我见过如下所示的方法:
protected <T extends ABC> T save( T Acd, boolean en) {
它有什么作用？在Java中调用的这些类型的方法声明是什么？
我有一个接口,其声明如下:
/**
* @param T - the type of entity.
* @param C - the type of entity container will be returned.
*/
public interface FindByNamedQuery<T extends Serializable, C extends Collection<T>> extends Command {
C executeNamedQuery(String namedQuery);
}
我想知道我是否可以(应该)打破Java命名约定来执行此操作:
public interface FindByNamedQuery<ENTITY_TYPE extends Serializable, RETURNED_CONTAINER extends Collection<ENTITY_TYPE>> extends Command {
RETURNED_CONTAINER executeNamedQuery(String namedQuery);
}
我有一个哈希地图,我想复制其他用途.但每当我复制并重复使用它时,它也会改变原来的.这是为什么？
do {
Map<Integer, Map<String, Object>> map1 = originalMap;
//at the second iteration originalMap is the same as map1 of the last iteration,
//eventhough the change was nog accepted;
//do something with map1 (change value);
if(change is accepted) {
originalMap = map1;
}
} while(iteration < 10);
提前致谢
public static <Integer,String, Schedule>Map<Integer, Map<String, Schedule>> deepCopy(Map<Integer, Map<String, Schedule>> original) {
Map<Integer, Map<String, Schedule>> copy = new HashMap<Integer, Map<String, Schedule>>();
for (Map.Entry<Integer, Map<String, Schedule>> entry : original.entrySet()) {
copy.put(entry.getKey(), deepCopy2(entry.getValue()));
}
return …我正在努力做这项工作:
public abstract class MapperFactory<M extends TaskMapper<? extends Message, ? extends Message, ? extends TaskForm>> {
public static <M extends TaskMapper<? extends Message, ? extends Message, ? extends TaskForm>> MapperFactory<M> getMapperFactory(Message msgIn, Message msgOut) {
if (msgIn.isMyMapper())
return new MyTaskMapperFactory();
throw new IllegalStateException("Mapper not found!");
}
public abstract TaskMapper<? extends Message, ? extends Message, ? extends TaskForm> getTaskMapper();
public static class MyTaskMapperFactory extends MapperFactory<MyTaskMapper> {
@Override
public TaskMapper<? extends Message, ? extends Message, ? extends TaskForm> getTaskMapper() {
return new …什么是AnyTypejava。我什么时候应该使用它。例如，TestRpn<AnyType extends Comparable<AnyType>>在此代码段中，什么是AnyType，以及它可以拥有什么样的数据（例如Integer，Boolean）