如何检查TreeMap是否是Java中另一个TreeMap的子图

Question

New to Java 8, and am unable to figure this one out. I have two maps of type TreeMap<Long, Integer> , one is called patternMap and the other answerMap .

patternMap is hardcoded to look for a particular pattern of key-value pairs, so there are many patternMap 's, and their size is always less than or equal to answerMap . I would like to check which patternMap s are a match in answerMap , and I mean I need exact match on key and value both, not just one.

I'm unable to use the submap method, because patternMap may not have a contiguous range of keys. The obvious way is to walk through the patternMap and check each Map.Entry object with equals method. However, I have many patternMap 's to check against a particular answerMap , so I'm curious to know if there is a better way, probably using lambdas/streams. I also cannot modify the answerMap or the patternMap , so this has to be a non-mutating function. I use TreeMap 's because the ordering is important for the application.

There is no code here because I haven't found a way to do this, but pseudo-code would look like this:

for every patternMap in the Collection {
   if answerMap contains patternMap, make a note
}

EDIT: Here are some definitions(this isn't working code, but hopefully makes question clearer:

 private static final TreeMap<Long, Integer> patternMap1;
 private static final TreeMap<Long, Integer> patternMap2;
 private static final ArrayList<TreeMap> listOfPatternMaps;
 private TreeMap<Long, Integer> answerMap;

  private Set<TreeMap<Long, Integer>> findPatterns(TreeMap answerMap) {
       this.answerMap = answerMap;
       for(patternMap : listOfPatternMaps) {
           if answerMap contains patternMap {
              make a note
           }
       } 
       return setOfMatchedPatterns;
  }

Answer 1

这应该可以解决问题：

answerMap.entrySet().containsAll(patternMap.entrySet())