content: /*
   * Copyright (C) 2012 The Guava Authors
   *
   * 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 com.aliyun.hitsdb.client.util.guava.base;
  
  /**
   * The implementation of Ticker is derived from the Preconditions class of Guava 16.0,
   * which is licensed under the Apache License 2.0
   */
  public final class Preconditions {
      private Preconditions() {}
  
      /**
       * Ensures the truth of an expression involving one or more parameters to the calling method.
       *
       * @param expression a boolean expression
       * @throws IllegalArgumentException if {@code expression} is false
       */
      public static void checkArgument(boolean expression) {
          if (!expression) {
              throw new IllegalArgumentException();
          }
      }
  
      /**
       * Ensures the truth of an expression involving one or more parameters to the calling method.
       *
       * @param expression a boolean expression
       * @param errorMessage the exception message to use if the check fails; will be converted to a
       *     string using {@link String#valueOf(Object)}
       * @throws IllegalArgumentException if {@code expression} is false
       */
      public static void checkArgument(boolean expression, Object errorMessage) {
          if (!expression) {
              throw new IllegalArgumentException(String.valueOf(errorMessage));
          }
      }
  
      /**
       * Ensures the truth of an expression involving one or more parameters to the calling method.
       *
       * @param expression a boolean expression
       * @param errorMessageTemplate a template for the exception message should the check fail. The
       *     message is formed by replacing each {@code %s} placeholder in the template with an
       *     argument. These are matched by position - the first {@code %s} gets {@code
       *     errorMessageArgs[0]}, etc.  Unmatched arguments will be appended to the formatted message
       *     in square braces. Unmatched placeholders will be left as-is.
       * @param errorMessageArgs the arguments to be substituted into the message template. Arguments
       *     are converted to strings using {@link String#valueOf(Object)}.
       * @throws IllegalArgumentException if {@code expression} is false
       * @throws NullPointerException if the check fails and either {@code errorMessageTemplate} or
       *     {@code errorMessageArgs} is null (don't let this happen)
       */
      public static void checkArgument(boolean expression,
                                       String errorMessageTemplate,
                                       Object... errorMessageArgs) {
          if (!expression) {
              throw new IllegalArgumentException(format(errorMessageTemplate, errorMessageArgs));
          }
      }
  
      /**
       * Substitutes each {@code %s} in {@code template} with an argument. These are matched by
       * position: the first {@code %s} gets {@code args[0]}, etc.  If there are more arguments than
       * placeholders, the unmatched arguments will be appended to the end of the formatted message in
       * square braces.
       *
       * @param template a non-null string containing 0 or more {@code %s} placeholders.
       * @param args the arguments to be substituted into the message template. Arguments are converted
       *     to strings using {@link String#valueOf(Object)}. Arguments can be null.
       */
      // Note that this is somewhat-improperly used from Verify.java as well.
      static String format(String template, Object... args) {
          template = String.valueOf(template); // null -> "null"
  
          // start substituting the arguments into the '%s' placeholders
          StringBuilder builder = new StringBuilder(template.length() + 16 * args.length);
          int templateStart = 0;
          int i = 0;
          while (i < args.length) {
              int placeholderStart = template.indexOf("%s", templateStart);
              if (placeholderStart == -1) {
                  break;
              }
              builder.append(template.substring(templateStart, placeholderStart));
              builder.append(args[i++]);
              templateStart = placeholderStart + 2;
          }
          builder.append(template.substring(templateStart));
  
          // if we run out of placeholders, append the extra args in square braces
          if (i < args.length) {
              builder.append(" [");
              builder.append(args[i++]);
              while (i < args.length) {
                  builder.append(", ");
                  builder.append(args[i++]);
              }
              builder.append(']');
          }
  
          return builder.toString();
      }
  }
  