java - Set 中的 GenericsAdd (capture ) 无法应用于 (ConstraintViolation)

Question

我有以下代码:

UniqueConstraintViolation violation = new UniqueConstraintViolationImpl();
Set<? extends javax.validation.ConstraintViolation> violations = new HashSet<UniqueConstraintViolation>();
violations.add(violation);
throw new javax.validation.ConstraintViolationException(violations);

其中 UniqueConstraintViolation 是接口(interface)扩展 javax.validation.ConstraintViolationUniqueConstraintViolationImpl 是实现 UniqueConstraintViolation 的类

编译时出现以下错误

java:42: error: no suitable method found for add(UniqueConstraintViolation) violations.add(violation); ^ method Collection.add(CAP#1) is not applicable (argument mismatch; UniqueConstraintViolation cannot be converted to CAP#1 ) method Set.add(CAP#1) is not applicable (argument mismatch; UniqueConstraintViolation cannot be converted to CAP#1 ) where CAP#1 is a fresh type-variable: CAP#1 extends ConstraintViolation from capture of ? extends ConstraintViolation C:\workspace\zcts-travel\crud-rest\src\main\java\ru\zcts\crud\AbstractResource.java:43: error: incompatible types: Set cannot be converted to Set> throw new javax.validation.ConstraintViolationException(violations);

                                                                ^   where CAP#1 is a fresh type-variable:
CAP#1 extends ConstraintViolation from capture of ? extends ConstraintViolation

我只想将我自己的 javax.validation.ConstraintViolation 实现传入 javax.validation.ConstraintViolationException 构造函数中。我该怎么做？

Answer 1

所以有你的限制:

interface UniqueConstraintViolation extends ConstraintViolation<YourClass> {

}

public class UniqueConstraintViolationImpl implements UniqueConstraintViolation {
    /* your impl here */
}

这将编译:

UniqueConstraintViolation violation = new UniqueConstraintViolationImpl();

Set<UniqueConstraintViolation> violations = new HashSet<UniqueConstraintViolation>();
violations.add(violation);
throw new ConstraintViolationException(violations);