I've got some JAXB generated beans which are in an hierarchical structure, eg one bean holds a list of other beans. Now I want to extend some child element and also the parent element holding the extended children. My ParentEx implements some other interface IParent which is expected to return an Collection<IChild> . My ChildEx implements IChild . Can I return a (Collection<IChi
我有一些JAXB生成的bean，它们是分层结构的，例如一个bean拥有其他bean的列表。 现在我想扩展一些子元素，也是扩展子元素的父元素。 我的ParentEx实现了一些其他接口IParent ，预计它将返回一个Collection<IChild> 。 我的ChildEx实现IChild 。 当super.getChild()返回List<Child>时，我可以返回一个(Collection<IChild>)super.getChild()吗？ 还是有更好的方法呢？ Child和Parent是JAXB生成的bean
I have a Java Swing application wich spawns child dialogs with text controls. And the problem is that when you change keyboard layout in child dialog, it changes back right after the dialog is closed. What I need is the keboard layout to stay after being switched whether it was switched in the main frame or in a child frame. Here is a SSCCE that illustrates the problem: import javax.swing.*
我有一个Java Swing应用程序，它产生了带有文本控件的子对话框。 问题是，当您更改子对话框中的键盘布局时，它将在对话框关闭后立即返回。 我需要的是keboard布局在切换后保留，无论它是在主框架还是在子框架中切换。 这是一个说明问题的SSCCE： import javax.swing.*; import java.awt.*; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; public class InheritInputContext { public sta
Hello I have 2 lists that contains the same objects. I would like to perform any operation like intercesct, union, distinct by using predicate because I am unable to use equals to comparision. Example: class Car{ public String id; public String color; public int hashcode(){ //id field is used for hashcode } public boolean equals(){ //id field is used for equals } } Now I
你好我有2个包含相同对象的列表。 我想通过使用谓词来执行像intercesct，union和distinct这样的操作，因为我无法使用equals来进行比较。 例： class Car{ public String id; public String color; public int hashcode(){ //id field is used for hashcode } public boolean equals(){ //id field is used for equals } } 现在我有两个汽车列表。 我需要在此列表中查找重复项，但不能仅通过颜色来查找
I need to swap two variables without both XOR and arithmetic operations. All I can use are bitwise operations like ~, &, |, <<, >>, etc. I understand the XOR approach, but can't figure out the other way around this.. EDIT: Temporary variables are not allowed either. Since XOR is a combination of ANDs and NOTs, all you need to do is implementing it in Java: static int n
我需要在没有XOR和算术运算的情况下交换两个变量。 我所能使用的只是像〜，＆，|，<<，>>等按位运算。 我了解XOR方法，但无法找出解决方法。 编辑：临时变量也不允许。 由于XOR是AND和NOT的组合，所以您只需要在Java中实现它即可： static int nand(int a, int b) { return ~(a & b); } static int xor(int a, int b) { return nand(nand(a, nand(a, b)), nand(b, nand(a, b))); } 有了这个实
I am currently writing a series of tests in JUnit. I need to automatically export the results as XML. I was reading that the best way of doing this is by extending the RunListener class and writing the XML that way. Below is a sample of what I have done so far, but I am struggling with how to extract information on each test that has been run. The 'Description' class doesn't seem
我目前正在JUnit中编写一系列测试。 我需要自动将结果导出为XML。 我在读这样做的最好方法是通过扩展RunListener类并以这种方式编写XML。 下面是我迄今为止所做的一些示例，但我正在努力解决已经运行的每个测试的信息。 '描述'类似乎没有任何有用的获取方法，我觉得我可能会这样做是错误的。 有人可以协助如何从描述中获得有用的信息（例如，测试通过/失败，测试持续时间，测试名称等）还是给我提供一些我应该做什
Given this C++ Code: void LoadData(char** myVar) { std:: string str("[Really Long String Here]"); unsigned int size = str.length() + 1; *myVar = new char[size]; strncpy(*myVar, str.c_str(), size); } And this JNA Java: Pointer myVar = new Memory(Pointer.SIZE); this.Lib.LoadData(myVar); this.someVar = myVar.getPointer(0).getString(0); I'm having memory leaks, as I understand
鉴于这个C ++代码： void LoadData(char** myVar) { std:: string str("[Really Long String Here]"); unsigned int size = str.length() + 1; *myVar = new char[size]; strncpy(*myVar, str.c_str(), size); } 而这个JNA Java： Pointer myVar = new Memory(Pointer.SIZE); this.Lib.LoadData(myVar); this.someVar = myVar.getPointer(0).getString(0); 我有内存泄漏，据我了解，getPointer（0）应该创建
Problem summary: I would like to pass a class with a type parameter (such as ArrayList<SomeClass> , for example) to a generic method as a type parameter. Let's say I have a method: public static <T> T getGenericObjectFromJson(String json, Class<T> genericType){ // details unimportant, basically returns an object of specified type return JsonParser.from
问题摘要：我想将类型参数（例如ArrayList<SomeClass> ）的类作为类型参数传递给泛型方法。 假设我有一个方法： public static <T> T getGenericObjectFromJson(String json, Class<T> genericType){ // details unimportant, basically returns an object of specified type return JsonParser.fromJson(json, genericType); } 当然，这种方法对于任何一类课程都可以很好地工作
Java enums are great. So are generics. Of course we all know the limitations of the latter because of type erasure. But there is one thing I don't understand, Why can't I create an enum like this: public enum MyEnum<T> { LITERAL1<String>, LITERAL2<Integer>, LITERAL3<Object>; } This generic type parameter <T> in turn could then be useful in va
Java枚举是伟大的。 泛型也是如此。 当然，由于类型擦除，我们都知道后者的局限性。 但有一件事我不明白，为什么我不能创建这样的枚举： public enum MyEnum<T> { LITERAL1<String>, LITERAL2<Integer>, LITERAL3<Object>; } 这个泛型类型参数<T>反过来可以在各个地方有用。 设想一个方法的泛型类型参数： public <T> T getValue(MyEnum<T> param); 或者甚至在枚
How can I achieve this? public class GenericClass<T> { public Type getMyType() { //How do I return the type of T? } } Everything I have tried so far always returns type Object rather than the specific type used. As others mentioned, it's only possible via reflection in certain circumstances. If you really need the type, this is the usual (type-safe) workaround
我怎样才能做到这一点？ public class GenericClass<T> { public Type getMyType() { //How do I return the type of T? } } 到目前为止我尝试过的所有东西总是返回Object类型而不是使用的特定类型。 正如其他人所提到的，只有在某些情况下才可以反思。 如果您真的需要这种类型，这是通常的（类型安全的）解决方法模式： public class GenericClass<T> { private final Class<T&
I am trying to decide whether I should use App-engine Search API or Datastore for an App-engine Connected Android Project. The only distinction that the google documentation makes is ... an index search can find no more than 10,000 matching documents. The App Engine Datastore may be more appropriate for applications that need to retrieve very large result sets. Given that I am already very
我正在尝试决定是否应将App-engine Search API或Datastore用于App-engine Connected Android项目。 谷歌文档的唯一区别是 ...索引搜索可以找到不超过10,000个匹配文档。 App Engine数据存储可能更适合需要检索非常大的结果集的应用程序。 鉴于我已经非常熟悉数据存储：假设我不需要10,000个结果，是否有人请帮助我？ 是否有任何优势，以使用Search API与使用数据存储为我的查询（根据上面的报价，这似乎是合理使用一个或