org.apache.openjpa.persistence.criteria
Class ExpressionImpl<X>

java.lang.Object
  org.apache.openjpa.persistence.criteria.SelectionImpl<X>
      org.apache.openjpa.persistence.criteria.ExpressionImpl<X>

Type Parameters:

X - the type of the value this expression represents.

All Implemented Interfaces:

Expression<X>, Selection<X>, TupleElement<X>, CriteriaExpression

Direct Known Subclasses:

Expressions.BinarayFunctionalExpression, Expressions.Case, Expressions.CastAs, Expressions.Coalesce, Expressions.Constant, Expressions.CurrentDate, Expressions.CurrentTime, Expressions.CurrentTimestamp, Expressions.FunctionalExpression, Expressions.ListArgument, Expressions.Locate, Expressions.Nullif, Expressions.SimpleCase, Expressions.SubqueryExpression, Expressions.UnaryFunctionalExpression, Joins.MapEntry, ParameterExpressionImpl, PathImpl, PredicateImpl, SubqueryImpl

abstract class ExpressionImpl<X>
extends SelectionImpl<X>
implements Expression<X>

Expression node for Criteria query. Acts a bridge pattern to equivalent kernel representation.

Since:

2.0.0

Author:

Pinaki Poddar

Constructor Summary

ExpressionImpl(Class<X> cls)

Method Summary

<Y> Expression<Y>	as(Class<Y> type) Creates a new expression of the given type.
Predicate	in(Collection<?> values) Create a predicate to test whether this expression is a member of the given collection element values.
Predicate	in(Expression<?>... values) Create a predicate to test whether this expression is a member of the given argument expressions.
Predicate	in(Expression<Collection<?>> values) Create a predicate to test whether this expression is a member of the given expression representing a collection.
Predicate	in(Object... values) Create a predicate to test whether this expression is a member of the given argument values.
Predicate	isNotNull() Create a predicate to test whether this expression is not null.
Predicate	isNull() Create a predicate to test whether this expression is null.
(package private) Expression	toKernelExpression(ExpressionFactory factory, CriteriaQueryImpl<?> q) Bridge contract to convert this facade expression to a kernel expression.
(package private) abstract Value	toValue(ExpressionFactory factory, CriteriaQueryImpl<?> q) Bridge contract to convert this facade expression to a kernel value.

Methods inherited from class org.apache.openjpa.persistence.criteria.SelectionImpl

acceptVisit, alias, asProjection, assertValidName, asValue, asVariable, getAlias, getCompoundSelectionItems, getJavaType, isAliased, isAutoAliased, isCompoundSelection, setAutoAlias

Methods inherited from class java.lang.Object

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

Methods inherited from interface javax.persistence.criteria.Selection

alias, getCompoundSelectionItems, isCompoundSelection

Methods inherited from interface javax.persistence.TupleElement

getAlias, getJavaType

Constructor Detail

ExpressionImpl

public ExpressionImpl(Class<X> cls)

Parameters:

cls - the type of the evaluated result of the expression

Method Detail

as

public <Y> Expression<Y> as(Class<Y> type)

Creates a new expression of the given type. If the given type is same as this expression's type then returns the same instance. May cause runtime cast failure if this expression's immutable type is not convertible to the given type.

Specified by:

as in interface Expression<X>

in

public Predicate in(Object... values)

Create a predicate to test whether this expression is a member of the given argument values.

Specified by:

in in interface Expression<X>

in

public Predicate in(Expression<?>... values)

Create a predicate to test whether this expression is a member of the given argument expressions.

Specified by:

in in interface Expression<X>

in

public Predicate in(Collection<?> values)

Create a predicate to test whether this expression is a member of the given collection element values.

Specified by:

in in interface Expression<X>

in

public Predicate in(Expression<Collection<?>> values)

Create a predicate to test whether this expression is a member of the given expression representing a collection.

Specified by:

in in interface Expression<X>

isNotNull

public Predicate isNotNull()

Create a predicate to test whether this expression is not null.

Specified by:

isNotNull in interface Expression<X>

isNull

public Predicate isNull()

Create a predicate to test whether this expression is null.

Specified by:

isNull in interface Expression<X>

toValue

abstract Value toValue(ExpressionFactory factory,
                       CriteriaQueryImpl<?> q)

Bridge contract to convert this facade expression to a kernel value.

Parameters:

factory - creates the kernel expression

q - the query definition context of this expression

Returns:

an equivalent kernel value

toKernelExpression

Expression toKernelExpression(ExpressionFactory factory,
                              CriteriaQueryImpl<?> q)

Bridge contract to convert this facade expression to a kernel expression.

Parameters:

factory - creates the kernel expression

q - the query definition context of this expression

Returns:

an equivalent kernel expression