Package dev.morphia.aggregation.stages

Class Unwind

java.lang.Object
dev.morphia.aggregation.stages.Stage
dev.morphia.aggregation.stages.Unwind
public class Unwind extends Stage
Deconstructs an array field from the input documents to output a document for each element. Each output document is the input document with the value of the array field replaced by the element.

  • Method Details

    • unwind

      public static Unwind unwind(String name)
      Creates a stage with the named array field
      Parameters:
      name - the array field
      Returns:
      this
      Since:
      2.2
      MongoDB documentation
      Aggregration Pipeline Stage: $unwind

    • includeArrayIndex

      public Unwind includeArrayIndex(String name)
      Optional. The name of a new field to hold the array index of the element. The name cannot start with a dollar sign $.
      Parameters:
      name - the new name
      Returns:
      this

    • preserveNullAndEmptyArrays

      public Unwind preserveNullAndEmptyArrays(Boolean preserveNullAndEmptyArrays)
      Optional.
      1. If true, if the path is null, missing, or an empty array, $unwind outputs the document.
      2. If false, if path is null, missing, or an empty array, $unwind does not output a document.
      Parameters:
      preserveNullAndEmptyArrays - true to preserve
      Returns:
      this