在java中创建一个静态通用工厂？

Question

我遇到了这个getInstance方法的问题,我尝试的任何方式:

Cannot make a static reference to the non-static type T.

我怎么能做这个工作？任何代码审查也将是一个很好的帮助.我检查了几个相关的帖子,但这似乎是一个特殊的情况.

• java参数化通用静态工厂
• Java Generics WildCard:<？extends Number> vs <T extends Number>
• static <T extends Number&Comparable <？超级号码>>

我的代码:

public class Data<Template>
{
    private Template[] data;
    private int id;

    public Data(Template[] data)
    {
        this.data = data;
        id = Arrays.hashCode(data);
        log();
    }

    public Template[] getData()
    {
        return data;
    }

    public Integer getId()
    {
        return id;
    }

    private void log()
    {
        System.out.println(this.toString());
    }

    @Override
    public String toString()
    {
        StringBuilder tString = new StringBuilder();
        tString.append(id + ":");
        for (int i = 0; i < data.length; i++)
        {
            tString.append(data[i] + " ");
        }
        return tString.toString();
    }
}

public class Store<T>
{
    private Queue<Data<T>> queue;
    private ConcurrentHashMap<Integer, Data<T>> inProgress;
    private List<T> results;
    private static Store instance = null;

    private Store()
    {
        queue = new ConcurrentLinkedQueue<Data<T>>();
        inProgress = new ConcurrentHashMap<Integer, Data<T>>(16, 0.9f, 1);
        results = new ArrayList<>();
    }

    public void addToStore(Data<T> elment)
    {
        queue.offer(elment);
    }

    public Data<T> getNextTask()
    {
        Data<T> element = queue.poll();
        inProgress.put(element.getId(), element);
        return element;
    }

    public void taskFinishedSuccessfully(Integer id, T result)
    {
        inProgress.remove(id);
        results.add(result);
    }

    public List<T> getResults()
    {
        return results;
    }

    public static Store getInstance(Class<T> type)
    {
        if (instance == null)
        {
            if (type instanceof Integer)
            {
                instance = new Store<Integer>();
            }

            if (type instanceof Float)
            {
                instance = new Store<Float>();
            }

            if (type instanceof Double)
            {
                instance = new Store<Double>();
            }
        }
        return instance;
    }
}

Answer 1

目前尚不清楚为什么你不只是写作

public static <T> Store<T> getInstance() {
  return new Store<T>();
}