Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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.apache.cayenne.tools.dbimport; import org.apache.cayenne.access.DbLoader; import org.apache.cayenne.configuration.ConfigurationTree; import org.apache.cayenne.configuration.DataNodeDescriptor; import org.apache.cayenne.configuration.server.DataSourceFactory; import org.apache.cayenne.configuration.server.DbAdapterFactory; import org.apache.cayenne.dba.DbAdapter; import org.apache.cayenne.di.Inject; import org.apache.cayenne.map.DataMap; import org.apache.cayenne.map.EntityResolver; import org.apache.cayenne.map.MapLoader; import org.apache.cayenne.map.ObjEntity; import org.apache.cayenne.map.ObjRelationship; import org.apache.cayenne.merge.AbstractToModelToken; import org.apache.cayenne.merge.AddRelationshipToDb; import org.apache.cayenne.merge.DbMerger; import org.apache.cayenne.merge.ExecutingMergerContext; import org.apache.cayenne.merge.MergerContext; import org.apache.cayenne.merge.MergerFactory; import org.apache.cayenne.merge.MergerToken; import org.apache.cayenne.merge.ModelMergeDelegate; import org.apache.cayenne.merge.ProxyModelMergeDelegate; import org.apache.cayenne.project.Project; import org.apache.cayenne.project.ProjectSaver; import org.apache.cayenne.resource.URLResource; import org.apache.cayenne.validation.SimpleValidationFailure; import org.apache.cayenne.validation.ValidationFailure; import org.apache.cayenne.validation.ValidationResult; import org.apache.commons.logging.Log; import org.xml.sax.InputSource; import javax.sql.DataSource; import java.io.File; import java.io.FileNotFoundException; import java.io.IOException; import java.sql.Connection; import java.util.Collection; import java.util.Collections; import java.util.Comparator; import java.util.LinkedList; import java.util.List; import static org.apache.commons.lang.StringUtils.isBlank; /** * A thin wrapper around {@link DbLoader} that encapsulates DB import logic for * the benefit of Ant and Maven db importers. * * @since 4.0 */ public class DbImportActionDefault implements DbImportAction { private final ProjectSaver projectSaver; private final Log logger; private final DataSourceFactory dataSourceFactory; private final DbAdapterFactory adapterFactory; private final MapLoader mapLoader; public DbImportActionDefault(@Inject Log logger, @Inject ProjectSaver projectSaver, @Inject DataSourceFactory dataSourceFactory, @Inject DbAdapterFactory adapterFactory, @Inject MapLoader mapLoader) { this.logger = logger; this.projectSaver = projectSaver; this.dataSourceFactory = dataSourceFactory; this.adapterFactory = adapterFactory; this.mapLoader = mapLoader; } public void execute(DbImportConfiguration config) throws Exception { if (logger.isDebugEnabled()) { logger.debug("DB connection: " + config.getDataSourceInfo()); } if (logger.isDebugEnabled()) { logger.debug(config); } DataNodeDescriptor dataNodeDescriptor = config.createDataNodeDescriptor(); DataSource dataSource = dataSourceFactory.getDataSource(dataNodeDescriptor); DbAdapter adapter = adapterFactory.createAdapter(dataNodeDescriptor, dataSource); DataMap loadedFomDb = load(config, adapter, dataSource.getConnection()); if (loadedFomDb == null) { logger.info("Nothing was loaded from db."); return; } DataMap existing = loadExistingDataMap(config.getDataMapFile()); if (existing == null) { logger.info(""); File file = config.getDataMapFile(); logger.info("Map file does not exist. Loaded db model will be saved into '" + (file == null ? "null" : file.getAbsolutePath() + "'")); saveLoaded(config.initializeDataMap(loadedFomDb)); } else { MergerFactory mergerFactory = adapter.mergerFactory(); List<MergerToken> mergeTokens = new DbMerger(mergerFactory).createMergeTokens(existing, loadedFomDb, config.getDbLoaderConfig()); if (mergeTokens.isEmpty()) { logger.info(""); logger.info("Detected changes: No changes to import."); return; } if (!isBlank(config.getDefaultPackage())) { existing.setDefaultPackage(config.getDefaultPackage()); } final Collection<ObjEntity> loadedObjEntities = new LinkedList<>(); DataMap executed = execute(new ProxyModelMergeDelegate(config.createMergeDelegate()) { @Override public void objEntityAdded(ObjEntity ent) { loadedObjEntities.add(ent); super.objEntityAdded(ent); } }, existing, log(sort(reverse(mergerFactory, mergeTokens)))); DbLoader.flattenManyToManyRelationships(executed, loadedObjEntities, config.getNameGenerator()); relationshipsSanity(executed); saveLoaded(executed); } } private void relationshipsSanity(DataMap executed) { for (ObjEntity objEntity : executed.getObjEntities()) { List<ObjRelationship> rels = new LinkedList<>(objEntity.getRelationships()); for (ObjRelationship rel : rels) { if (rel.getSourceEntity() == null || rel.getTargetEntity() == null) { logger.error("Incorrect obj relationship source or target entity is null: " + rel); objEntity.removeRelationship(rel.getName()); } } } } protected static List<MergerToken> sort(List<MergerToken> reverse) { Collections.sort(reverse, new Comparator<MergerToken>() { @Override public int compare(MergerToken o1, MergerToken o2) { if (o1 instanceof AddRelationshipToDb && o2 instanceof AddRelationshipToDb) { return 0; } if (!(o1 instanceof AddRelationshipToDb || o2 instanceof AddRelationshipToDb)) { return o1.getClass().getSimpleName().compareTo(o2.getClass().getSimpleName()); } return o1 instanceof AddRelationshipToDb ? 1 : -1; } }); return reverse; } private Collection<MergerToken> log(List<MergerToken> tokens) { logger.info(""); if (tokens.isEmpty()) { logger.info("Detected changes: No changes to import."); return tokens; } logger.info("Detected changes: "); for (MergerToken token : tokens) { logger.info(String.format(" %-20s %s", token.getTokenName(), token.getTokenValue())); } logger.info(""); return tokens; } protected DataMap loadExistingDataMap(File dataMapFile) throws IOException { if (dataMapFile != null && dataMapFile.exists() && dataMapFile.canRead()) { DataMap dataMap = mapLoader.loadDataMap(new InputSource(dataMapFile.getCanonicalPath())); dataMap.setNamespace(new EntityResolver(Collections.singleton(dataMap))); dataMap.setConfigurationSource(new URLResource(dataMapFile.toURI().toURL())); return dataMap; } return null; } private List<MergerToken> reverse(MergerFactory mergerFactory, Iterable<MergerToken> mergeTokens) throws IOException { List<MergerToken> tokens = new LinkedList<>(); for (MergerToken token : mergeTokens) { if (token instanceof AbstractToModelToken) { continue; } tokens.add(token.createReverse(mergerFactory)); } return tokens; } /** * Performs configured schema operations via DbGenerator. */ private DataMap execute(ModelMergeDelegate mergeDelegate, DataMap dataMap, Collection<MergerToken> tokens) { MergerContext mergerContext = new ExecutingMergerContext(dataMap, null, null, mergeDelegate); for (MergerToken tok : tokens) { try { tok.execute(mergerContext); } catch (Throwable th) { String message = "Migration Error. Can't apply changes from token: " + tok.getTokenName() + " (" + tok.getTokenValue() + ")"; logger.error(message, th); mergerContext.getValidationResult().addFailure(new SimpleValidationFailure(th, message)); } } ValidationResult failures = mergerContext.getValidationResult(); if (failures == null || !failures.hasFailures()) { logger.info("Migration Complete Successfully."); } else { logger.info("Migration Complete."); logger.warn("Migration finished. The following problem(s) were ignored."); for (ValidationFailure failure : failures.getFailures()) { logger.warn(failure.toString()); } } return dataMap; } private DbLoader getLoader(DbImportConfiguration config, DbAdapter adapter, Connection connection) throws InstantiationException, IllegalAccessException, ClassNotFoundException { return config.createLoader(adapter, connection, config.createLoaderDelegate()); } protected void saveLoaded(DataMap dataMap) throws FileNotFoundException { ConfigurationTree<DataMap> projectRoot = new ConfigurationTree<>(dataMap); Project project = new Project(projectRoot); projectSaver.save(project); } protected DataMap load(DbImportConfiguration config, DbAdapter adapter, Connection connection) throws Exception { DataMap dataMap = config.createDataMap(); try { DbLoader loader = config.createLoader(adapter, connection, config.createLoaderDelegate()); loader.load(dataMap, config.getDbLoaderConfig()); } finally { if (connection != null) { connection.close(); } } return dataMap; } }