com.querydsl.jpa.JPAExpressions Maven / Gradle / Ivy
The newest version!
/*
* 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.ExpressionException;
import com.querydsl.core.types.Ops;
import com.querydsl.core.types.PathMetadata;
import com.querydsl.core.types.PathType;
import com.querydsl.core.types.dsl.BeanPath;
import com.querydsl.core.types.dsl.ComparableExpression;
import com.querydsl.core.types.dsl.Expressions;
import com.querydsl.core.types.dsl.StringExpression;
import javax.persistence.Entity;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.ParameterizedType;
/**
* {@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
* @return select(expr)
*/
public static JPQLQuery select(Expression expr) {
return new JPASubQuery().select(expr);
}
/**
* Create a new detached JPQLQuery instance with the given projection
*
* @param exprs projection
* @return select(exprs)
*/
public static JPQLQuery select(Expression... exprs) {
return new JPASubQuery().select(exprs);
}
/**
* Create a new detached JPQLQuery instance with the given projection
*
* @param expr projection
* @param
* @return select(distinct expr)
*/
public static JPQLQuery selectDistinct(Expression expr) {
return new JPASubQuery().select(expr).distinct();
}
/**
* Create a new detached JPQLQuery instance with the given projection
*
* @param exprs projection
* @return select(distinct expr)
*/
public static JPQLQuery selectDistinct(Expression... exprs) {
return new JPASubQuery().select(exprs).distinct();
}
/**
* Create a new detached JPQLQuery instance with the projection zero
*
* @return select(0)
*/
public static JPQLQuery selectZero() {
return select(Expressions.ZERO);
}
/**
* Create a new detached JPQLQuery instance with the projection one
*
* @return select(1)
*/
public static JPQLQuery selectOne() {
return select(Expressions.ONE);
}
/**
* Create a new detached JPQLQuery instance with the given projection
*
* @param expr projection and source
* @param
* @return select(expr).from(expr)
*/
public static JPQLQuery selectFrom(EntityPath expr) {
return select(expr).from(expr);
}
/**
* Create a JPA 2.1 treated path.
*
* @param path The path to apply the treat operation on
* @param subtype subtype class
* @param the subtype class
* @param the expression type
* @return subtype instance with the same identity
*/
public static , T> U treat(BeanPath path, Class subtype) {
try {
Class entitySubType = getConcreteEntitySubType(subtype);
PathMetadata pathMetadata = new PathMetadata(path, getEntityName(entitySubType), PathType.TREATED_PATH);
return subtype.getConstructor(PathMetadata.class).newInstance(pathMetadata);
} catch (InstantiationException e) {
throw new ExpressionException(e.getMessage(), e);
} catch (IllegalAccessException e) {
throw new ExpressionException(e.getMessage(), e);
} catch (InvocationTargetException e) {
throw new ExpressionException(e.getMessage(), e);
} catch (NoSuchMethodException e) {
throw new ExpressionException(e.getMessage(), e);
}
}
/**
* Create a avg(col) expression
*
* @param col collection
* @return avg(col)
*/
public static > ComparableExpression avg(CollectionExpression 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 > ComparableExpression max(CollectionExpression 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 > ComparableExpression min(CollectionExpression 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 static String getEntityName(Class clazz) {
final Entity entityAnnotation = clazz.getAnnotation(Entity.class);
if (entityAnnotation != null && entityAnnotation.name().length() > 0) {
return entityAnnotation.name();
} else if (clazz.getPackage() != null) {
String pn = clazz.getPackage().getName();
return clazz.getName().substring(pn.length() + 1);
} else {
return clazz.getName();
}
}
private static , T> Class getConcreteEntitySubType(Class subtype) {
return (Class) ((ParameterizedType) subtype.getGenericSuperclass()).getActualTypeArguments()[0];
}
private JPAExpressions() { }
}