Question

我正在尝试将对象添加到arraylist中。这些对象都不包含任何静态字段或静态方法，但是当更新arraylist时，所有元素都会包含“＆＃39; new＆＃39;值。此外，每次循环时都会创建一个新实例，所以我不认为我一直在添加相同的对象。

ArrayList<Integer> rewards = new ArrayList<Integer>(); 
ArrayList<ArrayList<Route>> neighbours = new ArrayList<ArrayList<Route>>();

for(int i=0; i<10; i++)
{
    Generate1Neighbour neighbour = new Generate1Neighbour(testDataFile,amp2Solution,randomGenerator,i);
    System.out.println("Generated neighbour (Reward " + getSolutionReward(neighbour.solution)+ "): " + neighbour.solution.toString());
    rewards.add(getSolutionReward(neighbour.solution));
    neighbours.add(neighbour.solution);
}

testDataFile和amp2Solution在循环期间保持不变。

当我打印生成的邻居时，我可以看到在每次循环迭代中创建了一个不同的邻居。然而，在此循环之后，邻居包含10个相同的元素。

奖励确实包含10个不同的值。在Generate1Neighbour类中，没有字段或方法是静态的。

此处，解决方案定义如下：

public ArrayList<Route> solution;

在Generate1Neighbour类中，使用了多种方法来更新解决方案。

我可以做错什么？

编辑： getSolutionReward方法如下：

public static int getSolutionReward(ArrayList<Route> solution)
{
    int totalReward = 0;
    for(Route route : solution)
    {
        totalReward += route.getReward();
    }
    return totalReward;
}

amp2solution是一个ArrayList。在Generate1Neighbour的构造函数中，变量＆＃39;解决方案＆＃39;设置为等于传递给构造函数的amp2solution。这个解决方案＆＃39;变量在Generate1Neighbour类中的许多方法中更新。

Generate1Neighbour的构造函数如下：

public Generate1Neighbour(DataFile testDataFile, ArrayList<Route> Sol, Random randomGen, int q_tabu) throws IOException
{
    System.out.println("Starting Tabu procedure ");
    neighbourhoodSize = "Small";
    solution = Sol;
    S_Comp = new ArrayList<MyNodesData>();
    startPoint = testDataFile.getStartPoint();
    finishPoint = testDataFile.getFinishPoint();
    maxDuration = testDataFile.getMaxDuration();
    randomGenerator = randomGen;
    toRemoveRVI = 3;

    //----------------(A) : Initialization---------------- 
    parameterSet = new ParameterSet(neighbourhoodSize, testDataFile);
    generateSComp(testDataFile, solution, S_Comp);

    //---------Generating neighborhood solutions---------   //Generate number of neighborhood solutions (feasible and 
                                                            //infeasible) to the current solution, based on current
                                                            //tabu parameters.

    routeNumbers = twoRandomTours(solution, randomGenerator);   
    r1 = solution.get(routeNumbers[0]);
    r2 = solution.get(routeNumbers[1]);         

    solution = insertInS(solution, routeNumbers, maxDuration, startPoint, finishPoint, S_Comp, SE, successfulInsert);           
    if(!successfulInsert)
    {
        solution = exchangeWithSComp(solution, parameterSet, routeNumbers, maxDuration, S_Comp, randomGenerator);       
        new RoutesToXLS(solution, "Tabu3");
    }
    else
    {
        new RoutesToXLS(solution, "Tabu2");
    }

    //----------------(B) : Improvement---------------- 

    solution = balance(solution,r1,r2);     
    if(!successfulBalance)
    { 
        exchangeBetweenTours(r1,r2);                    
        new RoutesToXLS(solution, "Tabu5");
    }
    else
    {
        new RoutesToXLS(solution, "Tabu4");
    }
    if(q_tabu % parameterSet.getChi() == 0 && q_tabu!=0)        
    {   
        solution = RVI(solution, routeNumbers, maxDuration, startPoint, finishPoint, S_Comp, SE, randomGenerator, toRemoveRVI, successfulInsert);
        new RoutesToXLS(solution,"AfterRVI");
    }
}

当没有字段是静态的时，为什么我的arraylist包含n个相同的元素？

0 个答案: