samza-sql-shell/src/main/java/org/apache/samza/sql/client/util/CliUtil.java

/*
 * 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.samza.sql.client.util;

import java.io.PrintWriter;
import org.apache.samza.sql.client.cli.CliCommand;

/**
 * Convenient utility class with static methods.
 */
public class CliUtil {
  public static boolean isNullOrEmpty(String str) {
    return str == null || str.isEmpty();
  }

  public static int ceilingDiv(int x, int y) {
    if (x < 0 || y <= 0)
      throw new IllegalArgumentException();

    return x / y + (x % y == 0 ? 0 : 1);
  }

  public static StringBuilder appendTo(StringBuilder builder, int toPos, char c) {
    for (int i = builder.length(); i <= toPos; ++i) {
      builder.append(c);
    }
    return builder;
  }

  /**
   * Trims: leading spaces; trailing spaces and ";"s
   * @param command input String to trim
   * @return trimmed String
   */
  public static String trimCommand(String command) {
    if (CliUtil.isNullOrEmpty(command))
      return command;

    int len = command.length();
    int st = 0;

    while ((st < len) && (command.charAt(st) <= ' ')) {
      st++;
    }
    while ((st < len) && ((command.charAt(len - 1) <= ' ')
        || command.charAt(len - 1) == ';')) {
      len--;
    }
    return ((st > 0) || (len < command.length())) ? command.substring(st, len) : command;
  }

  /**
   * Prints to input {@link PrintWriter} the usage string of the input {@link CliCommand}
   * @param command command to get its usage string
   * @param writer where to print usage
   */
  public static void printCommandUsage(CliCommand command, PrintWriter writer) {
    writer.println(command.getCommandType().getUsage());
    writer.flush();
  }
}