Package org.springframework.data.mongodb.core.aggregation

Enum Class SystemVariable

java.lang.Object

java.lang.Enum<SystemVariable>

org.springframework.data.mongodb.core.aggregation.SystemVariable

All Implemented Interfaces:

Serializable, Comparable<SystemVariable>, Constable

public enum SystemVariable
extends Enum<SystemVariable>

Describes the system variables available in MongoDB aggregation framework pipeline expressions.

Author:

Thomas Darimont, Christoph Strobl

See Also:

• Aggregation Variables.

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Enum

Enum.EnumDesc<E extends Enum<E>>

Enum Constant Summary

Enum Constants

Enum Constant	Description
CLUSTER_TIME	Variable for the current timestamp.
CURRENT	Variable that references the start of the field path being processed.
DESCEND	One of the allowed results of a $redact expression
KEEP	One of the allowed results of a $redact expression
NOW	Variable for the current datetime.
PRUNE	One of the allowed results of a $redact expression
REMOVE	Variable that evaluates to a missing value.
ROOT	Variable that references the root document.
SEARCH_META	A variable that stores the metadata results of an Atlas Search query.

Method Summary

Modifier and Type	Method	Description
static boolean	isReferingToSystemVariable(String fieldRef)	Return true if the given fieldRef denotes a well-known system variable, false otherwise.
String	toString()
static SystemVariable	valueOf(String name)	Returns the enum constant of this class with the specified name.
static SystemVariable[]	values()	Returns an array containing the constants of this enum class, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, describeConstable, equals, finalize, getDeclaringClass, hashCode, name, ordinal, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Details

NOW

public static final SystemVariable NOW

Variable for the current datetime.

Since:

4.0

CLUSTER_TIME

public static final SystemVariable CLUSTER_TIME

Variable for the current timestamp.

Since:

4.0

ROOT

public static final SystemVariable ROOT

Variable that references the root document.

CURRENT

public static final SystemVariable CURRENT

Variable that references the start of the field path being processed.

REMOVE

public static final SystemVariable REMOVE

Variable that evaluates to a missing value.

DESCEND

public static final SystemVariable DESCEND

One of the allowed results of a $redact expression

Since:

4.0

PRUNE

public static final SystemVariable PRUNE

One of the allowed results of a $redact expression

Since:

4.0

KEEP

public static final SystemVariable KEEP

One of the allowed results of a $redact expression

Since:

4.0

SEARCH_META

public static final SystemVariable SEARCH_META

A variable that stores the metadata results of an Atlas Search query.

Since:

4.0

Method Details

values

public static SystemVariable[] values()

Returns an array containing the constants of this enum class, in the order they are declared.

Returns:

an array containing the constants of this enum class, in the order they are declared

valueOf

public static SystemVariable valueOf(String name)

Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum class has no constant with the specified name

NullPointerException - if the argument is null

isReferingToSystemVariable

public static boolean isReferingToSystemVariable(@Nullable
 String fieldRef)

Return true if the given fieldRef denotes a well-known system variable, false otherwise.

Parameters:

fieldRef - may be null.

Returns:

true if the given field refers to a SystemVariable.

toString

public String toString()

Overrides:

toString in class Enum<SystemVariable>