Java函数接口自动将第一个参数指定为类?
函数接口定义了采用2个参数的方法MyFunc,但当此方法在HighTemp类中实现时,出于某种原因,它只有1个参数,并且使用Java函数接口自动将第一个参数指定为类?,java,lambda,functional-programming,Java,Lambda,Functional Programming,函数接口定义了采用2个参数的方法MyFunc,但当此方法在HighTemp类中实现时,出于某种原因,它只有1个参数,并且使用f.func(vals[i],v)调用它,该函数如何调用此方法布尔sameTemp(HighTemp ht2),我错过了什么 interface MyFunc<T> { boolean func(T v1, T v2); } class HighTemp { private int hTemp; HighTemp(int ht) {
f.func(vals[i],v)
调用它,该函数如何调用此方法布尔sameTemp(HighTemp ht2)
,我错过了什么
interface MyFunc<T> {
boolean func(T v1, T v2);
}
class HighTemp {
private int hTemp;
HighTemp(int ht) { hTemp = ht; }
boolean sameTemp(HighTemp ht2) {
return hTemp == ht2.hTemp;
}
boolean lessThanTemp(HighTemp ht2) {
return hTemp < ht2.hTemp;
}
}
public class InstanceMethObjectRefDemo {
static<T> int Counter(T[] vals, MyFunc<T> f, T v) {
int count = 0;
for (int i = 0; i < vals.length; i++)
if (f.func(vals[i], v)) count++;
return count;
}
public static void main(String[] args) {
int count;
HighTemp[] weekDayHighs = {
new HighTemp(89), new HighTemp(82),
new HighTemp(90), new HighTemp(89),
new HighTemp(89), new HighTemp(91),
new HighTemp(84), new HighTemp(83)
};
count = Counter(weekDayHighs, HighTemp::sameTemp, new HighTemp(89));
System.out.println(count + " days had a high of 89");
HighTemp[] weekDayHighs2 = {
new HighTemp(32), new HighTemp(12),
new HighTemp(24), new HighTemp(19),
new HighTemp(18), new HighTemp(12),
new HighTemp(-1), new HighTemp(13)
};
count = Counter(weekDayHighs2, HighTemp::sameTemp, new HighTemp(12));
System.out.println(count + " days had a high of 12");
count = Counter(weekDayHighs, HighTemp::lessThanTemp, new HighTemp(89));
System.out.println(count + " days had a high less than 89");
count = Counter(weekDayHighs2, HighTemp::lessThanTemp, new HighTemp(19));
System.out.println(count + " days had a high of less then 19");
}
}
接口MyFunc{
布尔函数(T v1,T v2);
}
类高温{
私有int hTemp;
高温(int-ht){hTemp=ht;}
布尔sameTemp(高温ht2){
返回hTemp==ht2.hTemp;
}
布尔lessThanTemp(高温ht2){
返回hTemp
高温::sameTemp相当于:
(HighTemp t1, HighTemp t2) -> t1.sameTemp(t2);
HighTemp::sameTemp
相当于:
(HighTemp t1, HighTemp t2) -> t1.sameTemp(t2);
对不起,我不太清楚你在问什么。你能重新措辞吗?是的,但是“boolean sameTemp(HighTemp ht2)”需要1个参数,用2个参数调用此方法如何正确?可能会问为什么方法引用在构造函数中工作?你能编辑你的代码使
计数器大写吗?因为这可能会使人们比你想象的更难阅读。请具体说明你认为哪些行/表达有问题。对不起,我不完全清楚你在问什么。你能重新措辞吗?是的,但是“boolean sameTemp(HighTemp ht2)”需要1个参数,用2个参数调用此方法如何正确?可能会问为什么方法引用在构造函数中工作?你能编辑你的代码使计数器大写吗?因为这可能会使人们比你想象的更难阅读。并明确哪些行/表达式是您认为可能存在问题的