Package dev.morphia.aggregation.expressions

Class Expressions

java.lang.Object

dev.morphia.aggregation.expressions.Expressions

public final class Expressions
extends Object

Defines helper methods for various expressions.

Since:

2.0

Method Summary

Modifier and Type	Method	Description
static DocumentExpression	document()	Creates a new DocumentExpression.
static DocumentExpression	document(String name, Expression expression)	Creates a new DocumentExpression.
static Expression	field(String name)	Creates a field expression for the given value.
static Expression	literal(Object value)	Returns a value without parsing.
static Expression	meta()	Returns the metadata associated with a document in a pipeline operations, e.g.
static DocumentExpression	of()	Deprecated, for removal: This API element is subject to removal in a future version. use document() or document(String, Expression)
static <T> List<T>	toList(T first, T... additional)
static ValueExpression	value(Object value)	Returns a value without parsing.

Methods inherited from class java.lang.Object

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

Method Detail

document

public static DocumentExpression document()

Creates a new DocumentExpression.

Returns:

the new expression

Since:

2.3

document

public static DocumentExpression document(String name,
                                          Expression expression)

Creates a new DocumentExpression.

Parameters:

name - the first field name

expression - the first field value

Returns:

the new expression

Since:

2.3

field

public static Expression field(String name)

Creates a field expression for the given value. If the value does not already start with '$', it will be prepended automatically.

Parameters:

name - the field name

Returns:

the new expression

literal

public static Expression literal(Object value)

Returns a value without parsing. Use for values that the aggregation pipeline may interpret as an expression.

Parameters:

value - the value

Returns:

the new expression

MongoDB documentation

Aggregration Expression: $literal

meta

public static Expression meta()

Returns the metadata associated with a document in a pipeline operations, e.g. "textScore" when performing text search.

Returns:

the new expression

MongoDB documentation

Aggregration Expression: $meta

of

@Deprecated(forRemoval=true,
            since="2.3")
public static DocumentExpression of()

Deprecated, for removal: This API element is subject to removal in a future version.

use document() or document(String, Expression)

Creates a new DocumentExpression.

Returns:

the new expression

toList

@MorphiaInternal
public static <T> List<T> toList(T first,
                                 T... additional)

Type Parameters:

T - the element type

Parameters:

first - the first item

additional - additional items

Returns:

a list of them all

Developer note.

This is an internal item. Its function and presence are subject to change without warning. Its use is highly discouraged.

value

public static ValueExpression value(@Nullable
                                    Object value)

Returns a value without parsing. Note that this is different from literal(Object) in that the given value will dropped directly in to the pipeline for use/evaluation in whatever context the value is used.

Parameters:

value - the value

Returns:

the new expression