转换Collection< MyType>收集<对象> [英] convert Collection<MyType> to Collection<Object>

问题描述

  public UniqueField（Collection< Object> items）{
 this.items =物品; 
} 
  

Collection< Object> 是我可以使用集合< OtherType> 。

在做：

 集合< OtherType> collection = ... 
 UniqueField（collection）; 
  

我得到无效参数的编译错误。如何解决这个问题？

解决方案

您必须使用它而不是

  public UniqueField（Collection< ;? extends Object> items）{
 this.items = items; 
} 
  

或？因为它等于？extends Object

  public UniqueField（Collection<> items）{
 this .items =物品; 
} 
  

你可以看到这里为原因

I have a class with the following constructor:

public UniqueField(Collection<Object> items) {
      this.items=items;
}

The idea behind the Collection<Object> is that I would be able to use Collection<OtherType>.

When doing:

Collection<OtherType> collection=... 
new UniqueField(collection);

I getting a compile error of invalid argument. How can I fix this?

解决方案

You have to use this instead

public UniqueField(Collection<? extends Object> items) {
      this.items=items;
}

or ? because it is equal to "? extends Object"

public UniqueField(Collection<?> items) {
      this.items=items;
}

You can see here for the reason

这篇关于转换Collection< MyType>收集<对象>的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！