Java tutorial
/* * 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.ngrinder.agent.repository; import javax.persistence.criteria.CriteriaBuilder; import javax.persistence.criteria.CriteriaQuery; import javax.persistence.criteria.Expression; import javax.persistence.criteria.Predicate; import javax.persistence.criteria.Root; import net.grinder.message.console.AgentControllerState; import org.ngrinder.model.AgentInfo; import org.springframework.data.jpa.domain.Specification; /** * Agent Manager JPA Specification. * * @author Mavlarn * @author JunHo Yoon * @since 3.1 */ public abstract class AgentManagerSpecification { /** * Query specification to query the agent existing in the specified region. * * @param region region to query * @return Specification of this query */ public static Specification<AgentInfo> startWithRegion(final String region) { return new Specification<AgentInfo>() { @Override public Predicate toPredicate(Root<AgentInfo> root, CriteriaQuery<?> query, CriteriaBuilder cb) { Expression<String> regionField = root.get("region").as(String.class); return cb.or(cb.like(regionField, region + "/_owned%", cb.literal('/')), cb.equal(regionField, region)); } }; } /** * Query specification to query the active agents. * * @return Specification of this query */ public static Specification<AgentInfo> active() { return new Specification<AgentInfo>() { @Override public Predicate toPredicate(Root<AgentInfo> root, CriteriaQuery<?> query, CriteriaBuilder cb) { Expression<AgentControllerState> status = root.get("state").as(AgentControllerState.class); return cb.and(cb.notEqual(status, AgentControllerState.INACTIVE), cb.notEqual(status, AgentControllerState.UNKNOWN), cb.notEqual(status, AgentControllerState.WRONG_REGION)); } }; } /** * Query specification to query the visible agents. "visible" means.. it's * visible by the agent monitor. * * @return Specification of this query */ public static Specification<AgentInfo> visible() { return new Specification<AgentInfo>() { @Override public Predicate toPredicate(Root<AgentInfo> root, CriteriaQuery<?> query, CriteriaBuilder cb) { Expression<AgentControllerState> status = root.get("state").as(AgentControllerState.class); return cb.notEqual(status, AgentControllerState.INACTIVE); } }; } }