org.datanucleus.api.jdo.query

Class ExpressionImpl<T>

java.lang.Object

org.datanucleus.api.jdo.query.ExpressionImpl<T>

All Implemented Interfaces:

Expression<T>

Direct Known Subclasses:

CollectionExpressionImpl, ComparableExpressionImpl, MapExpressionImpl, ObjectExpressionImpl, PersistableExpressionImpl

public class ExpressionImpl<T>
extends Object
implements Expression<T>

Implementation of the methods for Expression, to be extended by the XXXExpressionImpl classes.

Constructor Summary

Constructors

Constructor and Description
ExpressionImpl(Class<T> cls, String name, ExpressionType type) Constructor for a parameter or variable of this type.
ExpressionImpl(org.datanucleus.query.expression.Expression queryExpr) Constructor taking in the query expression being represented.
ExpressionImpl(PersistableExpression parent, String name) Constructor, extending a parent, and accessing a member of that parent.

Method Summary

Modifier and Type	Method and Description
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.
org.datanucleus.query.expression.Expression	getQueryExpression() Accessor for the underlying (generic) query expression.
BooleanExpression	instanceOf(Class cls) Return an expression for whether this expression is an instanceof the supplied class.
boolean	isParameter()
boolean	isVariable()
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.

Methods inherited from class java.lang.Object

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

Constructor Detail

ExpressionImpl

public ExpressionImpl(PersistableExpression parent,
                      String name)

Constructor, extending a parent, and accessing a member of that parent.

Parameters:

parent - The parent expression (or null, if candidate)

name - Name of the member to access

ExpressionImpl

public ExpressionImpl(Class<T> cls,
                      String name,
                      ExpressionType type)

Constructor for a parameter or variable of this type.

Parameters:

cls - The type of the parameter/variable

name - Name of the member to access

type - The type, whether parameter or variable

ExpressionImpl

public ExpressionImpl(org.datanucleus.query.expression.Expression queryExpr)

Constructor taking in the query expression being represented.

Parameters:

queryExpr - The (generic) query expression

Method Detail

getQueryExpression

public org.datanucleus.query.expression.Expression getQueryExpression()

Accessor for the underlying (generic) query expression.

Returns:

The query expression

isParameter

public boolean isParameter()

isVariable

public boolean isVariable()

eq

public BooleanExpression eq(Expression expr)

Description copied from interface: Expression

Method returning whether this expression equals the other expression.

Specified by:

eq in interface Expression<T>

Parameters:

expr - Other expression

Returns:

Whether they are equal

eq

public BooleanExpression eq(T t)

Description copied from interface: Expression

Method returning whether this expression equals the literal.

Specified by:

eq in interface Expression<T>

Parameters:

t - Literal

Returns:

Whether they are equal

ne

public BooleanExpression ne(Expression expr)

Description copied from interface: Expression

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

Specified by:

ne in interface Expression<T>

Parameters:

expr - Other expression

Returns:

Whether they are not equal

ne

public BooleanExpression ne(T t)

Description copied from interface: Expression

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

Specified by:

ne in interface Expression<T>

Parameters:

t - literal

Returns:

Whether they are not equal

instanceOf

public BooleanExpression instanceOf(Class cls)

Description copied from interface: Expression

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

Specified by:

instanceOf in interface Expression<T>

Parameters:

cls - Class to check against

Returns:

Whether it is an instanceof

cast

public Expression cast(Class cls)

Description copied from interface: Expression

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

Specified by:

cast in interface Expression<T>

Parameters:

cls - Class to cast to

Returns:

The cast expression

count

public NumericExpression<Long> count()

Description copied from interface: Expression

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

Specified by:

count in interface Expression<T>

Returns:

Numeric expression for the count

countDistinct

public NumericExpression<Long> countDistinct()

Description copied from interface: Expression

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

Specified by:

countDistinct in interface Expression<T>

Returns:

Numeric expression for the distinct count