Java tutorial
/* * Copyright 2015 the original author or authors members of codetrack.org * * 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.codetrack.database.file; import org.codetrack.annotation.definition.Feature; import org.codetrack.annotation.identify.Product; import org.codetrack.database.Database; import org.codetrack.database.DatabaseConnection; import org.codetrack.database.DatabaseParameters; import org.codetrack.database.DatabaseRepositoryFactory; import org.codetrack.domain.data.Project; import org.codetrack.repository.Repository; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.context.annotation.Scope; import org.springframework.stereotype.Component; import java.io.*; import java.util.Date; import java.util.Observable; import java.util.Observer; /** * File stream serializer DatabaseConnection implementation * * @author josecmoj at 02/05/15. * @see DatabaseConnection * @see FileDatabase * @see DatabaseParameters * @see FileDatabaseException */ @Product(id = "codetrack-file-database") @Feature(id = "#4-DATABASE") @Component @Scope("prototype") public class FileDatabaseConnection implements DatabaseConnection, Observer { public static String DATABASE_EXTENSION = ".dat"; public static String FILE_SEPARATOR = System.getProperty("file.separator"); /** * Database parameters information */ private DatabaseParameters databaseParameters; /** * Out file Stream used to save Database */ private OutputStream outFile; /** * Out buffer stream used to save Database */ private OutputStream outBuffer; /** * Object output used to save Database */ private ObjectOutput output; /** * In file stream to load Database */ private InputStream inFile; /** * In buffer stream used to load Database */ private InputStream inBuffer; /** * Object input to load Database */ private ObjectInput input; /** * Database file name */ private String fileName; /** * Codetrack base path name */ private String pathName; /** * Database graph instance */ private FileDatabase database; /** * Repository factory */ @Autowired private FileDatabaseRepositoryFactory repositoryFactory; public FileDatabaseConnection() { super(); } public FileDatabaseConnection(DatabaseParameters databaseParameters) { super(); this.databaseParameters = databaseParameters; } /** * {@inheritDoc} */ @Override public Database getDatabase() { return database; } /** * {@inheritDoc} */ @Override public void setDatabase(Database database) { this.database = (FileDatabase) database; } /** * {@inheritDoc} */ @Override public DatabaseParameters getDatabaseParameters() { return databaseParameters; } /** * {@inheritDoc} */ @Override public void setDatabaseParameters(DatabaseParameters databaseParameters) { this.databaseParameters = databaseParameters; } /** * Access file name * * @return String with file name */ public String getFileName() { return fileName; } /** * Setting file name * @param fileName - String with file name */ public void setFileName(String fileName) { this.fileName = fileName; } /** * Get path name * @return String with path name */ public String getPathName() { return pathName; } /** * Setting path name * @param pathName - String with path name */ public void setPathName(String pathName) { this.pathName = pathName; } /** * Close file output database (if is opened) * @throws Exception */ @Override public void close() throws Exception { if (output != null) { output.flush(); output.close(); output = null; } } /** * This simulate a open database connection operation * Set database file name to internal variable fileName * * @throws Exception */ @Override public void open() throws Exception { setPathName(databaseParameters.getPath() + FILE_SEPARATOR + "databases" + FILE_SEPARATOR + databaseParameters.getName()); setFileName(getPathName() + DATABASE_EXTENSION); } /** * Load database graph from database file * * @throws Exception * @throws FileDatabaseException */ @Override public void load() throws Exception { File file = new File(fileName); if (file.exists()) { inFile = new FileInputStream(file); inBuffer = new BufferedInputStream(inFile); input = new ObjectInputStream(inBuffer); this.database = (FileDatabase) input.readObject(); input.close(); } // File not exist and database is not create yet if (this.database == null) { this.database = FileDatabase.newBuilder().name(databaseParameters.getName()).lastUpdate(new Date()) .build(); } this.database.setConnection(this); this.database.addObserver(this); } /** * Save database graph in database file * * @throws Exception * @throws FileDatabaseException */ @Override public void save() throws Exception { if (database.isModified()) database.setLastUpdate(new Date()); File file = new File(fileName); try { if (!file.exists()) file.createNewFile(); if (file.exists()) { outFile = new FileOutputStream(file); outBuffer = new BufferedOutputStream(outFile); output = new ObjectOutputStream(outBuffer); output.writeObject(database); close(); } else throw new FileDatabaseException("Cannot save file " + file.getAbsolutePath()); } catch (Exception ex) { throw new FileDatabaseException("Cannot create file " + file.getCanonicalPath()); } } /** * Delete database file * * @throws Exception * @throws FileDatabaseException */ @Override public void delete() throws Exception { File file = new File(fileName); if (file.exists()) { try { file.delete(); } catch (Exception e) { throw new FileDatabaseException("Cannot delete file " + fileName); } } } /** * Access to database file state information * * @return String with status information */ @Override public String state() { StringBuilder builder = new StringBuilder(); builder.append("database: ").append(databaseParameters.getName()).append("|engine: ") .append(databaseParameters.getEngine().name()); File file = new File(fileName); if (file.exists()) { builder.append("|file: ").append(file.getAbsolutePath()).append("|size: ").append(file.length()); } return builder.toString(); } /** * Observer override update method, receive change notifications from FileDatabase * * @param o - Observable object instance (FileDatabase) * @param arg - changed data (optional) */ @Override public void update(Observable o, Object arg) { if (o instanceof FileDatabase) { try { switch (((FileDatabase) o).getState()) { case CHANGED: this.save(); } } catch (Exception e) { } } } /** * {@inheritDoc} */ @Override public DatabaseRepositoryFactory getRepositoryFactory() { return repositoryFactory; } /** * {@inheritDoc} */ @Override public <E> Repository<E> getRepository(Project project) { return repositoryFactory.getRepository(this.getDatabase(), project); } }