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.bookkeeper.tools.framework; import com.google.common.base.Strings; /** * A command group that group commands together. They share same global flags. */ public abstract class CliCommandGroup<GlobalFlagsT extends CliFlags> extends CliCommand<GlobalFlagsT, GlobalFlagsT> implements CommandGroup<GlobalFlagsT> { @SuppressWarnings("unchecked") private static <GlobalFlagsT extends CliFlags> CliSpec<GlobalFlagsT> updateSpec(CliSpec<GlobalFlagsT> spec) { CliSpec<GlobalFlagsT> newSpec; if (Strings.isNullOrEmpty(spec.usage())) { newSpec = CliSpec.newBuilder(spec) .withUsage(String.format("%s %s [command] [command options]", spec.parent(), spec.name())) .withFlags(null).build(); } else { newSpec = CliSpec.newBuilder(spec).withFlags(null).build(); } String path = newSpec.parent() + " " + newSpec.name(); for (Command<GlobalFlagsT> cmd : newSpec.commands()) { if (cmd instanceof CliCommand) { CliCommand<GlobalFlagsT, GlobalFlagsT> cliCmd = (CliCommand<GlobalFlagsT, GlobalFlagsT>) cmd; cliCmd.setParent(path); } } return newSpec; } protected CliCommandGroup(CliSpec<GlobalFlagsT> spec) { super(updateSpec(spec)); } @Override public Boolean apply(GlobalFlagsT globalFlags, String[] args) { CliSpec<GlobalFlagsT> newSpec = CliSpec.newBuilder(spec).withFlags(globalFlags).setCommandGroup(true) .build(); return 0 == Cli.runCli(newSpec, args); } @Override public void usage() { CliSpec<GlobalFlagsT> newSpec = CliSpec.newBuilder(spec).setCommandGroup(true).build(); // run with "empty args", which will print the usage for this command group. Cli.printUsage(newSpec); } }