org.apache.openjpa.persistence.criteria.ExpressionImpl Maven / Gradle / Ivy
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* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
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* specific language governing permissions and limitations
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*/
package org.apache.openjpa.persistence.criteria;
import java.util.Collection;
import javax.persistence.criteria.CriteriaBuilder.In;
import javax.persistence.criteria.Expression;
import javax.persistence.criteria.Predicate;
import org.apache.openjpa.kernel.exps.ExpressionFactory;
/**
* Expression node for Criteria query.
* Acts a bridge pattern to equivalent kernel representation.
*
* @param the type of the value this expression represents.
*
* @author Pinaki Poddar
* @since 2.0.0
*/
abstract class ExpressionImpl extends SelectionImpl implements Expression {
/**
* @param cls the type of the evaluated result of the expression
*/
public ExpressionImpl(Class cls) {
super(cls);
}
/**
* 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.
*/
@Override
public Expression as(Class type) {
return type == getJavaType() ? (Expression)this : new Expressions.CastAs<>(type, this);
}
/**
* Create a predicate to test whether this expression is a member of the given argument values.
*/
@Override
public Predicate in(Object... values) {
In result = new Expressions.In<>(this);
for (Object v : values)
result.value((X)v);
return result;
}
/**
* Create a predicate to test whether this expression is a member of the given argument expressions.
*/
@Override
public Predicate in(Expression... values) {
In result = new Expressions.In<>(this);
for (Expression e : values)
result.value((Expression)e);
return result;
}
/**
* Create a predicate to test whether this expression is a member of the given collection element values.
*/
@Override
public Predicate in(Collection values) {
In result = new Expressions.In<>(this);
for (Object e : values)
result.value((X)e);
return result;
}
/**
* Create a predicate to test whether this expression is a member of the given expression representing a collection.
*/
@Override
public Predicate in(Expression> values) {
In result = new Expressions.In<>(this);
result.value((Expression)values);
return result;
}
/**
* Create a predicate to test whether this expression is not null.
*/
@Override
public Predicate isNotNull() {
return new Expressions.IsNotNull(this);
}
/**
* Create a predicate to test whether this expression is null.
*/
@Override
public Predicate isNull() {
return new Expressions.IsNull(this);
}
// ------------------------------------------------------------------------------------
// Contract for bridge pattern to convert to an equivalent kernel representation.
// ------------------------------------------------------------------------------------
/**
* Bridge contract to convert this facade expression to a kernel value.
* @param factory creates the kernel expression
* @param q the query definition context of this expression
* @return an equivalent kernel value
*/
abstract org.apache.openjpa.kernel.exps.Value toValue(ExpressionFactory factory, CriteriaQueryImpl q);
/**
* Bridge contract to convert this facade expression to a kernel expression.
* @param factory creates the kernel expression
* @param q the query definition context of this expression
* @return an equivalent kernel expression
*/
org.apache.openjpa.kernel.exps.Expression toKernelExpression(ExpressionFactory factory, CriteriaQueryImpl q) {
return factory.asExpression(toValue(factory, q));
}
}