javax.jdo.query

Interface Expression<T>

Type Parameters:

T - Java type being represented here

All Known Subinterfaces:

BooleanExpression, ByteExpression, CharacterExpression, CollectionExpression<T,E>, ComparableExpression<T>, DateExpression, DateTimeExpression, EnumExpression<T>, IfThenElseExpression<T>, ListExpression<T,E>, LocalDateExpression, LocalDateTimeExpression, LocalTimeExpression, MapExpression<T,K,V>, NumericExpression<T>, ObjectExpression<T>, OptionalExpression<T>, PersistableExpression<T>, StringExpression, TimeExpression

public interface Expression<T>

Representation of an expression in a query.

Method Summary

Modifier and Type	Method and Description
Expression	as(String alias) Method to return an expression with the specified alias assigned to this expression.
Expression	cast(Class cls) Return an expression where this expression is cast to the specified type.
NumericExpression<Long>	count() Method to return a numeric expression representing the aggregated count of this expression.
NumericExpression<Long>	countDistinct() Method to return a numeric expression representing the aggregated (distinct) count of this expression.
BooleanExpression	eq(Expression expr) Method returning whether this expression equals the other expression.
BooleanExpression	eq(T t) Method returning whether this expression equals the literal.
BooleanExpression	instanceOf(Class cls) Return an expression for whether this expression is an instanceof the supplied class.
BooleanExpression	ne(Expression expr) Method returning whether this expression doesn't equal the other expression.
BooleanExpression	ne(T t) Method returning whether this expression doesn't equal the literal.

Method Detail

eq

BooleanExpression eq(Expression expr)

Method returning whether this expression equals the other expression.

Parameters:

expr - Other expression

Returns:

Whether they are equal

eq

BooleanExpression eq(T t)

Method returning whether this expression equals the literal.

Parameters:

t - Literal

Returns:

Whether they are equal

ne

BooleanExpression ne(Expression expr)

Method returning whether this expression doesn't equal the other expression.

Parameters:

expr - Other expression

Returns:

Whether they are not equal

ne

BooleanExpression ne(T t)

Method returning whether this expression doesn't equal the literal.

Parameters:

t - literal

Returns:

Whether they are not equal

count

NumericExpression<Long> count()

Method to return a numeric expression representing the aggregated count of this expression.

Returns:

Numeric expression for the count

countDistinct

NumericExpression<Long> countDistinct()

Method to return a numeric expression representing the aggregated (distinct) count of this expression.

Returns:

Numeric expression for the distinct count

instanceOf

BooleanExpression instanceOf(Class cls)

Return an expression for whether this expression is an instanceof the supplied class.

Parameters:

cls - Class to check against

Returns:

Whether it is an instanceof

cast

Expression cast(Class cls)

Return an expression where this expression is cast to the specified type.

Parameters:

cls - Class to cast to

Returns:

The cast expression

as

Expression as(String alias)

Method to return an expression with the specified alias assigned to this expression.

Parameters:

alias - the alias for this expression

Returns:

the expression with an alias