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.gobblin.cluster; import java.io.PrintWriter; import java.util.Map; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.DefaultParser; import org.apache.commons.cli.HelpFormatter; import org.apache.commons.cli.Option; import org.apache.commons.cli.Options; import org.apache.commons.cli.ParseException; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.google.common.collect.ImmutableMap; class SingleTaskRunnerMainOptions { private static final Logger logger = LoggerFactory.getLogger(SingleTaskRunnerMainOptions.class); static final String CLUSTER_CONFIG_FILE_PATH = "cluster_config_file_path"; static final String WORK_UNIT_FILE_PATH = "work_unit_file_path"; static final String JOB_ID = "job_id"; private static final ImmutableMap<String, String> OPTIONS_MAP = ImmutableMap.of(JOB_ID, "job id", WORK_UNIT_FILE_PATH, "work unit file path", CLUSTER_CONFIG_FILE_PATH, "cluster configuration file path"); private static final int CHARACTERS_PER_LINE = 80; private final PrintWriter writer; private CommandLine cmd; private Options options; SingleTaskRunnerMainOptions(final String[] args, final PrintWriter writer) { this.writer = writer; initCmdLineOptions(args); } private void initCmdLineOptions(final String[] args) { this.options = buildExpectedOptions(); try { this.cmd = new DefaultParser().parse(this.options, args); } catch (final ParseException e) { logger.error("failed to parse command options.", e); printUsage(this.options); throw new GobblinClusterException("Failed to parse command line options", e); } } private Options buildExpectedOptions() { final Options options = new Options(); for (final Map.Entry<String, String> entry : OPTIONS_MAP.entrySet()) { final Option option = Option.builder(null).required(true).longOpt(entry.getKey()).desc(entry.getValue()) .hasArg().build(); options.addOption(option); } return options; } private void printUsage(final Options options) { final HelpFormatter formatter = new HelpFormatter(); formatter.printUsage(this.writer, CHARACTERS_PER_LINE, SingleTaskRunnerMain.class.getSimpleName(), options); } String getJobId() { return this.cmd.getOptionValue(JOB_ID); } String getWorkUnitFilePath() { return this.cmd.getOptionValue(WORK_UNIT_FILE_PATH); } String getClusterConfigFilePath() { return this.cmd.getOptionValue(CLUSTER_CONFIG_FILE_PATH); } }