java - Google Multimap 中的通用

Question

你有理由吗 MultiMap是不是完全通用？

containsEntry(Object key, Object value)
containsKey(Object key)
remove(Object key, Object value)
removeAll(Object key) 

Answer 1

看this answer Guava 的 Multimap 也是如此。另外，您可能需要阅读 Kevin Bourrillion's blog entry (他是 Guava lead dev)解释了同样的问题(注意 add 使用通用类型 E):

The real difference is that add() can cause "damage" to the collection when called with the wrong type, and contains() and remove() cannot.

Uniformly, methods of the Java Collections Framework (and the Google Collections Library too) never restrict the types of their parameters except when it's necessary to prevent the collection from getting broken.