org.apache.openjpa.persistence.criteria
Class PredicateImpl

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

All Implemented Interfaces:

Expression<Boolean>, Predicate, Selection<Boolean>, TupleElement<Boolean>, CriteriaExpression

Direct Known Subclasses:

CompareByExample, Expressions.BinaryLogicalExpression, Expressions.IsEmpty, Expressions.IsMember, Expressions.IsNotEmpty, Expressions.IsNotNull, Expressions.IsNull, Expressions.Like, Expressions.Not, Expressions.SubqueryPredicate, PredicateImpl.And, PredicateImpl.Or

abstract class PredicateImpl
extends ExpressionImpl<Boolean>
implements Predicate

Predicate is a expression that evaluates to true or false. All boolean expressions are implemented as Predicate. A predicate can have zero or more predicate arguments. Default predicate operator is AND (conjunction). Two constant predicates are Predicate.TRUE and Predicate.FALSE. AND predicate with no argument evaluates to TRUE. OR predicate with no argument evaluates to FALSE. Negation of a Predicate creates a new Predicate.

Since:

2.0.0

Author:

Pinaki Poddar, Fay Wang

Nested Class Summary

(package private) static class	PredicateImpl.And Concrete AND predicate.
(package private) static class	PredicateImpl.Or Concrete OR predicate.

Nested classes/interfaces inherited from interface javax.persistence.criteria.Predicate

Predicate.BooleanOperator

Field Summary

protected List<Predicate>	_exps
static Predicate	FALSE
static Predicate	TRUE

Constructor Summary

protected	PredicateImpl() An AND predicate with no arguments.
protected	PredicateImpl(Predicate.BooleanOperator op) A predicate with the given operator.
protected	PredicateImpl(Predicate.BooleanOperator op, Predicate... restrictions) A predicate of given operator with given arguments.

Method Summary

void	acceptVisit(CriteriaExpressionVisitor visitor) Accept visit from the given visitor.
PredicateImpl	add(Expression<Boolean> s) Adds the given predicate expression.
StringBuilder	asValue(AliasContext q) Get a string representation of this node as a value in the context of the given query.
List<Expression<Boolean>>	getExpressions()
Predicate.BooleanOperator	getOperator()
boolean	isEmpty()
boolean	isNegated() Is this predicate created by negating another predicate?
protected PredicateImpl	markNegated()
PredicateImpl	not() Returns a new predicate as the negation of this predicate.
(package private) Expression	toKernelExpression(ExpressionFactory factory, CriteriaQueryImpl<?> q) Bridge contract to convert this facade expression to a kernel expression.
(package private) 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.ExpressionImpl

as, in, in, in, in, isNotNull, isNull

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

alias, asProjection, assertValidName, 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.Expression

as, in, in, in, in, isNotNull, isNull

Methods inherited from interface javax.persistence.criteria.Selection

alias, getCompoundSelectionItems, isCompoundSelection

Methods inherited from interface javax.persistence.TupleElement

getAlias, getJavaType

Field Detail

TRUE

public static final Predicate TRUE

FALSE

public static final Predicate FALSE

_exps

protected final List<Predicate> _exps

Constructor Detail

PredicateImpl

protected PredicateImpl()

An AND predicate with no arguments.

PredicateImpl

protected PredicateImpl(Predicate.BooleanOperator op)

A predicate with the given operator.

PredicateImpl

protected PredicateImpl(Predicate.BooleanOperator op,
                        Predicate... restrictions)

A predicate of given operator with given arguments.

Method Detail

add

public PredicateImpl add(Expression<Boolean> s)

Adds the given predicate expression.

getExpressions

public List<Expression<Boolean>> getExpressions()

Specified by:

getExpressions in interface Predicate

getOperator

public final Predicate.BooleanOperator getOperator()

Specified by:

getOperator in interface Predicate

isEmpty

public final boolean isEmpty()

isNegated

public final boolean isNegated()

Is this predicate created by negating another predicate?

Specified by:

isNegated in interface Predicate

not

public PredicateImpl not()

Returns a new predicate as the negation of this predicate.
Note: Default negation creates a Not expression with this receiver as delegate. Derived predicates can return the inverse expression, if exists. For example, NotEqual for Equal or LessThan for GreaterThanEqual etc.

Specified by:

not in interface Predicate

markNegated

protected PredicateImpl markNegated()

toValue

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

Description copied from class: ExpressionImpl

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

Specified by:

toValue in class ExpressionImpl<Boolean>

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)

Description copied from class: ExpressionImpl

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

Overrides:

toKernelExpression in class ExpressionImpl<Boolean>

Parameters:

factory - creates the kernel expression

q - the query definition context of this expression

Returns:

an equivalent kernel expression

acceptVisit

public void acceptVisit(CriteriaExpressionVisitor visitor)

Description copied from interface: CriteriaExpression

Accept visit from the given visitor. The receiver is responsible to propagate the visitor to the constituent sub-nodes if any.

Specified by:

acceptVisit in interface CriteriaExpression

Overrides:

acceptVisit in class SelectionImpl<Boolean>

Parameters:

visitor - a processor to walk the nodes of a tree.

asValue

public StringBuilder asValue(AliasContext q)

Description copied from interface: CriteriaExpression

Get a string representation of this node as a value in the context of the given query.

Specified by:

asValue in interface CriteriaExpression

Overrides:

asValue in class SelectionImpl<Boolean>