关于lambda：java以下枚举中的{{}}和 – >是什么

java What is {{ }} and -> in the following enum

本问题已经有最佳答案，请猛点这里访问。

我有一个非常基本的疑问！
{{}}和 - >是什么意思，它对于以下枚举意味着什么？

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

public enum BuyUsedFeatureFilters implements FeatureFilter {

BuyUsedContext {{
requestProperty =
req -> isBuyUsedContext(req);
}};

RequestProperty<Boolean> requestProperty;
PropertyCondition defaultCondition = PropertyCondition.IGNORE;

@Override
public RequestProperty<Boolean> requestProperty() {
return requestProperty;
}

private static boolean isBuyUsedContext(RequestContext requestContext){
String buyUsedParam = requestContext.getParameters().get("buyUsedParam");

if (StringUtils.equals(buyUsedParam,"buyUsed")) {
return true;
}
return false;
}
}