MorePreconditions.java

// =================================================================================================
// Copyright 2011 Twitter, Inc.
// -------------------------------------------------------------------------------------------------
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this work except in compliance with the License.
// You may obtain a copy of the License in the LICENSE file, or 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 com.twitter.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;
  }

  /**
   * Checks that a double falls within a specified range, inclusive
   *
   * @param argument argument to validate.
   * @param minimum minimum possible valid value for the argument.
   * @param maximum maximum possible valid value for the argument.
   * @param message the message template for validation exception messages where %s serves as the
   *                sole argument placeholder.
   * @return the argument if it is valid.
   * @throws IllegalArgumentException if the argument falls outside of the specified range.
   */
  public static double checkArgumentRange(double argument, double minimum, double maximum,
      String message) {
    Preconditions.checkArgument(minimum <= argument, message, argument);
    Preconditions.checkArgument(argument <= maximum, message, argument);
    return argument;
  }

  /**
   * Checks that an int falls within a specified range, inclusive
   *
   * @param argument argument to validate.
   * @param minimum minimum possible valid value for the argument.
   * @param maximum maximum possible valid value for the argument.
   * @param message the message template for validation exception messages where %s serves as the
   *                sole argument placeholder.
   * @return the argument if it is valid.
   * @throws IllegalArgumentException if the argument falls outside of the specified range.
   */
  public static int checkArgumentRange(int argument, int minimum, int maximum,
      String message) {
    Preconditions.checkArgument(minimum <= argument, message, argument);
    Preconditions.checkArgument(argument <= maximum, message, argument);
    return argument;
  }

  /**
   * Checks that at least one of the specified arguments is true.
   *
   * @param message the message for validation exception messages.
   * @param arguments one or more arguments to check.
   * @return true if at least one of the arguments is true.
   * @throws IllegalArgumentException if none of the arguments are true.
   */
  public static boolean checkArguments(String message,
      Boolean... arguments) {
    for (Boolean argument : arguments) {
      if (argument) {
        return true;
      }
    }
    throw new IllegalArgumentException(message);
  }
}