Java tutorial
/** * diqube: Distributed Query Base. * * Copyright (C) 2015 Bastian Gloeckle * * This file is part of diqube. * * diqube 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 Affero 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/>. */ package org.diqube.tool; import java.io.IOException; import java.util.Collection; import java.util.HashMap; import java.util.Map; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.google.common.reflect.ClassPath; import com.google.common.reflect.ClassPath.ClassInfo; /** * Main class of diqube tool, which provides command line functions for diqube. * * @author Bastian Gloeckle */ public class Tool implements ToolFunction { private static final String BASE_PKG = "org.diqube.tool"; private static final Logger logger = LoggerFactory.getLogger(Tool.class); public static void main(String[] args) throws IOException, InstantiationException, IllegalAccessException { Collection<ClassInfo> classInfos = ClassPath.from(Tool.class.getClassLoader()) .getTopLevelClassesRecursive(BASE_PKG); Map<String, ToolFunction> toolFunctions = new HashMap<>(); for (ClassInfo classInfo : classInfos) { Class<?> clazz = classInfo.load(); ToolFunctionName toolFunctionName = clazz.getAnnotation(ToolFunctionName.class); if (toolFunctionName != null) { ToolFunction functionInstance = (ToolFunction) clazz.newInstance(); toolFunctions.put(toolFunctionName.value(), functionInstance); } } new Tool(toolFunctions).execute(args); } private Map<String, ToolFunction> toolFunctions; private Tool(Map<String, ToolFunction> toolFunctions) { this.toolFunctions = toolFunctions; } @Override public void execute(String[] args) { if (args.length == 0 || !toolFunctions.containsKey(args[0])) { logger.error("No function name given or function unknown. Available functions: {}", toolFunctions.keySet()); System.out.println(); System.out.println("Copyright (C) 2015 Bastian Gloeckle"); System.out.println(); System.out.println( "diqube 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 Affero General Public License for more details."); System.out.println( "For source code and more information see http://diqube.org and http://github.com/diqube/diqube."); System.exit(1); return; } String[] remainingArgs = new String[args.length - 1]; for (int i = 0; i < args.length - 1; i++) remainingArgs[i] = args[i + 1]; toolFunctions.get(args[0]).execute(remainingArgs); } }