content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio.cli;
  
  import alluxio.exception.ExceptionMessage;
  import alluxio.exception.status.InvalidArgumentException;
  import alluxio.util.CommonUtils;
  
  import org.apache.commons.cli.CommandLine;
  import org.reflections.Reflections;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.IOException;
  import java.lang.reflect.Modifier;
  import java.nio.charset.StandardCharsets;
  import java.nio.file.Files;
  import java.nio.file.Paths;
  import java.text.MessageFormat;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import javax.annotation.Nullable;
  import javax.annotation.concurrent.ThreadSafe;
  
  /**
   * Class for convenience methods used by instances of {@link Command}.
   */
  @ThreadSafe
  public final class CommandUtils {
    private static final Logger LOG = LoggerFactory.getLogger(CommandUtils.class);
  
    private CommandUtils() {} // prevent instantiation
  
    /**
     * Get instances of all subclasses of {@link Command} in a sub-package called "command" the given
     * package.
     *
     * @param pkgName package prefix to look in
     * @param classArgs type of args to instantiate the class
     * @param objectArgs args to instantiate the class
     * @return a mapping from command name to command instance
     */
    public static Map<String, Command> loadCommands(String pkgName, Class[] classArgs,
        Object[] objectArgs) {
      Map<String, Command> commandsMap = new HashMap<>();
      Reflections reflections = new Reflections(Command.class.getPackage().getName());
      for (Class<? extends Command> cls : reflections.getSubTypesOf(Command.class)) {
        // Add commands from <pkgName>.command.*
        if (cls.getPackage().getName().equals(pkgName + ".command")
            && !Modifier.isAbstract(cls.getModifiers())) {
          // Only instantiate a concrete class
          Command cmd = CommonUtils.createNewClassInstance(cls, classArgs, objectArgs);
          commandsMap.put(cmd.getCommandName(), cmd);
        }
      }
      return commandsMap;
    }
  
    /**
     * Checks the number of non-option arguments equals n for command.
     *
     * @param cmd command instance
     * @param cl parsed commandline arguments
     * @param n an integer
     * @throws InvalidArgumentException if the number does not equal n
     */
    public static void checkNumOfArgsEquals(Command cmd, CommandLine cl, int n) throws
        InvalidArgumentException {
      if (cl.getArgs().length != n) {
        throw new InvalidArgumentException(ExceptionMessage.INVALID_ARGS_NUM
            .getMessage(cmd.getCommandName(), n, cl.getArgs().length));
      }
    }
  
    /**
     * Checks the number of non-option arguments is no less than n for command.
     *
     * @param cmd command instance
     * @param cl parsed commandline arguments
     * @param n an integer
     * @throws InvalidArgumentException if the number is smaller than n
     */
    public static void checkNumOfArgsNoLessThan(Command cmd, CommandLine cl, int n)
        throws InvalidArgumentException {
      if (cl.getArgs().length < n) {
        throw new InvalidArgumentException(
            MessageFormat.format("Command {0} requires at least {1} arguments ({2} provided)",
                cmd.getCommandName(), n, cl.getArgs().length));
      }
    }
  
    /**
     * Checks the number of non-option arguments is no more than n for command.
     *
     * @param cmd command instance
     * @param cl parsed commandline arguments
     * @param n an integer
     * @throws InvalidArgumentException if the number is greater than n
     */
    public static void checkNumOfArgsNoMoreThan(Command cmd, CommandLine cl, int n)
        throws InvalidArgumentException {
      if (cl.getArgs().length > n) {
        throw new InvalidArgumentException(
            MessageFormat.format("Command {0} requires at most {1} arguments ({2} provided)",
                cmd.getCommandName(), n, cl.getArgs().length));
      }
    }
  
    /**
     * Reads a list of nodes from given file name ignoring comments and empty lines.
     * Can be used to read conf/workers or conf/masters.
     * @param confDir directory that holds the configuration
     * @param fileName name of a file that contains the list of the nodes
     * @return list of the node names, null when file fails to read
     */
    @Nullable
    public static Set<String> readNodeList(String confDir, String fileName) {
      List<String> lines;
      String path = Paths.get(confDir, fileName).normalize().toString();
      try {
        lines = Files.readAllLines(Paths.get(confDir, fileName), StandardCharsets.UTF_8);
      } catch (IOException e) {
        System.err.format("Failed to read file %s/%s. Ignored.%n", confDir, fileName);
        return new HashSet<>();
      }
  
      Set<String> nodes = new HashSet<>();
      for (String line : lines) {
        String node = line.trim();
        if (node.startsWith("#") || node.length() == 0) {
          continue;
        }
        if (!nodes.add(node)) {
          System.out.format("Duplicate node hostname %s found in %s%n", node, path);
        }
      }
  
      return nodes;
    }
  }
  