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  1. Java Driver
  2. JAVA-2196

use mapReduce to get some document

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    • Icon: Task Task
    • Resolution: Done
    • Icon: Major - P3 Major - P3
    • None
    • 3.2.2
    • API
    • None
    • window7、eclipse(Mars Release (4.5.0))、jdk1.6.0_45

    Description

      I need to get a fixed number of doc by per group,when i use the method of mapReduce (class MongoCollection),it is so strange that the first doc have so many repeat keys.hope to get your answer,thank you very much.

      the example code:

              String map="function (){emit(this.domain,{_id:this._id} )}";
      		
      		String reduce="function(key,values){ var str;for(var doc in values){"
      				+ "              str=values[0];break;} return {\"docs\":str}; }";
      		MapReduceIterable<Document> mri=collect.mapReduce(map, reduce);
      		MongoCursor<Document> mc=mri.iterator();
      		int n=0;
      		while(mc.hasNext()){
      			n++;
      			Document doc=mc.next();
      			System.out.println(doc.toJson());
      		}
      
      

      the output:

      { "_id" : "a.example.com", "value" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "_id" : "d113e8d2850f0944402f3129318a9043" } } } } } } } } } } } } } }
      { "_id" : "all-femdom-movies.com", "value" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "_id" : "3238cd2caf98bf7961089e36ca33a67b" } } } } } } } } } } } } } } } } } } } }
      { "_id" : "b.example.com", "value" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "_id" : "ad8200df9d862631a8e3420c3185e210" } } } } } } }
      { "_id" : "c.example.com", "value" : { "docs" : { "docs" : { "docs" : { "docs" : { "_id" : "120eb8ade2d0665feb599748c3bd3c1d" } } } } } }
      { "_id" : "d.example.com", "value" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "_id" : "74d321593f289d25400ddfc712ddfa4b" } } } } } } } } } } } } }
      { "_id" : "e.example.com", "value" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "_id" : "c25bfbc7ea131affd9458680a40f7e18" } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } }
      { "_id" : "f.example.com", "value" : { "docs" : { "docs" : { "_id" : "9343cff09d737eee511663898cd794cc" } } } }
      { "_id" : "g.example.com", "value" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "_id" : "ef1be6af33be28752a3998bc24d515fe" } } } } } } } } } } } } } } } } } } } } } } } } } } } }
      { "_id" : "h.example.com", "value" : { "docs" : { "_id" : "1f540dd64fd45200e5ed0d51a0551546" } } }
      { "_id" : "i.example.com", "value" : { "docs" : { "docs" : { "docs" : { "_id" : "5cc7831ac9b088987f5eb48e78ff0c46" } } } } }
      { "_id" : "j.example.com", "value" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "docs" : { "_id" : "e47a5c01101395d25ff36c2be3d7af1d" } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } } }
      
      

      Edit: Sanitised the domain names in the example.

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