。

rule "sameSleepingPreference"
    when
        $leftDesignation : SeatDesignation($leftGuest : guest)
        $rightDesignation : SeatDesignation(isRightOf($leftDesignation), $rightGuest : guest)

       eval($leftGuest.sleepingPreference.equals($rightGuest.sleepingPreference))
    then
        scoreHolder.addConstraintMatch(kcontext, +1);
end 

当我尝试使用只有四个人的数据表运行 optaPlanner 时，该示例运行良好。但是，通过更改晚宴示例中的一张原始数据表，我列出了更长的 144 人列表，它给了我这个错误：

2015-07-23 10:41:59,414 [AWT-EventQueue-0] INFO Opened: data\dinnerparty\unsolved\hannahWeddingTest.xml 2015-07-23 10:42:01,012 [SwingWorker-pool-4-thread-1] INFO Solving started: time spent (97), best score (uninitialized/-14400), environment mode (REPRODUCIBLE), random (JDK with seed 0). Exception in thread "AWT-EventQueue-0" java.lang.IllegalStateException: Solving failed. at org.optaplanner.examples.common.swingui.SolverAndPersistenceFrame$SolveWorker.done(SolverAndPersistenceFrame.java:297) at javax.swing.SwingWorker$5.run(Unknown Source) at javax.swing.SwingWorker$DoSubmitAccumulativeRunnable.run(Unknown Source) at sun.swing.AccumulativeRunnable.run(Unknown Source) at javax.swing.SwingWorker$DoSubmitAccumulativeRunnable.actionPerformed(Unknown Source) at javax.swing.Timer.fireActionPerformed(Unknown Source) at javax.swing.Timer$DoPostEvent.run(Unknown Source) at java.awt.event.InvocationEvent.dispatch(Unknown Source) at java.awt.EventQueue.dispatchEventImpl(Unknown Source) at java.awt.EventQueue.access$300(Unknown Source) at java.awt.EventQueue$3.run(Unknown Source) at java.awt.EventQueue$3.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source) Caused by: java.lang.RuntimeException: org.optaplanner.examples.dinnerparty.solver.Rule_sameSleepingPreference1438171934Eval0Invoker@a59a25b3 : java.lang.NullPointerException at org.drools.core.rule.EvalCondition.isAllowed(EvalCondition.java:123) at org.drools.core.phreak.PhreakEvalNode.doLeftInserts(PhreakEvalNode.java:55) at org.drools.core.phreak.PhreakEvalNode.doNode(PhreakEvalNode.java:39) at org.drools.core.phreak.RuleNetworkEvaluator.innerEval(RuleNetworkEvaluator.java:342) at org.drools.core.phreak.RuleNetworkEvaluator.outerEval(RuleNetworkEvaluator.java:161) at org.drools.core.phreak.RuleNetworkEvaluator.evaluateNetwork(RuleNetworkEvaluator.java:116) at org.drools.core.phreak.RuleExecutor.reEvaluateNetwork(RuleExecutor.java:231) at org.drools.core.phreak.RuleExecutor.evaluateNetworkAndFire(RuleExecutor.java:106) at org.drools.core.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:1016) at org.drools.core.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1302) at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1289) at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1262) at org.optaplanner.core.impl.score.director.drools.DroolsScoreDirector.calculateScore(DroolsScoreDirector.java:87) at org.optaplanner.examples.dinnerparty.solver.solution.initializer.DinnerPartySolutionInitializer.initializeSeatDesignationList(DinnerPartySolutionInitializer.java:69) at org.optaplanner.examples.dinnerparty.solver.solution.initializer.DinnerPartySolutionInitializer.changeWorkingSolution(DinnerPartySolutionInitializer.java:41) at org.optaplanner.core.impl.phase.custom.DefaultCustomPhase.doStep(DefaultCustomPhase.java:78) at org.optaplanner.core.impl.phase.custom.DefaultCustomPhase.solve(DefaultCustomPhase.java:60) at org.optaplanner.core.impl.solver.DefaultSolver.runPhases(DefaultSolver.java:213) at org.optaplanner.core.impl.solver.DefaultSolver.solve(DefaultSolver.java:176) at org.optaplanner.examples.common.business.SolutionBusiness.solve(SolutionBusiness.java:302) at org.optaplanner.examples.common.swingui.SolverAndPersistenceFrame$SolveWorker.doInBackground(SolverAndPersistenceFrame.java:286) at org.optaplanner.examples.common.swingui.SolverAndPersistenceFrame$SolveWorker.doInBackground(SolverAndPersistenceFrame.java:1) at javax.swing.SwingWorker$1.call(Unknown Source) at java.util.concurrent.FutureTask.run(Unknown Source) at javax.swing.SwingWorker.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: java.lang.NullPointerException at org.optaplanner.examples.dinnerparty.solver.Rule_sameSleepingPreference1438171934.eval0(Rule_sameSleepingPreference1438171934.java:8) at org.optaplanner.examples.dinnerparty.solver.Rule_sameSleepingPreference1438171934Eval0InvokerGenerated.evaluate(Unknown Source) at org.optaplanner.examples.dinnerparty.solver.Rule_sameSleepingPreference1438171934Eval0Invoker.evaluate(Unknown Source) at org.drools.core.rule.EvalCondition.isAllowed(EvalCondition.java:118) ... 27 more

我的 144 人示例是无法解决，还是有其他问题？我试过让睡眠偏好规则从分数中加分和减分，（我使用的是简单分数）但两者都会导致程序失败。

Answer 1

这是编写该规则的推荐方式，因为“eval”已被弃用，并且流口水 == 变成了相等的调用：

rule "sameSleepingPreference"
when
    $leftDesignation : SeatDesignation($leftGuest : guest)
    $rightDesignation : SeatDesignation(isRightOf($leftDesignation), $leftGuest.sleepingPreference == guest.sleepingPreference)
then
    scoreHolder.addConstraintMatch(kcontext, +1);
 end