File APIs for Java Developers
Manipulate DOC, XLS, PPT, PDF and many others from your application.
http://aspose.com/file-tools
The moose likes MongoDB and the fly likes Mongo aggregation framework Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login


Win a copy of OCM Java EE 6 Enterprise Architect Exam Guide this week in the OCMJEA forum!
JavaRanch » Java Forums » Databases » MongoDB
Bookmark "Mongo aggregation framework" Watch "Mongo aggregation framework" New topic
Author

Mongo aggregation framework

vinny kapoor
Greenhorn

Joined: Apr 05, 2008
Posts: 13
I wanted to write down my first query using spring's mongo aggregation framework. The query is basically to group by 'field' and then to count the number of occurences.

Something similar to

Select state, count(state)
from <table>
group by (state)

Corresponding query using mongo spring's framework using java:

TypedAggregation<Ticket> aggregation = newAggregation(Ticket.class, group("state").count().as("count"),
project("state").and("count").previousOperation());

AggregationResults<cheese> results = springMongoManager.getDao().aggregate(aggregation, cheese.class);
List<cheese> mappedResults = results.getMappedResults();


where

class cheese {
String state;
long count;
}


The above query clearly is not working.

Any help will be appreciated.
 
jQuery in Action, 2nd edition
 
subject: Mongo aggregation framework