generics

问题 I was reading Effective Java chapter 5 about generics, in particular the items on preferring generic methods. I noticed that sometimes the type parameter(between angle brackets) in the method declaration before the return type is sometimes omitted. There are many cases like that, but for example on page 135 of the second edition: public void popAll(Collection<E> dst) { while (!isEmpty()) dst.add(pop()); } On the other hand, I have seen similar generic methods with the declaration public <E>

问题 so here's my code public void BubbleSort<T>(T[] array) where T : IComparable<T> { for (int i = 0; i < array.Length; i++) { for (int j = 1; j < array.Length; j++) { if (array[j] < array[j - 1]) { } } } } and before you shoot be down for not searching. I have searched and one of the answers here on SO said to use an icomparable interface to solve the problem. unfortunately i am not going anywhere with this error. 回答1: It looks like you're expecting the IComparable<T> constraint to allow you to

问题 so here's my code public void BubbleSort<T>(T[] array) where T : IComparable<T> { for (int i = 0; i < array.Length; i++) { for (int j = 1; j < array.Length; j++) { if (array[j] < array[j - 1]) { } } } } and before you shoot be down for not searching. I have searched and one of the answers here on SO said to use an icomparable interface to solve the problem. unfortunately i am not going anywhere with this error. 回答1: It looks like you're expecting the IComparable<T> constraint to allow you to

问题 Having the following classes: public interface Step<C extends Config> { void setConfig(C config); } and public class ValidationStep implements Step<ValidationConf> { public void setConfig(ValidationConf conf) {} // implementation } and public class ProcessStep implements Step<ProcessConf> { public void setConfig(ProcessConf conf) {} // implementation } and public interface Config { Class<? extends Step> type(); } and public class ValidationConf implements Config { public Class<? extends Step>

问题 I need to broaden my understanding of how structs are compiled when using generics. I have the following code, which works public struct TestStruct { public GenericStruct<SecondTestStruct> Header; public int TestValue; } public struct GenericStruct<T> { public int MessageSize => System.Runtime.InteropServices.Marshal.SizeOf(typeof(T)); } public struct SecondTestStruct { public int TestValue; } static void Main(string[] args) { TestStruct test = new TestStruct(); Console.WriteLine($"Size of

问题 interface Instruction { promise: Promise<unknown>, callback?: ($html: JQuery, data: unknown ) => void } const arr: Instruction[] = [ { promise: Promise.resolve({ foo: 'bar' }), callback: ($html, data) => console.log(data.foo) }, { promise: Promise.resolve({ bar: 'foo' }), callback: ($html, data) => console.log(data.bar) } ]; Given the above, I'd like TypeScript to recognise that the data parameter in the callback function is of the same type as the resolution of the Promise. If it was stand

问题 interface Instruction { promise: Promise<unknown>, callback?: ($html: JQuery, data: unknown ) => void } const arr: Instruction[] = [ { promise: Promise.resolve({ foo: 'bar' }), callback: ($html, data) => console.log(data.foo) }, { promise: Promise.resolve({ bar: 'foo' }), callback: ($html, data) => console.log(data.bar) } ]; Given the above, I'd like TypeScript to recognise that the data parameter in the callback function is of the same type as the resolution of the Promise. If it was stand

问题 interface Instruction { promise: Promise<unknown>, callback?: ($html: JQuery, data: unknown ) => void } const arr: Instruction[] = [ { promise: Promise.resolve({ foo: 'bar' }), callback: ($html, data) => console.log(data.foo) }, { promise: Promise.resolve({ bar: 'foo' }), callback: ($html, data) => console.log(data.bar) } ]; Given the above, I'd like TypeScript to recognise that the data parameter in the callback function is of the same type as the resolution of the Promise. If it was stand

问题 I want to write a generic function that takes any immutably borrowed iterable container such as an array, Vec , BTreeSet , etc. Since this function is part of a trait that I am implementing, I am not able to change the signature of it, so it's not possible to directly take an iterator as parameter and I also can't introduce any lifetime parameters to the function signature. Context I tried to implement the observer pattern in Rust. The observable and the observer look as follows: struct

问题 I want to write a generic function that takes any immutably borrowed iterable container such as an array, Vec , BTreeSet , etc. Since this function is part of a trait that I am implementing, I am not able to change the signature of it, so it's not possible to directly take an iterator as parameter and I also can't introduce any lifetime parameters to the function signature. Context I tried to implement the observer pattern in Rust. The observable and the observer look as follows: struct