Example usage for org.springframework.data.mongodb.core.aggregation ArrayOperators arrayOf

Introduction

In this page you can find the example usage for org.springframework.data.mongodb.core.aggregation ArrayOperators arrayOf.

Prototype

public static ArrayOperatorFactory arrayOf(Collection<?> values) 

Source Link

Document

Take the given Collection values AggregationExpression .

Usage

From source file:example.springdata.mongodb.aggregation.SpringBooksIntegrationTests.java

/**
 * Retrieve the number of pages per author (and divide the number of pages by the number of authors).
 *///from w  w  w . j ava2 s.  c  o  m
@Test
public void shouldRetrievePagesPerAuthor() {

    Aggregation aggregation = newAggregation( //
            match(Criteria.where("volumeInfo.authors").exists(true)), //
            replaceRoot("volumeInfo"), //
            project("authors", "pageCount") //
                    .and(ArithmeticOperators.valueOf("pageCount") //
                            .divideBy(ArrayOperators.arrayOf("authors").length()))
                    .as("pagesPerAuthor"),
            unwind("authors"), //
            group("authors") //
                    .sum("pageCount").as("totalPageCount") //
                    .sum("pagesPerAuthor").as("approxWritten"), //
            sort(Direction.DESC, "totalPageCount"));

    AggregationResults<PagesPerAuthor> result = operations.aggregate(aggregation, "books",
            PagesPerAuthor.class);

    PagesPerAuthor pagesPerAuthor = result.getMappedResults().get(0);

    assertThat(pagesPerAuthor.getAuthor()).isEqualTo("Josh Long");
    assertThat(pagesPerAuthor.getTotalPageCount()).isEqualTo(1892);
    assertThat(pagesPerAuthor.getApproxWritten()).isEqualTo(573);
}

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