Java tutorial
/* * Copyright 2014 Tagbangers, Inc. * * 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 org.wallride.repository; import org.springframework.data.jpa.domain.Specification; import org.wallride.domain.Article; import org.wallride.domain.Article_; import javax.persistence.criteria.Predicate; import javax.persistence.criteria.Root; import javax.persistence.criteria.Subquery; import java.util.ArrayList; import java.util.List; public class ArticleSpecifications { public static Specification<Article> draft(Article article) { return (root, query, cb) -> { List<Predicate> predicates = new ArrayList<>(); predicates.add(cb.equal(root.get(Article_.drafted), article)); Subquery<Long> subquery = query.subquery(Long.class); Root<Article> p = subquery.from(Article.class); subquery.select(cb.max(p.get(Article_.id))).where(cb.equal(p.get(Article_.drafted), article)); predicates.add(cb.equal(root.get(Article_.id), subquery)); return cb.and(predicates.toArray(new Predicate[0])); }; } }