java - Spring Data Mongodb - repository for collection with different types -

-

i have mongo collection may contain 3 types of entities map java types:

  • node
  • leaftype1
  • leaftype2

collection ment store tree-like structure using dbrefs of child nodes in parent entry.

i didn't find information subject in spring reference documentation i'm asking here: there way use repository mechanism work collection may contain different types of objects?

declaring several repositories different types in 1 collection seems not idea because struggle situations when queried object not of expected type , creating 1 repository abstract class possible types inherrit doesn't seems work.

to illustrate mean:

/**  * seems not safe  */ public interface noderepository extends mongorepository<node, string> { } public interface leaftype1repository extends mongorepository<leaftype1, string> { } public interface leaftype2repository extends mongorepository<leaftype2, string> { }  /**  * doesn't work @  */ public interface mycollectionrepository extends mongorepository<abstractmycollectionnode, string> { }

if node\leaftype1\leaftype2 sub-classes of abstractmycollectionnode, things easy. declare repository write:

public interface mycollectionrepository extends mongorepository<abstractmycollectionnode, string> { }

we have done in project, , works good. spring data add property named '_class' documents in mongodb collection, can finger out class instantiate.

documents stored in 1 collection may have similarity, maybe can extract generic class them.

here code copied 1 of our projects:

entity:

public abstract class document {     private string id;      public string getid() {         return id;     }      public void setid(string id) {         this.id = id;     }     .... 
public class webclipdocument extends document {     private string digest;     ...

repository:

public interface documentdao extends mongorepository<document, string>{ ...

and, if documents in mongodb collection not have "_class" property. can use converter:

when storing , querying objects convenient have mongoconverter instance handle mapping of java types dbobjects. however, may want `mongoconverter’s of work allow selectively handle conversion particular type or optimize performance.


Comments

Post a Comment

Popular posts from this blog

ruby on rails - RuntimeError: Circular dependency detected while autoloading constant - ActiveAdmin.register Role -

-
i using activeadmin , have file doing this: activeadmin.register role something--- end however, server gives me error: runtimeerror: circular dependency detected while autoloading constant role /library/ruby/gems/2.0.0/gems/activesupport-4.0.10/lib/active_support/dependencies.rb:461:in `load_missing_constant' /library/ruby/gems/2.0.0/gems/activesupport-4.0.10/lib/active_support/dependencies.rb:184:in `const_missing' ~/desktop/boxfox/app/admin/role.rb:1:in `<top (required)>' /library/ruby/gems/2.0.0/gems/activesupport-4.0.10/lib/active_support/dependencies.rb:424:in `load' /library/ruby/gems/2.0.0/gems/activesupport-4.0.10/lib/active_support/dependencies.rb:424:in `block in load_file' /library/ruby/gems/2.0.0/gems/activesupport-4.0.10/lib/active_support/dependencies.rb:616:in `new_constants_in' /library/ruby/gems/2.0.0/gems/activesupport-4.0.10/lib/active_support/dependencies.rb:423:in `load_file' /library/ruby/gems/2.0.0/gems/activesuppor...
Read more

c++ - OpenMP unpredictable overhead -

-
i have simple openmp code runs 4 empty threads , reports time: #include "omp.h" #include <sys/time.h> #include <cstdio> double start_time; void process_thread() { } int main(){ struct timeval tv; gettimeofday(&tv, null); start_time = 1000*((double)tv.tv_sec + 1e-6*(double)tv.tv_usec); printf("beginning time: %.3fms ",start_time-start_time); #pragma omp parallel schedule(static,1) for(int i=0;i<4;i++) process_thread(); gettimeofday(&tv, null); double cur_time = 1000*((double)tv.tv_sec + 1e-6*(double)tv.tv_usec); printf("finishing time: %.3fms\n\n",cur_time-start_time); } without openmp running time small , consistent: beginning time: 0.000ms finishing time: 0.050ms beginning time: 0.000ms finishing time: 0.050ms beginning time: 0.000ms finishing time: 0.049ms beginning time: 0.000ms finishing time: 0.049ms beginning time: 0.000ms finishing time: 0.050ms beginnin...
Read more

django rest framework - DRF 3.0: UniqueTogetherValidator with a read-only field -

-
in process of upgrading django rest framework 3.0 2.4.4 , want have read-only user field, failing because 'user' being required uniquetogethervalidator (i think) i have model (excuse typos, simplified , code works fine irl): class examplemodel(models.model): some_attr = models.positivesmallintegerfield() other_attr = models.positivesmallintegerfield() user = models.foreignkey(user) class meta: unique_together = ('some_attr', 'other_attr', 'user') viewset: class exampleviewset(viewsets.modelviewset): queryset = examplemodel.objects.all() serializer_class = exampleserializer def perform_create(self, serializer): serializer.save(user=self.request.user) def perform_update(self, serializer): serializer.save(user=self.request.user) serializer: class exampleserializer(serializers.modelserializer): user = userserializer(read_only=true) class meta: model = examplemodel n...
Read more