/*
* Copyright 2015, The Querydsl Team (http://www.querydsl.com/team)
*
* Licensed 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, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.querydsl.jpa;
import com.querydsl.core.Tuple;
import com.querydsl.core.types.CollectionExpression;
import com.querydsl.core.types.EntityPath;
import com.querydsl.core.types.Expression;
import com.querydsl.core.types.Ops;
import com.querydsl.core.types.dsl.ComparableExpression;
import com.querydsl.core.types.dsl.Expressions;
import com.querydsl.core.types.dsl.StringExpression;
/**
* {@code JPAExpressions} provides factory methods for JPQL specific operations
* elements.
*
* @author tiwe
*/
@SuppressWarnings("unchecked")
public final class JPAExpressions {
/**
* Create a new detached JPQLQuery instance with the given projection
*
* @param expr projection
* @param <T>
* @return select(expr)
*/
public static <T> JPQLQuery<T> select(Expression<T> expr) {
return new JPASubQuery<Void>().select(expr);
}
/**
* Create a new detached JPQLQuery instance with the given projection
*
* @param exprs projection
* @return select(exprs)
*/
public static JPQLQuery<Tuple> select(Expression<?>... exprs) {
return new JPASubQuery<Void>().select(exprs);
}
/**
* Create a new detached JPQLQuery instance with the given projection
*
* @param expr projection
* @param <T>
* @return select(distinct expr)
*/
public static <T> JPQLQuery<T> selectDistinct(Expression<T> expr) {
return new JPASubQuery<Void>().select(expr).distinct();
}
/**
* Create a new detached JPQLQuery instance with the given projection
*
* @param exprs projection
* @return select(distinct expr)
*/
public static JPQLQuery<Tuple> selectDistinct(Expression<?>... exprs) {
return new JPASubQuery<Void>().select(exprs).distinct();
}
/**
* Create a new detached JPQLQuery instance with the projection zero
*
* @return select(0)
*/
public static JPQLQuery<Integer> selectZero() {
return select(Expressions.ZERO);
}
/**
* Create a new detached JPQLQuery instance with the projection one
*
* @return select(1)
*/
public static JPQLQuery<Integer> selectOne() {
return select(Expressions.ONE);
}
/**
* Create a new detached JPQLQuery instance with the given projection
*
* @param expr projection and source
* @param <T>
* @return select(expr).from(expr)
*/
public static <T> JPQLQuery<T> selectFrom(EntityPath<T> expr) {
return select(expr).from(expr);
}
/**
* Create a avg(col) expression
*
* @param col collection
* @return avg(col)
*/
public static <A extends Comparable<? super A>> ComparableExpression<A> avg(CollectionExpression<?,A> col) {
return Expressions.comparableOperation((Class) col.getParameter(0), Ops.QuantOps.AVG_IN_COL, (Expression<?>) col);
}
/**
* Create a max(col) expression
*
* @param left collection
* @return max(col)
*/
public static <A extends Comparable<? super A>> ComparableExpression<A> max(CollectionExpression<?,A> left) {
return Expressions.comparableOperation((Class) left.getParameter(0), Ops.QuantOps.MAX_IN_COL, (Expression<?>) left);
}
/**
* Create a min(col) expression
*
* @param left collection
* @return min(col)
*/
public static <A extends Comparable<? super A>> ComparableExpression<A> min(CollectionExpression<?,A> left) {
return Expressions.comparableOperation((Class) left.getParameter(0), Ops.QuantOps.MIN_IN_COL, (Expression<?>) left);
}
/**
* Create a type(path) expression
*
* @param path entity
* @return type(path)
*/
public static StringExpression type(EntityPath<?> path) {
return Expressions.stringOperation(JPQLOps.TYPE, path);
}
private JPAExpressions() { }
}