Java:如何使用谷歌的HashBiMap？

Question

键是一个文件和一个词。该文件给出了文件中的所有单词。这个词给出了所有有这个词的文件。我不确定域和共同域部分。我希望 K 属于 <String> 类型V 的类型为 <HashSet<FileObject>> .

    public HashBiMap<K<String>,V<HashSet<FileObject>>> wordToFiles 
            = new HashBiMap<K<String>,V<HashSet<FileObject>>>();

    public HashBiMap<K<String>,V<HashSet<FileObject>>> fileToWords 
            = new HashBiMap<K<String>,V<HashSet<FileObject>>>();

Google's HashBiMap.

Answer 1

改成

public HashBiMap<String,HashSet<FileObject>> wordToFiles = HashBiMap.create ();

但是看起来还是很奇怪。我认为你应该使用另一个集合。来自 BiMap 文档(HashBiMap impelements BiMap):

A bimap (or "bidirectional map") is a map that preserves the uniqueness of its values as well as that of its keys. This constraint enables bimaps to support an "inverse view", which is another bimap containing the same entries as this bimap but with reversed keys and values.

我不知道您要解决的问题，但在查看您的代码后，我可以建议考虑使用 Multimaps。从它的文档:

A collection similar to a Map, but which may associate multiple values with a single key. If you call put(K, V) twice, with the same key but different values, the multimap contains mappings from the key to both values.

例如，你可以这样做:

Multimap<String, FileObject> wordToFiles = HashMultimap.create();
wordToFiles.put("first", somefile);
wordToFiles.put("first", anotherfile);
for (FileObject file : wordToFiles.get("first"){
   doSomethingWithFile (file);
}