/*
    * 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.hadoop.hbase.util;
  
  import java.util.Set;
  import java.util.TreeSet;
  
  import org.apache.commons.cli.BasicParser;
  import org.apache.commons.cli.CommandLine;
  import org.apache.commons.cli.CommandLineParser;
  import org.apache.commons.cli.HelpFormatter;
  import org.apache.commons.cli.Options;
  import org.apache.commons.cli.ParseException;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.classification.InterfaceAudience;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.HBaseConfiguration;
  import org.apache.hadoop.util.Tool;
  import org.apache.hadoop.util.ToolRunner;
  
  /**
   * Common base class used for HBase command-line tools. Simplifies workflow and
   * command-line argument parsing.
   */
  @InterfaceAudience.Private
  public abstract class AbstractHBaseTool implements Tool {
  
    private static final int EXIT_SUCCESS = 0;
    private static final int EXIT_FAILURE = 1;
  
    private static final String SHORT_HELP_OPTION = "h";
    private static final String LONG_HELP_OPTION = "help";
  
    private static final Log LOG = LogFactory.getLog(AbstractHBaseTool.class);
  
    private final Options options = new Options();
  
    protected Configuration conf = null;
  
    private static final Set<String> requiredOptions = new TreeSet<String>();
  
    /**
     * Override this to add command-line options using {@link #addOptWithArg}
     * and similar methods.
     */
    protected abstract void addOptions();
  
    /**
     * This method is called to process the options after they have been parsed.
     */
    protected abstract void processOptions(CommandLine cmd);
  
    /** The "main function" of the tool */
    protected abstract int doWork() throws Exception;
  
    @Override
    public Configuration getConf() {
      return conf;
    }
  
    @Override
    public void setConf(Configuration conf) {
      this.conf = conf;
    }
  
    @Override
    public final int run(String[] args) throws Exception {
      if (conf == null) {
        LOG.error("Tool configuration is not initialized");
        throw new NullPointerException("conf");
      }
  
      CommandLine cmd;
      try {
        // parse the command line arguments
        cmd = parseArgs(args);
      } catch (ParseException e) {
        LOG.error("Error when parsing command-line arguemnts", e);
        printUsage();
        return EXIT_FAILURE;
      }
  
      if (cmd.hasOption(SHORT_HELP_OPTION) || cmd.hasOption(LONG_HELP_OPTION) ||
          !sanityCheckOptions(cmd)) {
       printUsage();
       return EXIT_FAILURE;
     }
 
     processOptions(cmd);
 
     int ret = EXIT_FAILURE;
     try {
       ret = doWork();
     } catch (Exception e) {
       LOG.error("Error running command-line tool", e);
       return EXIT_FAILURE;
     }
     return ret;
   }
 
   private boolean sanityCheckOptions(CommandLine cmd) {
     boolean success = true;
     for (String reqOpt : requiredOptions) {
       if (!cmd.hasOption(reqOpt)) {
         LOG.error("Required option -" + reqOpt + " is missing");
         success = false;
       }
     }
     return success;
   }
 
   private CommandLine parseArgs(String[] args) throws ParseException {
     options.addOption(SHORT_HELP_OPTION, LONG_HELP_OPTION, false, "Show usage");
     addOptions();
     CommandLineParser parser = new BasicParser();
     return parser.parse(options, args);
   }
 
   private void printUsage() {
     HelpFormatter helpFormatter = new HelpFormatter();
     helpFormatter.setWidth(80);
     String usageHeader = "Options:";
     String usageFooter = "";
     String usageStr = "bin/hbase " + getClass().getName() + " <options>";
 
     helpFormatter.printHelp(usageStr, usageHeader, options,
         usageFooter);
   }
 
   protected void addRequiredOptWithArg(String opt, String description) {
     requiredOptions.add(opt);
     addOptWithArg(opt, description);
   }
 
   protected void addOptNoArg(String opt, String description) {
     options.addOption(opt, false, description);
   }
 
   protected void addOptNoArg(String shortOpt, String longOpt, String description) {
     options.addOption(shortOpt, longOpt, false, description);
   }
 
   protected void addOptWithArg(String opt, String description) {
     options.addOption(opt, true, description);
   }
 
   protected void addOptWithArg(String shortOpt, String longOpt, String description) {
     options.addOption(shortOpt, longOpt, true, description);
   }
 
   /**
    * Parse a number and enforce a range.
    */
   public static long parseLong(String s, long minValue, long maxValue) {
     long l = Long.parseLong(s);
     if (l < minValue || l > maxValue) {
       throw new IllegalArgumentException("The value " + l
           + " is out of range [" + minValue + ", " + maxValue + "]");
     }
     return l;
   }
 
   public static int parseInt(String s, int minValue, int maxValue) {
     return (int) parseLong(s, minValue, maxValue);
   }
 
   /** Call this from the concrete tool class's main function. */
   protected void doStaticMain(String args[]) {
     int ret;
     try {
       ret = ToolRunner.run(HBaseConfiguration.create(), this, args);
     } catch (Exception ex) {
       LOG.error("Error running command-line tool", ex);
       ret = EXIT_FAILURE;
     }
     System.exit(ret);
   }
 
 }