Drools Planner 在创建配置器时遇到问题：如何调试

Question

我尝试从 XML 配置创建一个求解器。但整个过程会返回一条毫无意义的神秘错误消息。

我该如何解决这个问题？我怎样才能理解这一点以实际解决类似的问题？

jesvin@Jesvin-Technovia:~/dev/drools/sudoku$ java App 
Exception in thread "main" java.lang.NullPointerException
    at org.drools.planner.core.domain.solution.SolutionDescriptor.processPropertyAnnotations(SolutionDescriptor.java:69)
    at org.drools.planner.core.domain.solution.SolutionDescriptor.<init>(SolutionDescriptor.java:61)
    at org.drools.planner.config.solver.SolverConfig.buildSolutionDescriptor(SolverConfig.java:197)
    at org.drools.planner.config.solver.SolverConfig.buildSolver(SolverConfig.java:167)
    at org.drools.planner.config.XmlSolverConfigurer.buildSolver(XmlSolverConfigurer.java:103)
    at App.createSolver(App.java:62)
    at App.main(App.java:40)

此处列出了抛出该异常的函数。该行当然是return configurer.buildSolver();。

private static Solver createSolver(){
XmlSolverConfigurer configurer = new XmlSolverConfigurer();
File file = new File("solver.xml");
FileInputStream fin = null;
try{
    fin = new FileInputStream(file);    
}
catch(IOException e){
     System.out.println("Unable to read drl");
}
configurer.configure(fin);
    //configurer.configure("/home/jesvin/dev/drools/sudoku/solver.xml");
    return configurer.buildSolver();
}

XML 的内容：

<?xml version="1.0" encoding="UTF-8"?>
<solver>
  <environmentMode>DEBUG</environmentMode>

  <solutionClass>domain.Sudoku</solutionClass>
  <planningEntityClass>domain.Digit</planningEntityClass>
  <scoreDrl>score.drl</scoreDrl>
  <scoreDefinition>
    <scoreDefinitionType>SIMPLE</scoreDefinitionType>
  </scoreDefinition>

  <termination>
    <scoreAttained>0</scoreAttained>
  </termination>
  <!--
  <constructionHeuristic>
    <constructionHeuristicType>FIRST_FIT_DECREASING</constructionHeuristicType>
    <constructionHeuristicPickEarlyType>FIRST_LAST_STEP_SCORE_EQUAL_OR_IMPROVING</constructionHeuristicPickEarlyType>
</constructionHeuristic> -->
  <constructionHeuristic>
    <constructionHeuristicType>FIRST_FIT</constructionHeuristicType>

      <moveFactoryClass>solution.RowChangeMoveFactory</moveFactoryClass>
    </selector>
    <acceptor>
      <completeSolutionTabuSize>1000</completeSolutionTabuSize>
    </acceptor>
    <forager>
      <!-- Real world problems require to use of <minimalAcceptedSelection> -->
    </forager>
  </localSearch>
</solver>

Answer 1

OP 的补充：

该问题与无意的只写属性有关。其中有 setBlockList 和 getBlocklist（getter 中的小“l”），这是一个拼写错误。 Drools 抱怨是因为它检测到两个属性，其中之一是只写的。

另一个不匹配是 isFixed 和 setFixed。它适用于内置的 boolean ，但不适用于 Boolean 对象。

我在 邮件列表帖子。

Answer 2

神秘错误消息在 5.4.0.Beta1（已发布）中得到修复：https://issues.jboss .org/browse/JBRULES-3247