Package com.datastax.astra.client.model

Class Projections

java.lang.Object

com.datastax.astra.client.model.Projections

public class Projections
extends Object

Encode the presence of a field in the result.

Method Summary

Modifier and Type	Method	Description
static Projection[]	exclude(String... field)	Exclude a field in the result.
static Projection[]	include(String... field)	Include a field in the result.
static Projection	slice(String field, Integer start, Integer end)	Specifies the number of elements in an array to return in the query result.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

include

public static Projection[] include(String... field)

Include a field in the result.

Parameters:

field - include field

Returns:

name to include

slice

public static Projection slice(String field,
 Integer start,
 Integer end)

Specifies the number of elements in an array to return in the query result.

 
 // Return the first two elements
 { $slice: 2 }

 // Return the last two elements
 { $slice: -2 }

 // Skip 4 elements (from 0th index), return the next 2
 { $slice: [4, 2] }

 // Skip backward 4 elements, return next 2 elements (forward)
 { $slice: [-4, 2] }
 
 

Parameters:

field - field name for slice

start - start index of slice

end - end index of slice

Returns:

a projection for the slide

exclude

public static Projection[] exclude(String... field)

Exclude a field in the result.

Parameters:

field - field name to exclude

Returns:

list of projection