content: /**
   * Licensed 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.aurora.common.base;
  
  import com.google.common.base.Preconditions;
  import com.google.common.collect.Iterables;
  
  import org.apache.commons.lang.StringUtils;
  
  /**
   * A utility helpful in concisely checking preconditions on arguments.  This utility is a complement
   * to {@link com.google.common.base.Preconditions}.
   *
   * @author John Sirois
   */
  public final class MorePreconditions {
  
    private static final String ARG_NOT_BLANK_MSG = "Argument cannot be blank";
  
    private MorePreconditions() {
      // utility
    }
  
    /**
     * Checks that a string is both non-null and non-empty.
     *
     * @see #checkNotBlank(String, String, Object...)
     */
    public static String checkNotBlank(String argument) {
      return checkNotBlank(argument, ARG_NOT_BLANK_MSG);
    }
  
    /**
     * Checks that a string is both non-null and non-empty.
     *
     * @param argument the argument to validate
     * @param message the message template for validation exception messages where %s serves as the
     *     sole argument placeholder
     * @param args any arguments needed by the message template
     * @return the argument if it is valid
     * @throws NullPointerException if the argument is null
     * @throws IllegalArgumentException if the argument is the empty string or a pure whitespace
     *    string
     */
    public static String checkNotBlank(String argument, String message, Object... args) {
      Preconditions.checkNotNull(argument, message, args);
      Preconditions.checkArgument(!StringUtils.isBlank(argument), message, args);
      return argument;
    }
  
    /**
     * Checks that an Iterable is both non-null and non-empty.  This method does not check individual
     * elements in the Iterable.
     *
     * @see #checkNotBlank(Iterable, String, Object...)
     */
    public static <S, T extends Iterable<S>> T checkNotBlank(T argument) {
      return checkNotBlank(argument, ARG_NOT_BLANK_MSG);
    }
  
    /**
     * Checks that an Iterable is both non-null and non-empty.  This method does not check individual
     * elements in the Iterable, it just checks that the Iterable has at least one element.
     *
     * @param argument the argument to validate
     * @param message the message template for validation exception messages where %s serves as the
     *     sole argument placeholder
     * @param args any arguments needed by the message template
     * @return the argument if it is valid
     * @throws NullPointerException if the argument is null
     * @throws IllegalArgumentException if the argument has no iterable elements
     */
    public static <S, T extends Iterable<S>> T checkNotBlank(T argument, String message,
        Object... args) {
      Preconditions.checkNotNull(argument, message, args);
      Preconditions.checkArgument(!Iterables.isEmpty(argument), message, args);
      return argument;
    }
  }
  