Java tutorial
package net.sourceforge.squirrel_sql.client; /* * Copyright (C) 2001-2006 Colin Bell * colbell@users.sourceforge.net * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ import java.util.ArrayList; import java.util.Arrays; import java.util.Collections; import java.util.List; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.CommandLineParser; import org.apache.commons.cli.GnuParser; import org.apache.commons.cli.HelpFormatter; import org.apache.commons.cli.Option; import org.apache.commons.cli.OptionBuilder; import org.apache.commons.cli.Options; import org.apache.commons.cli.ParseException; /** * Application arguments. * * <B>Note:</B> <EM>This class <B>cannot</B> use the logging package as this * class is used to initialize the logging package. Nor can it use any classes * that themselves use the logging package.</EM> Since StringManager uses the * logging facility, neither can it be internationalized. * * @author <A HREF="mailto:colbell@users.sourceforge.net">Colin Bell</A> */ public class ApplicationArguments implements IApplicationArguments { /** * Option descriptions. * * <UL> * <LI>element 0 - short option * <LI>element 1 - long option (null if none) * <LI>element 2 - option description * </UL> */ public interface IOptions { String[] HELP = { "h", "help", "Display Help and exit" }; String[] SQUIRREL_HOME = { "home", "squirrel-home", "SQuirreL home directory" }; String[] LOG_FILE = { "l", "log-config-file", "Logging configuration file" }; String[] USE_DEFAULT_METAL_THEME = { "m", "use-default-metal-theme", "Use default metal theme" }; String[] USE_NATIVE_LAF = { "n", "native-laf", "Use native look and feel" }; String[] NO_PLUGINS = { "nop", "no-plugins", "Don't load plugins" }; String[] NO_SPLASH = { "nos", "no-splash", "Don't display splash screen" }; String[] USER_SETTINGS_DIR = { "userdir", "user-settings-dir", "User settings directory" }; String[] UI_DEBUG = { "uidebug", "user-interface-debugging", "Provides tool-tips and highlighting of UI components for easy identification" }; String[] PLUGIN_LIST = { "pluginlist", "plugin-classpath-list", "Specify a comma-delimited list of plugins to load from the CLASSPATH" }; String[] SHUTDOWN_TIMEOUT_SECONDS = { "s", "shutdown-timeout-seconds", "Specify the number of seconds to allow the application to run before exiting the VM" }; } /** Only instance of this class. */ private static volatile ApplicationArguments s_instance; /** Collection of possible options that acn be passed. */ private final Options _options = new Options(); /** Parsed command line that was passed to application. */ private CommandLine _cmdLine; /** "Raw" arguments straight from the command line. */ private String[] _rawArgs; /** Squirrels home directory. */ private String _squirrelHome = null; /** * If not <TT>null</TT> then is an override for the users .squirrel-sql * settings directory. */ private String _userSettingsDir = null; /** Path for logging configuration file */ private String _loggingConfigFile = null; /** List of plugins to load from the classloader */ private List<String> _pluginList = null; /** Time in seconds to allow the application to run prior to exiting the VM */ private Integer _shutdownTimerSeconds = null; /** * Ctor specifying arguments from command line. * * @param args Arguments passed on command line. * * @throws ParseException * Thrown if unable to parse arguments. */ private ApplicationArguments(String[] args) throws ParseException { super(); createOptions(); // set up array to return for public access to cmd line args _rawArgs = args; final CommandLineParser parser = new GnuParser(); try { _cmdLine = parser.parse(_options, args); } catch (ParseException ex) { System.err.println("Parsing failed. Reason: " + ex.getMessage()); printHelp(); throw ex; } if (_cmdLine.hasOption(IOptions.SQUIRREL_HOME[0])) { _squirrelHome = _cmdLine.getOptionValue(IOptions.SQUIRREL_HOME[0]); } if (_cmdLine.hasOption(IOptions.USER_SETTINGS_DIR[0])) { _userSettingsDir = _cmdLine.getOptionValue(IOptions.USER_SETTINGS_DIR[0]); } if (_cmdLine.hasOption(IOptions.LOG_FILE[0])) { _loggingConfigFile = _cmdLine.getOptionValue(IOptions.LOG_FILE[0]); } if (_cmdLine.hasOption(IOptions.PLUGIN_LIST[0])) { String pluginList = _cmdLine.getOptionValue(IOptions.PLUGIN_LIST[0]); if (pluginList != null && !pluginList.isEmpty()) { String[] pluginArr = pluginList.split(","); _pluginList = new ArrayList<String>(Arrays.asList(pluginArr)); _pluginList = Collections.unmodifiableList(_pluginList); } } if (_cmdLine.hasOption(IOptions.SHUTDOWN_TIMEOUT_SECONDS[0])) { _shutdownTimerSeconds = Integer.parseInt(_cmdLine.getOptionValue(IOptions.SHUTDOWN_TIMEOUT_SECONDS[0])); } } /** * Initialize application arguments. * * @param args Arguments passed on command line. * * @return <TT>true</TT> if arguments parsed successfully else * <TT>false<.TT>. If parsing was unsuccessful an error was written * to standard error. */ public synchronized static boolean initialize(String[] args) { if (s_instance == null) { try { s_instance = new ApplicationArguments(args); } catch (ParseException ex) { return false; } } else { System.out.println("ApplicationArguments.initialize() called twice"); } return true; } /** * Return the single instance of this class. * * @return the single instance of this class. If initialize() hasn't yet been called, then it is * assumed that there are no arguments to the application. */ public static ApplicationArguments getInstance() { if (s_instance == null) { try { s_instance = new ApplicationArguments(new String[] {}); } catch (ParseException e) { e.printStackTrace(); } } return s_instance; } /** * @see net.sourceforge.squirrel_sql.client.IApplicationArguments#getSquirrelHomeDirectory() */ public String getSquirrelHomeDirectory() { return _squirrelHome; } /** * @see net.sourceforge.squirrel_sql.client.IApplicationArguments#getUserSettingsDirectoryOverride() */ public String getUserSettingsDirectoryOverride() { return _userSettingsDir; } /** * @see net.sourceforge.squirrel_sql.client.IApplicationArguments#getShowSplashScreen() */ public boolean getShowSplashScreen() { return !_cmdLine.hasOption(IOptions.NO_SPLASH[0]); } /** * @see net.sourceforge.squirrel_sql.client.IApplicationArguments#getShowHelp() */ public boolean getShowHelp() { return _cmdLine.hasOption(IOptions.HELP[0]); } /** * @see net.sourceforge.squirrel_sql.client.IApplicationArguments#getLoggingConfigFileName() */ public String getLoggingConfigFileName() { return _loggingConfigFile; } /** * @see net.sourceforge.squirrel_sql.client.IApplicationArguments#getLoadPlugins() */ public boolean getLoadPlugins() { return !_cmdLine.hasOption(IOptions.NO_PLUGINS[0]); } /** * @see net.sourceforge.squirrel_sql.client.IApplicationArguments#useDefaultMetalTheme() */ public boolean useDefaultMetalTheme() { return _cmdLine.hasOption(IOptions.USE_DEFAULT_METAL_THEME[0]); } /** * @see net.sourceforge.squirrel_sql.client.IApplicationArguments#useNativeLAF() */ public boolean useNativeLAF() { return _cmdLine.hasOption(IOptions.USE_NATIVE_LAF[0]); } /** * @see net.sourceforge.squirrel_sql.client.IApplicationArguments#getRawArguments() */ public String[] getRawArguments() { return _rawArgs; } /** * @see net.sourceforge.squirrel_sql.client.IApplicationArguments#getUserInterfaceDebugEnabled() */ public boolean getUserInterfaceDebugEnabled() { return _cmdLine.hasOption(IOptions.UI_DEBUG[0]); } /** * @see net.sourceforge.squirrel_sql.client.IApplicationArguments#getPluginList() */ public List<String> getPluginList() { return _pluginList; } public Integer getShutdownTimerSeconds() { return _shutdownTimerSeconds; } void printHelp() { HelpFormatter formatter = new HelpFormatter(); formatter.printHelp("squirrel-sql", _options); } /** * Create the <TT>Options</TT> object used to parse the command line. */ private void createOptions() { Option opt; opt = createAnOption(IOptions.NO_SPLASH); _options.addOption(opt); opt = createAnOption(IOptions.HELP); _options.addOption(opt); opt = createAnOption(IOptions.NO_PLUGINS); _options.addOption(opt); opt = createAnOption(IOptions.USE_DEFAULT_METAL_THEME); _options.addOption(opt); opt = createAnOption(IOptions.USE_NATIVE_LAF); _options.addOption(opt); opt = createAnOptionWithArgument(IOptions.SQUIRREL_HOME); _options.addOption(opt); opt = createAnOptionWithArgument(IOptions.USER_SETTINGS_DIR); _options.addOption(opt); opt = createAnOptionWithArgument(IOptions.LOG_FILE); _options.addOption(opt); opt = createAnOption(IOptions.UI_DEBUG); _options.addOption(opt); opt = createAnOptionWithArgument(IOptions.PLUGIN_LIST); _options.addOption(opt); opt = createAnOptionWithArgument(IOptions.SHUTDOWN_TIMEOUT_SECONDS); _options.addOption(opt); } private Option createAnOption(String[] argInfo) { Option opt = new Option(argInfo[0], argInfo[2]); if (!isStringEmpty(argInfo[1])) { opt.setLongOpt(argInfo[1]); } return opt; } private Option createAnOptionWithArgument(String[] argInfo) { OptionBuilder.withArgName(argInfo[0]); OptionBuilder.hasArg(); OptionBuilder.withDescription(argInfo[2]); Option opt = OptionBuilder.create(argInfo[0]); if (!isStringEmpty(argInfo[1])) { opt.setLongOpt(argInfo[1]); } return opt; } private static boolean isStringEmpty(String str) { return str == null || str.length() == 0; } /** * Resets the internally stored instance so that the next call to initialize * will function as the first call. Useful for unit tests, so it uses package * level access. */ static final void reset() { s_instance = null; } }