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the base moudle of ibankapp series

There is a newer version: 1.0.0-beta.6

/*
 * iBankApp
 *
 * License : Apache License,Version 2.0, January 2004
 *
 * See the LICENSE file in English or LICENSE.zh_CN in chinese
 * in the root directory or .
 */

package org.ibankapp.base.persistence.Specification;

import org.ibankapp.base.persistence.domain.Specification;

import javax.persistence.EntityManager;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.ParameterExpression;
import javax.persistence.criteria.Path;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;
import javax.persistence.metamodel.IdentifiableType;
import javax.persistence.metamodel.ManagedType;

/**
 * 通过ID集合进行实体查询的Specification
 *
 * @param  实体类型
 * @author ibankapp
 * @author codelder
 * @since 1.0.0
 */
public class ByIdsSpecification implements Specification {

    public ParameterExpression parameter;
    private EntityManager em;
    private Class entityClass;

    public ByIdsSpecification(EntityManager em, Class entityClass) {
        this.em = em;
        this.entityClass = entityClass;
    }

    /**
     * 获取按ID集合进行实体查询的Predicate
     *
     * @param root  实体类ROOT
     * @param query 条件查询
     * @param cb    查询构建器
     */
    @Override
    @SuppressWarnings("unchecked")
    public Predicate toPredicate(Root root, CriteriaQuery query, CriteriaBuilder cb) {

        ManagedType type = em.getMetamodel().managedType(entityClass);

        IdentifiableType identifiableType = (IdentifiableType) type;

        Path path = root.get(identifiableType.getId(identifiableType.getIdType().getJavaType()));

        parameter = cb.parameter(Iterable.class);
        return path.in(parameter);
    }
}