How do I merge a map list into a map?

Can you help me solve Java streams?

As you can see from the title, I need to merge list < map < string, map < string, genuineness > > to map < string, genuineness > >

The list is represented as list < map < string, genuineness > > > and looks like:

[  
   {  
      "USER_1":{  
         "APP_1":{  
            "total":1,"totalGenuine":1,"totalDevelopment":1
         }
      },"USER_2":{  
         "APP_1":{  
            "total":1,"totalDevelopment":1
         },"APP_2":{  
            "total":2,"totalGenuine":2,"totalDevelopment":2
         }
      }
   },{  
      "USER_1":{  
         "APP_1":{  
            "total":1,"totalDevelopment":2
         }
      }
   }
]

So, as you can see, duplicate keys can be everywhere My goal is to combine them into map < < string, genuineness > > by merging authenticity Merging authenticity simply means returning a new object with the sum of total, totalgenius, and totaldevelopment

This is my implementation failure:

final Map<String,Map<String,Genuineness>> map = taskHandles.stream().map(this::mapTaskHandle)
                .flatMap(m -> m.entrySet().stream()).collect(
                        Collectors.toMap(Map.Entry::getKey,e -> e.getValue().entrySet().stream()
                                .collect(
                                        Collectors.toMap(Map.Entry::getKey,g -> new Genuineness(g.getValue().getTotal(),g.getValue().getTotalGenuine(),g.getValue().getTotalDevelopment()),(g1,g2) -> new Genuineness(g1.getTotal() + g2.getTotal(),g1.getTotalGenuine() + g2.getTotalGenuine(),g1.getTotalDevelopment() + g2.getTotalGenuine()
                                                )
                                        )
                                )
                        )
                );

It failed with the message:

java.lang.IllegalStateException: Duplicate key {TEST_33_33_APP_1=live.attach.billing.domain.model.billing.Genuineness@951b6fe}

So, it seems that in my implementation, I have pointed out how to combine internal maps, but I don't know what to do without merging the values of external maps

I appreciate your help very much Thank you first!

Update: expected production:

{  
      "USER_1":{  
         "APP_1":{  
            "total":2,"totalDevelopment":2
         }
      },"USER_2":{  
         "APP_1":{  
            "total":2,"totalDevelopment":2
         },"APP_2":{  
            "total":4,"totalGenuine":4,"totalDevelopment":4
         }
      }
   }

Solution

To be honest, this is a terrible data structure, and it is difficult for the maintainer of this code to find the problem

You should take a step back and consider refactoring the code. You can solve the missing part by using the following merge function in the outermost tomap:

(l,r) -> {
      r.forEach((k,v) -> l.merge(k,v,(bi,bii) -> new Genuineness(bi.getTotal() + bii.getTotal(),bi.getTotalGenuine() + bii.getTotalGenuine(),bi.getTotalDevelopment() + bii.getTotalGenuine())));
       return l;
}

Full code:

taskHandles.stream().map(this::mapTaskHandle)
                .flatMap(m -> m.entrySet().stream()).collect(
                        Collectors.toMap(Map.Entry::getKey,g1.getTotalDevelopment() + g2.getTotalGenuine()
                                                )
                                        )
                                ),(l,r) -> {
                                  r.forEach((k,bi.getTotalDevelopment() + bii.getTotalGenuine())));
                                  return l;
                                }

                        )
                );

Ideone