Java tutorial
/* * Copyright (c) 2008-2016 Haulmont. * * 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.haulmont.restapi.config; import com.google.common.base.Strings; import com.haulmont.bali.util.Dom4j; import com.haulmont.cuba.core.global.Resources; import com.haulmont.cuba.core.global.View; import com.haulmont.cuba.core.sys.AppContext; import org.apache.commons.io.IOUtils; import org.apache.commons.lang.text.StrTokenizer; import org.dom4j.Element; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.core.io.Resource; import org.springframework.stereotype.Component; import javax.annotation.Nullable; import javax.inject.Inject; import java.io.IOException; import java.io.InputStream; import java.util.ArrayList; import java.util.List; import java.util.concurrent.locks.ReadWriteLock; import java.util.concurrent.locks.ReentrantReadWriteLock; import java.util.stream.Collectors; /** * Class is used for loading and storing of predefined JPQL queries that are used by the REST API. Queries are loaded * from configuration files defined by the {@code cuba.rest.queriesConfig} application property. * <p> * Queries with the name defined by the {@link #ALL_ENTITIES_QUERY_NAME} field should not be present in the queries * config. If the query with this name is requested, the {@link QueryInfo} for the query that returns all entities will * be returned. */ @Component("cuba_RestQueriesConfiguration") public class RestQueriesConfiguration { protected final String CUBA_REST_QUERIES_CONFIG_PROP_NAME = "cuba.rest.queriesConfig"; private final Logger log = LoggerFactory.getLogger(RestQueriesConfiguration.class); protected volatile boolean initialized; protected ReadWriteLock lock = new ReentrantReadWriteLock(); @Inject protected Resources resources; protected List<QueryInfo> queries = new ArrayList<>(); public static final String ALL_ENTITIES_QUERY_NAME = "all"; /** * Returns a query description with the given name for the given entity. * * @param entityName entity name * @param queryName query name * @return query description */ @Nullable public QueryInfo getQuery(String entityName, String queryName) { lock.readLock().lock(); try { checkInitialized(); if (ALL_ENTITIES_QUERY_NAME.equalsIgnoreCase(queryName)) { return createAllEntitiesQuery(entityName); } for (QueryInfo query : queries) { if (queryName.equals(query.getName()) && entityName.equals(query.getEntityName())) { return query; } } return null; } finally { lock.readLock().unlock(); } } public List<QueryInfo> getQueries() { lock.readLock().lock(); try { checkInitialized(); return queries; } finally { lock.readLock().unlock(); } } public List<QueryInfo> getQueries(String entityName) { lock.readLock().lock(); try { checkInitialized(); return queries.stream().filter(queryInfo -> entityName.equals(queryInfo.getEntityName())) .collect(Collectors.toList()); } finally { lock.readLock().unlock(); } } protected void checkInitialized() { if (!initialized) { lock.readLock().unlock(); lock.writeLock().lock(); try { if (!initialized) { init(); initialized = true; } } finally { lock.readLock().lock(); lock.writeLock().unlock(); } } } protected void init() { String configName = AppContext.getProperty(CUBA_REST_QUERIES_CONFIG_PROP_NAME); StrTokenizer tokenizer = new StrTokenizer(configName); for (String location : tokenizer.getTokenArray()) { Resource resource = resources.getResource(location); if (resource.exists()) { InputStream stream = null; try { stream = resource.getInputStream(); loadConfig(Dom4j.readDocument(stream).getRootElement()); } catch (IOException e) { throw new RuntimeException(e); } finally { IOUtils.closeQuietly(stream); } } else { log.warn("Resource " + location + " not found, ignore it"); } } } protected void loadConfig(Element rootElem) { for (Element queryElem : Dom4j.elements(rootElem, "query")) { String queryName = queryElem.attributeValue("name"); if (ALL_ENTITIES_QUERY_NAME.equalsIgnoreCase(queryName)) { log.error("{} is a predefined query name. It can not be used.", queryName); continue; } String entityName = queryElem.attributeValue("entity"); String viewName = queryElem.attributeValue("view"); String jpql = queryElem.elementText("jpql"); if (Strings.isNullOrEmpty(queryName)) { log.error("queryName attribute is not defined"); continue; } if (Strings.isNullOrEmpty(entityName)) { log.error("entityName attribute is not defined"); continue; } if (Strings.isNullOrEmpty(viewName)) { log.error("viewName attribute is not defined"); continue; } if (Strings.isNullOrEmpty(jpql)) { log.error("Query jpql is not defined"); continue; } QueryInfo queryInfo = new QueryInfo(); queryInfo.setName(queryName); queryInfo.setEntityName(entityName); queryInfo.setViewName(viewName); queryInfo.setJpql(jpql); Element paramsEl = queryElem.element("params"); if (paramsEl != null) { for (Element paramElem : Dom4j.elements(paramsEl, "param")) { String paramName = paramElem.attributeValue("name"); String paramType = paramElem.attributeValue("type"); QueryParamInfo param = new QueryParamInfo(paramName, paramType); queryInfo.getParams().add(param); } } queries.add(queryInfo); } } protected QueryInfo createAllEntitiesQuery(String entityName) { QueryInfo queryInfo = new QueryInfo(); queryInfo.setName(ALL_ENTITIES_QUERY_NAME); queryInfo.setEntityName(entityName); queryInfo.setViewName(View.MINIMAL); queryInfo.setJpql(String.format("select e from %s e", entityName)); return queryInfo; } /** * Class stores an information about the predefined JPQL query */ public static class QueryInfo { protected String name; protected String jpql; protected String entityName; protected String viewName; protected List<QueryParamInfo> params = new ArrayList<>(); public String getName() { return name; } public void setName(String name) { this.name = name; } public String getJpql() { return jpql; } public void setJpql(String jpql) { this.jpql = jpql; } public String getEntityName() { return entityName; } public void setEntityName(String entityName) { this.entityName = entityName; } public String getViewName() { return viewName; } public void setViewName(String viewName) { this.viewName = viewName; } public List<QueryParamInfo> getParams() { return params; } public void setParams(List<QueryParamInfo> params) { this.params = params; } } /** * Class stores an information about the predefined JPQL query parameter */ public static class QueryParamInfo { protected String name; protected String type; public QueryParamInfo(String name, String type) { this.name = name; this.type = type; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getType() { return type; } public void setType(String type) { this.type = type; } } }