Java tutorial
package ch.ge.ve.commons.fileutils; /*- * #%L * Common file utilities * %% * Copyright (C) 2015 - 2016 Rpublique et Canton de Genve * %% * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. * #L% */ import org.joda.time.DateTime; import java.io.IOException; import java.nio.file.Files; import java.nio.file.Path; import java.text.SimpleDateFormat; import java.util.Optional; import java.util.regex.Pattern; import java.util.stream.Stream; /** * Utility class to manage the parametrized output file names. * <p/> * The supported parameters are the following and are replaced at runtime with the given values: * <ul> * <li>{date}: the date of the file generation in 'yyyyMMdd' format</li> * <li>{datetime}: date and time of the file generation in 'yyyy-MM-dd-HH'h'mm'm'ss's'' format</li> * <li>{user}: the user of the application: the windows account name</li> * <li>{operationCode}: the code of the operation for which the file is generated</li> * <li>{canton}: the canton of the operation for which the file is generated</li> * </ul> */ public class OutputFilesPattern { public static final String DATE_TIME_FORMAT = "yyyy-MM-dd-HH'h'mm'm'ss's'"; public static final String DATE_FORMAT = "yyyyMMdd"; private static final int FIND_FILES_MAX_DEPTH = 10; private final SimpleDateFormat datetimeFormat = new SimpleDateFormat(DATE_TIME_FORMAT); private final SimpleDateFormat dateFormat = new SimpleDateFormat(DATE_FORMAT); /** * Resolves the parameters {date}, {datetime} and {user} * * @param pattern * @param user * @param date * @return */ public String injectParams(String pattern, String user, DateTime date) { String result = pattern.replace("{date}", getDateAsString(date)); result = result.replace("{datetime}", getDateTimeAsString(date)); result = result.replace("{user}", user); return result; } /** * Resolves the parameters {date}, {datetime} and {user}.</br> * user is resolved from environment variable 'user.name' * * @param pattern parametrized file name * @param date the date and time of the file generation * @return the final file name */ public String injectParams(String pattern, DateTime date) { return injectParams(pattern, getSystemUserName(), date); } /** * Resolves the parameters {date}, {datetime}, {user} and {operationCode} * * @param pattern parametrized file name * @param user user * @param date the date and time of the file generation * @param operationCode the code of the operation * @return the final file name */ public String injectParams(String pattern, String user, DateTime date, String operationCode) { String result = injectParams(pattern, user, date); result = result.replace("{operationCode}", operationCode); return result; } /** * Resolves the parameters {date}, {datetime}, {user} and {operationCode} * * @param pattern parametrized file name * @param date the date and time of the file generation * @param operationCode the code of the operation * @return the final file name */ public String injectParams(String pattern, DateTime date, String operationCode) { return injectParams(pattern, getSystemUserName(), date, operationCode); } /** * Resolves all the parameters. * * @param pattern parametrized file name * @param user user * @param date the date and time of the file generation * @param operationCode the code of the operation * @param hostingCode the canton of the operation * @return the final file name */ public String injectParams(String pattern, String user, DateTime date, String operationCode, String hostingCode) { String result = injectParams(pattern, user, date, operationCode); result = result.replace("{canton}", hostingCode); return result; } /** * Resolves all the parameters. * * @param pattern parametrized file name * @param user user * @param date the date and time of the file generation * @param operationCode the code of the operation * @param hostingCode the canton of the operation * @param votersName the name of the voters group * @return the final file name */ public String injectParams(String pattern, String user, DateTime date, String operationCode, String hostingCode, String votersName) { String result = injectParams(pattern, user, date, operationCode, hostingCode); result = result.replace("{votersName}", votersName); return result; } /** * Resolves all the parameters. * * @param pattern parametrized file name * @param date the date and time of the file generation * @param operationCode the code of the operation * @param hostingCode the canton of the operation * @return the final file name */ public String injectParams(String pattern, DateTime date, String operationCode, String hostingCode) { return injectParams(pattern, getSystemUserName(), date, operationCode, hostingCode); } /** * Resolves all the parameters. * * @param pattern parametrized file name * @param date the date and time of the file generation * @param operationCode the code of the operation * @param hostingCode the canton of the operation * @param votersName the name of the voters group * @return the final file name */ public String injectParams(String pattern, DateTime date, String operationCode, String hostingCode, String votersName) { return injectParams(pattern, getSystemUserName(), date, operationCode, hostingCode, votersName); } /** * Tries to find a file matching a given <i>filenamePattern</i> regular expression. * * @param filenamePattern regular expression pattern that the file should match * @param rootPath path from which to recursively search for the file * @return the first file matching the pattern from the root directory, or an empty optional if none matched */ public Optional<Path> findFirstFileByPattern(final Pattern filenamePattern, Path rootPath) { try (Stream<Path> pathStream = Files.find(rootPath, FIND_FILES_MAX_DEPTH, (path, attr) -> filenamePattern.matcher(path.getFileName().toString()).matches())) { return pathStream.sorted().findFirst(); } catch (IOException e) { throw new FileOperationRuntimeException("Cannot walk file tree", e); } } private String getDateAsString(DateTime date) { return dateFormat.format(date.getMillis()); } private String getDateTimeAsString(DateTime date) { return datetimeFormat.format(date.getMillis()); } private static String getSystemUserName() { return System.getProperty("user.name"); } }