Examples with ProjectionOperation org.springframework.data.mongodb.core.aggregation.ProjectionOperation used on opensource projects

Example 1 with ProjectionOperation

use of org.springframework.data.mongodb.core.aggregation.ProjectionOperation in project tutorials by eugenp.

the class ZipsAggregationLiveTest method whenStateWithLowestAvgCityPopIsND_theSuccess.

@Test
public void whenStateWithLowestAvgCityPopIsND_theSuccess() {
    GroupOperation sumTotalCityPop = group("state", "city").sum("pop").as("cityPop");
    GroupOperation averageStatePop = group("_id.state").avg("cityPop").as("avgCityPop");
    SortOperation sortByAvgPopAsc = sort(new Sort(Direction.ASC, "avgCityPop"));
    ProjectionOperation projectToMatchModel = project().andExpression("_id").as("state").andExpression("avgCityPop").as("statePop");
    LimitOperation limitToOnlyFirstDoc = limit(1);
    Aggregation aggregation = newAggregation(sumTotalCityPop, averageStatePop, sortByAvgPopAsc, limitToOnlyFirstDoc, projectToMatchModel);
    AggregationResults<StatePopulation> result = mongoTemplate.aggregate(aggregation, "zips", StatePopulation.class);
    StatePopulation smallestState = result.getUniqueMappedResult();
    assertEquals("ND", smallestState.getState());
    assertTrue(smallestState.getStatePop().equals(1645));
}