Source code

001/*
002 * Copyright (C) 2007 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
005 * in compliance with the License. You may obtain a copy of the License at
006 *
007 * http://www.apache.org/licenses/LICENSE-2.0
008 *
009 * Unless required by applicable law or agreed to in writing, software distributed under the License
010 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
011 * or implied. See the License for the specific language governing permissions and limitations under
012 * the License.
013 */
014
015package com.google.common.base;
016
017import static com.google.common.base.Strings.lenientFormat;
018
019import com.google.common.annotations.GwtCompatible;
020import com.google.errorprone.annotations.CanIgnoreReturnValue;
021import javax.annotation.CheckForNull;
022import org.checkerframework.checker.nullness.qual.Nullable;
023
024/**
025 * Static convenience methods that help a method or constructor check whether it was invoked
026 * correctly (that is, whether its <i>preconditions</i> were met).
027 *
028 * <p>If the precondition is not met, the {@code Preconditions} method throws an unchecked exception
029 * of a specified type, which helps the method in which the exception was thrown communicate that
030 * its caller has made a mistake. This allows constructs such as
031 *
032 * <pre>{@code
033 * public static double sqrt(double value) {
034 *   if (value < 0) {
035 *     throw new IllegalArgumentException("input is negative: " + value);
036 *   }
037 *   // calculate square root
038 * }
039 * }</pre>
040 *
041 * <p>to be replaced with the more compact
042 *
043 * <pre>{@code
044 * public static double sqrt(double value) {
045 *   checkArgument(value >= 0, "input is negative: %s", value);
046 *   // calculate square root
047 * }
048 * }</pre>
049 *
050 * <p>so that a hypothetical bad caller of this method, such as:
051 *
052 * <pre>{@code
053 * void exampleBadCaller() {
054 *   double d = sqrt(-1.0);
055 * }
056 * }</pre>
057 *
058 * <p>would be flagged as having called {@code sqrt()} with an illegal argument.
059 *
060 * <h3>Performance</h3>
061 *
062 * <p>Avoid passing message arguments that are expensive to compute; your code will always compute
063 * them, even though they usually won't be needed. If you have such arguments, use the conventional
064 * if/throw idiom instead.
065 *
066 * <p>Depending on your message arguments, memory may be allocated for boxing and varargs array
067 * creation. However, the methods of this class have a large number of overloads that prevent such
068 * allocations in many common cases.
069 *
070 * <p>The message string is not formatted unless the exception will be thrown, so the cost of the
071 * string formatting itself should not be a concern.
072 *
073 * <p>As with any performance concerns, you should consider profiling your code (in a production
074 * environment if possible) before spending a lot of effort on tweaking a particular element.
075 *
076 * <h3>Other types of preconditions</h3>
077 *
078 * <p>Not every type of precondition failure is supported by these methods. Continue to throw
079 * standard JDK exceptions such as {@link java.util.NoSuchElementException} or {@link
080 * UnsupportedOperationException} in the situations they are intended for.
081 *
082 * <h3>Non-preconditions</h3>
083 *
084 * <p>It is of course possible to use the methods of this class to check for invalid conditions
085 * which are <i>not the caller's fault</i>. Doing so is <b>not recommended</b> because it is
086 * misleading to future readers of the code and of stack traces. See <a
087 * href="https://github.com/google/guava/wiki/ConditionalFailuresExplained">Conditional failures
088 * explained</a> in the Guava User Guide for more advice. Notably, {@link Verify} offers assertions
089 * similar to those in this class for non-precondition checks.
090 *
091 * <h3>{@code java.util.Objects.requireNonNull()}</h3>
092 *
093 * <p>Projects which use {@code com.google.common} should generally avoid the use of {@link
094 * java.util.Objects#requireNonNull(Object)}. Instead, use whichever of {@link
095 * #checkNotNull(Object)} or {@link Verify#verifyNotNull(Object)} is appropriate to the situation.
096 * (The same goes for the message-accepting overloads.)
097 *
098 * <h3>Only {@code %s} is supported</h3>
099 *
100 * <p>{@code Preconditions} uses {@link Strings#lenientFormat} to format error message template
101 * strings. This only supports the {@code "%s"} specifier, not the full range of {@link
102 * java.util.Formatter} specifiers. However, note that if the number of arguments does not match the
103 * number of occurrences of {@code "%s"} in the format string, {@code Preconditions} will still
104 * behave as expected, and will still include all argument values in the error message; the message
105 * will simply not be formatted exactly as intended.
106 *
107 * <h3>More information</h3>
108 *
109 * <p>See the Guava User Guide on <a
110 * href="https://github.com/google/guava/wiki/PreconditionsExplained">using {@code
111 * Preconditions}</a>.
112 *
113 * @author Kevin Bourrillion
114 * @since 2.0
115 */
116@GwtCompatible
117@ElementTypesAreNonnullByDefault
118public final class Preconditions {
119  private Preconditions() {}
120
121  /**
122   * Ensures the truth of an expression involving one or more parameters to the calling method.
123   *
124   * @param expression a boolean expression
125   * @throws IllegalArgumentException if {@code expression} is false
126   */
127  public static void checkArgument(boolean expression) {
128    if (!expression) {
129      throw new IllegalArgumentException();
130    }
131  }
132
133  /**
134   * Ensures the truth of an expression involving one or more parameters to the calling method.
135   *
136   * @param expression a boolean expression
137   * @param errorMessage the exception message to use if the check fails; will be converted to a
138   *     string using {@link String#valueOf(Object)}
139   * @throws IllegalArgumentException if {@code expression} is false
140   */
141  public static void checkArgument(boolean expression, @CheckForNull Object errorMessage) {
142    if (!expression) {
143      throw new IllegalArgumentException(String.valueOf(errorMessage));
144    }
145  }
146
147  /**
148   * Ensures the truth of an expression involving one or more parameters to the calling method.
149   *
150   * @param expression a boolean expression
151   * @param errorMessageTemplate a template for the exception message should the check fail. The
152   *     message is formed by replacing each {@code %s} placeholder in the template with an
153   *     argument. These are matched by position - the first {@code %s} gets {@code
154   *     errorMessageArgs[0]}, etc. Unmatched arguments will be appended to the formatted message in
155   *     square braces. Unmatched placeholders will be left as-is.
156   * @param errorMessageArgs the arguments to be substituted into the message template. Arguments
157   *     are converted to strings using {@link String#valueOf(Object)}.
158   * @throws IllegalArgumentException if {@code expression} is false
159   */
160  public static void checkArgument(
161      boolean expression,
162      String errorMessageTemplate,
163      @CheckForNull @Nullable Object... errorMessageArgs) {
164    if (!expression) {
165      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, errorMessageArgs));
166    }
167  }
168
169  /**
170   * Ensures the truth of an expression involving one or more parameters to the calling method.
171   *
172   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
173   *
174   * @since 20.0 (varargs overload since 2.0)
175   */
176  public static void checkArgument(boolean expression, String errorMessageTemplate, char p1) {
177    if (!expression) {
178      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1));
179    }
180  }
181
182  /**
183   * Ensures the truth of an expression involving one or more parameters to the calling method.
184   *
185   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
186   *
187   * @since 20.0 (varargs overload since 2.0)
188   */
189  public static void checkArgument(boolean expression, String errorMessageTemplate, int p1) {
190    if (!expression) {
191      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1));
192    }
193  }
194
195  /**
196   * Ensures the truth of an expression involving one or more parameters to the calling method.
197   *
198   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
199   *
200   * @since 20.0 (varargs overload since 2.0)
201   */
202  public static void checkArgument(boolean expression, String errorMessageTemplate, long p1) {
203    if (!expression) {
204      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1));
205    }
206  }
207
208  /**
209   * Ensures the truth of an expression involving one or more parameters to the calling method.
210   *
211   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
212   *
213   * @since 20.0 (varargs overload since 2.0)
214   */
215  public static void checkArgument(
216      boolean expression, String errorMessageTemplate, @CheckForNull Object p1) {
217    if (!expression) {
218      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1));
219    }
220  }
221
222  /**
223   * Ensures the truth of an expression involving one or more parameters to the calling method.
224   *
225   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
226   *
227   * @since 20.0 (varargs overload since 2.0)
228   */
229  public static void checkArgument(
230      boolean expression, String errorMessageTemplate, char p1, char p2) {
231    if (!expression) {
232      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1, p2));
233    }
234  }
235
236  /**
237   * Ensures the truth of an expression involving one or more parameters to the calling method.
238   *
239   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
240   *
241   * @since 20.0 (varargs overload since 2.0)
242   */
243  public static void checkArgument(
244      boolean expression, String errorMessageTemplate, char p1, int p2) {
245    if (!expression) {
246      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1, p2));
247    }
248  }
249
250  /**
251   * Ensures the truth of an expression involving one or more parameters to the calling method.
252   *
253   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
254   *
255   * @since 20.0 (varargs overload since 2.0)
256   */
257  public static void checkArgument(
258      boolean expression, String errorMessageTemplate, char p1, long p2) {
259    if (!expression) {
260      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1, p2));
261    }
262  }
263
264  /**
265   * Ensures the truth of an expression involving one or more parameters to the calling method.
266   *
267   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
268   *
269   * @since 20.0 (varargs overload since 2.0)
270   */
271  public static void checkArgument(
272      boolean expression, String errorMessageTemplate, char p1, @CheckForNull Object p2) {
273    if (!expression) {
274      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1, p2));
275    }
276  }
277
278  /**
279   * Ensures the truth of an expression involving one or more parameters to the calling method.
280   *
281   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
282   *
283   * @since 20.0 (varargs overload since 2.0)
284   */
285  public static void checkArgument(
286      boolean expression, String errorMessageTemplate, int p1, char p2) {
287    if (!expression) {
288      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1, p2));
289    }
290  }
291
292  /**
293   * Ensures the truth of an expression involving one or more parameters to the calling method.
294   *
295   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
296   *
297   * @since 20.0 (varargs overload since 2.0)
298   */
299  public static void checkArgument(
300      boolean expression, String errorMessageTemplate, int p1, int p2) {
301    if (!expression) {
302      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1, p2));
303    }
304  }
305
306  /**
307   * Ensures the truth of an expression involving one or more parameters to the calling method.
308   *
309   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
310   *
311   * @since 20.0 (varargs overload since 2.0)
312   */
313  public static void checkArgument(
314      boolean expression, String errorMessageTemplate, int p1, long p2) {
315    if (!expression) {
316      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1, p2));
317    }
318  }
319
320  /**
321   * Ensures the truth of an expression involving one or more parameters to the calling method.
322   *
323   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
324   *
325   * @since 20.0 (varargs overload since 2.0)
326   */
327  public static void checkArgument(
328      boolean expression, String errorMessageTemplate, int p1, @CheckForNull Object p2) {
329    if (!expression) {
330      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1, p2));
331    }
332  }
333
334  /**
335   * Ensures the truth of an expression involving one or more parameters to the calling method.
336   *
337   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
338   *
339   * @since 20.0 (varargs overload since 2.0)
340   */
341  public static void checkArgument(
342      boolean expression, String errorMessageTemplate, long p1, char p2) {
343    if (!expression) {
344      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1, p2));
345    }
346  }
347
348  /**
349   * Ensures the truth of an expression involving one or more parameters to the calling method.
350   *
351   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
352   *
353   * @since 20.0 (varargs overload since 2.0)
354   */
355  public static void checkArgument(
356      boolean expression, String errorMessageTemplate, long p1, int p2) {
357    if (!expression) {
358      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1, p2));
359    }
360  }
361
362  /**
363   * Ensures the truth of an expression involving one or more parameters to the calling method.
364   *
365   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
366   *
367   * @since 20.0 (varargs overload since 2.0)
368   */
369  public static void checkArgument(
370      boolean expression, String errorMessageTemplate, long p1, long p2) {
371    if (!expression) {
372      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1, p2));
373    }
374  }
375
376  /**
377   * Ensures the truth of an expression involving one or more parameters to the calling method.
378   *
379   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
380   *
381   * @since 20.0 (varargs overload since 2.0)
382   */
383  public static void checkArgument(
384      boolean expression, String errorMessageTemplate, long p1, @CheckForNull Object p2) {
385    if (!expression) {
386      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1, p2));
387    }
388  }
389
390  /**
391   * Ensures the truth of an expression involving one or more parameters to the calling method.
392   *
393   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
394   *
395   * @since 20.0 (varargs overload since 2.0)
396   */
397  public static void checkArgument(
398      boolean expression, String errorMessageTemplate, @CheckForNull Object p1, char p2) {
399    if (!expression) {
400      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1, p2));
401    }
402  }
403
404  /**
405   * Ensures the truth of an expression involving one or more parameters to the calling method.
406   *
407   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
408   *
409   * @since 20.0 (varargs overload since 2.0)
410   */
411  public static void checkArgument(
412      boolean expression, String errorMessageTemplate, @CheckForNull Object p1, int p2) {
413    if (!expression) {
414      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1, p2));
415    }
416  }
417
418  /**
419   * Ensures the truth of an expression involving one or more parameters to the calling method.
420   *
421   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
422   *
423   * @since 20.0 (varargs overload since 2.0)
424   */
425  public static void checkArgument(
426      boolean expression, String errorMessageTemplate, @CheckForNull Object p1, long p2) {
427    if (!expression) {
428      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1, p2));
429    }
430  }
431
432  /**
433   * Ensures the truth of an expression involving one or more parameters to the calling method.
434   *
435   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
436   *
437   * @since 20.0 (varargs overload since 2.0)
438   */
439  public static void checkArgument(
440      boolean expression,
441      String errorMessageTemplate,
442      @CheckForNull Object p1,
443      @CheckForNull Object p2) {
444    if (!expression) {
445      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1, p2));
446    }
447  }
448
449  /**
450   * Ensures the truth of an expression involving one or more parameters to the calling method.
451   *
452   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
453   *
454   * @since 20.0 (varargs overload since 2.0)
455   */
456  public static void checkArgument(
457      boolean expression,
458      String errorMessageTemplate,
459      @CheckForNull Object p1,
460      @CheckForNull Object p2,
461      @CheckForNull Object p3) {
462    if (!expression) {
463      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1, p2, p3));
464    }
465  }
466
467  /**
468   * Ensures the truth of an expression involving one or more parameters to the calling method.
469   *
470   * <p>See {@link #checkArgument(boolean, String, Object...)} for details.
471   *
472   * @since 20.0 (varargs overload since 2.0)
473   */
474  public static void checkArgument(
475      boolean expression,
476      String errorMessageTemplate,
477      @CheckForNull Object p1,
478      @CheckForNull Object p2,
479      @CheckForNull Object p3,
480      @CheckForNull Object p4) {
481    if (!expression) {
482      throw new IllegalArgumentException(lenientFormat(errorMessageTemplate, p1, p2, p3, p4));
483    }
484  }
485
486  /**
487   * Ensures the truth of an expression involving the state of the calling instance, but not
488   * involving any parameters to the calling method.
489   *
490   * @param expression a boolean expression
491   * @throws IllegalStateException if {@code expression} is false
492   * @see Verify#verify Verify.verify()
493   */
494  public static void checkState(boolean expression) {
495    if (!expression) {
496      throw new IllegalStateException();
497    }
498  }
499
500  /**
501   * Ensures the truth of an expression involving the state of the calling instance, but not
502   * involving any parameters to the calling method.
503   *
504   * @param expression a boolean expression
505   * @param errorMessage the exception message to use if the check fails; will be converted to a
506   *     string using {@link String#valueOf(Object)}
507   * @throws IllegalStateException if {@code expression} is false
508   * @see Verify#verify Verify.verify()
509   */
510  public static void checkState(boolean expression, @CheckForNull Object errorMessage) {
511    if (!expression) {
512      throw new IllegalStateException(String.valueOf(errorMessage));
513    }
514  }
515
516  /**
517   * Ensures the truth of an expression involving the state of the calling instance, but not
518   * involving any parameters to the calling method.
519   *
520   * @param expression a boolean expression
521   * @param errorMessageTemplate a template for the exception message should the check fail. The
522   *     message is formed by replacing each {@code %s} placeholder in the template with an
523   *     argument. These are matched by position - the first {@code %s} gets {@code
524   *     errorMessageArgs[0]}, etc. Unmatched arguments will be appended to the formatted message in
525   *     square braces. Unmatched placeholders will be left as-is.
526   * @param errorMessageArgs the arguments to be substituted into the message template. Arguments
527   *     are converted to strings using {@link String#valueOf(Object)}.
528   * @throws IllegalStateException if {@code expression} is false
529   * @see Verify#verify Verify.verify()
530   */
531  public static void checkState(
532      boolean expression,
533      /*
534       * TODO(cpovirk): Consider removing @CheckForNull here, as we've done with the other methods'
535       * errorMessageTemplate parameters: It is unlikely that callers intend for their string
536       * template to be null (though we do handle that case gracefully at runtime). I've left this
537       * one as it is because one of our users has defined a wrapper API around Preconditions,
538       * declaring a checkState method that accepts a possibly null template. So we'd need to update
539       * that user first.
540       */
541      @CheckForNull String errorMessageTemplate,
542      @CheckForNull @Nullable Object... errorMessageArgs) {
543    if (!expression) {
544      throw new IllegalStateException(lenientFormat(errorMessageTemplate, errorMessageArgs));
545    }
546  }
547
548  /**
549   * Ensures the truth of an expression involving the state of the calling instance, but not
550   * involving any parameters to the calling method.
551   *
552   * <p>See {@link #checkState(boolean, String, Object...)} for details.
553   *
554   * @since 20.0 (varargs overload since 2.0)
555   */
556  public static void checkState(boolean expression, String errorMessageTemplate, char p1) {
557    if (!expression) {
558      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1));
559    }
560  }
561
562  /**
563   * Ensures the truth of an expression involving the state of the calling instance, but not
564   * involving any parameters to the calling method.
565   *
566   * <p>See {@link #checkState(boolean, String, Object...)} for details.
567   *
568   * @since 20.0 (varargs overload since 2.0)
569   */
570  public static void checkState(boolean expression, String errorMessageTemplate, int p1) {
571    if (!expression) {
572      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1));
573    }
574  }
575
576  /**
577   * Ensures the truth of an expression involving the state of the calling instance, but not
578   * involving any parameters to the calling method.
579   *
580   * <p>See {@link #checkState(boolean, String, Object...)} for details.
581   *
582   * @since 20.0 (varargs overload since 2.0)
583   */
584  public static void checkState(boolean expression, String errorMessageTemplate, long p1) {
585    if (!expression) {
586      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1));
587    }
588  }
589
590  /**
591   * Ensures the truth of an expression involving the state of the calling instance, but not
592   * involving any parameters to the calling method.
593   *
594   * <p>See {@link #checkState(boolean, String, Object...)} for details.
595   *
596   * @since 20.0 (varargs overload since 2.0)
597   */
598  public static void checkState(
599      boolean expression, String errorMessageTemplate, @CheckForNull Object p1) {
600    if (!expression) {
601      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1));
602    }
603  }
604
605  /**
606   * Ensures the truth of an expression involving the state of the calling instance, but not
607   * involving any parameters to the calling method.
608   *
609   * <p>See {@link #checkState(boolean, String, Object...)} for details.
610   *
611   * @since 20.0 (varargs overload since 2.0)
612   */
613  public static void checkState(boolean expression, String errorMessageTemplate, char p1, char p2) {
614    if (!expression) {
615      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1, p2));
616    }
617  }
618
619  /**
620   * Ensures the truth of an expression involving the state of the calling instance, but not
621   * involving any parameters to the calling method.
622   *
623   * <p>See {@link #checkState(boolean, String, Object...)} for details.
624   *
625   * @since 20.0 (varargs overload since 2.0)
626   */
627  public static void checkState(boolean expression, String errorMessageTemplate, char p1, int p2) {
628    if (!expression) {
629      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1, p2));
630    }
631  }
632
633  /**
634   * Ensures the truth of an expression involving the state of the calling instance, but not
635   * involving any parameters to the calling method.
636   *
637   * <p>See {@link #checkState(boolean, String, Object...)} for details.
638   *
639   * @since 20.0 (varargs overload since 2.0)
640   */
641  public static void checkState(boolean expression, String errorMessageTemplate, char p1, long p2) {
642    if (!expression) {
643      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1, p2));
644    }
645  }
646
647  /**
648   * Ensures the truth of an expression involving the state of the calling instance, but not
649   * involving any parameters to the calling method.
650   *
651   * <p>See {@link #checkState(boolean, String, Object...)} for details.
652   *
653   * @since 20.0 (varargs overload since 2.0)
654   */
655  public static void checkState(
656      boolean expression, String errorMessageTemplate, char p1, @CheckForNull Object p2) {
657    if (!expression) {
658      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1, p2));
659    }
660  }
661
662  /**
663   * Ensures the truth of an expression involving the state of the calling instance, but not
664   * involving any parameters to the calling method.
665   *
666   * <p>See {@link #checkState(boolean, String, Object...)} for details.
667   *
668   * @since 20.0 (varargs overload since 2.0)
669   */
670  public static void checkState(boolean expression, String errorMessageTemplate, int p1, char p2) {
671    if (!expression) {
672      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1, p2));
673    }
674  }
675
676  /**
677   * Ensures the truth of an expression involving the state of the calling instance, but not
678   * involving any parameters to the calling method.
679   *
680   * <p>See {@link #checkState(boolean, String, Object...)} for details.
681   *
682   * @since 20.0 (varargs overload since 2.0)
683   */
684  public static void checkState(boolean expression, String errorMessageTemplate, int p1, int p2) {
685    if (!expression) {
686      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1, p2));
687    }
688  }
689
690  /**
691   * Ensures the truth of an expression involving the state of the calling instance, but not
692   * involving any parameters to the calling method.
693   *
694   * <p>See {@link #checkState(boolean, String, Object...)} for details.
695   *
696   * @since 20.0 (varargs overload since 2.0)
697   */
698  public static void checkState(boolean expression, String errorMessageTemplate, int p1, long p2) {
699    if (!expression) {
700      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1, p2));
701    }
702  }
703
704  /**
705   * Ensures the truth of an expression involving the state of the calling instance, but not
706   * involving any parameters to the calling method.
707   *
708   * <p>See {@link #checkState(boolean, String, Object...)} for details.
709   *
710   * @since 20.0 (varargs overload since 2.0)
711   */
712  public static void checkState(
713      boolean expression, String errorMessageTemplate, int p1, @CheckForNull Object p2) {
714    if (!expression) {
715      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1, p2));
716    }
717  }
718
719  /**
720   * Ensures the truth of an expression involving the state of the calling instance, but not
721   * involving any parameters to the calling method.
722   *
723   * <p>See {@link #checkState(boolean, String, Object...)} for details.
724   *
725   * @since 20.0 (varargs overload since 2.0)
726   */
727  public static void checkState(boolean expression, String errorMessageTemplate, long p1, char p2) {
728    if (!expression) {
729      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1, p2));
730    }
731  }
732
733  /**
734   * Ensures the truth of an expression involving the state of the calling instance, but not
735   * involving any parameters to the calling method.
736   *
737   * <p>See {@link #checkState(boolean, String, Object...)} for details.
738   *
739   * @since 20.0 (varargs overload since 2.0)
740   */
741  public static void checkState(boolean expression, String errorMessageTemplate, long p1, int p2) {
742    if (!expression) {
743      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1, p2));
744    }
745  }
746
747  /**
748   * Ensures the truth of an expression involving the state of the calling instance, but not
749   * involving any parameters to the calling method.
750   *
751   * <p>See {@link #checkState(boolean, String, Object...)} for details.
752   *
753   * @since 20.0 (varargs overload since 2.0)
754   */
755  public static void checkState(boolean expression, String errorMessageTemplate, long p1, long p2) {
756    if (!expression) {
757      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1, p2));
758    }
759  }
760
761  /**
762   * Ensures the truth of an expression involving the state of the calling instance, but not
763   * involving any parameters to the calling method.
764   *
765   * <p>See {@link #checkState(boolean, String, Object...)} for details.
766   *
767   * @since 20.0 (varargs overload since 2.0)
768   */
769  public static void checkState(
770      boolean expression, String errorMessageTemplate, long p1, @CheckForNull Object p2) {
771    if (!expression) {
772      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1, p2));
773    }
774  }
775
776  /**
777   * Ensures the truth of an expression involving the state of the calling instance, but not
778   * involving any parameters to the calling method.
779   *
780   * <p>See {@link #checkState(boolean, String, Object...)} for details.
781   *
782   * @since 20.0 (varargs overload since 2.0)
783   */
784  public static void checkState(
785      boolean expression, String errorMessageTemplate, @CheckForNull Object p1, char p2) {
786    if (!expression) {
787      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1, p2));
788    }
789  }
790
791  /**
792   * Ensures the truth of an expression involving the state of the calling instance, but not
793   * involving any parameters to the calling method.
794   *
795   * <p>See {@link #checkState(boolean, String, Object...)} for details.
796   *
797   * @since 20.0 (varargs overload since 2.0)
798   */
799  public static void checkState(
800      boolean expression, String errorMessageTemplate, @CheckForNull Object p1, int p2) {
801    if (!expression) {
802      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1, p2));
803    }
804  }
805
806  /**
807   * Ensures the truth of an expression involving the state of the calling instance, but not
808   * involving any parameters to the calling method.
809   *
810   * <p>See {@link #checkState(boolean, String, Object...)} for details.
811   *
812   * @since 20.0 (varargs overload since 2.0)
813   */
814  public static void checkState(
815      boolean expression, String errorMessageTemplate, @CheckForNull Object p1, long p2) {
816    if (!expression) {
817      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1, p2));
818    }
819  }
820
821  /**
822   * Ensures the truth of an expression involving the state of the calling instance, but not
823   * involving any parameters to the calling method.
824   *
825   * <p>See {@link #checkState(boolean, String, Object...)} for details.
826   *
827   * @since 20.0 (varargs overload since 2.0)
828   */
829  public static void checkState(
830      boolean expression,
831      String errorMessageTemplate,
832      @CheckForNull Object p1,
833      @CheckForNull Object p2) {
834    if (!expression) {
835      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1, p2));
836    }
837  }
838
839  /**
840   * Ensures the truth of an expression involving the state of the calling instance, but not
841   * involving any parameters to the calling method.
842   *
843   * <p>See {@link #checkState(boolean, String, Object...)} for details.
844   *
845   * @since 20.0 (varargs overload since 2.0)
846   */
847  public static void checkState(
848      boolean expression,
849      String errorMessageTemplate,
850      @CheckForNull Object p1,
851      @CheckForNull Object p2,
852      @CheckForNull Object p3) {
853    if (!expression) {
854      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1, p2, p3));
855    }
856  }
857
858  /**
859   * Ensures the truth of an expression involving the state of the calling instance, but not
860   * involving any parameters to the calling method.
861   *
862   * <p>See {@link #checkState(boolean, String, Object...)} for details.
863   *
864   * @since 20.0 (varargs overload since 2.0)
865   */
866  public static void checkState(
867      boolean expression,
868      String errorMessageTemplate,
869      @CheckForNull Object p1,
870      @CheckForNull Object p2,
871      @CheckForNull Object p3,
872      @CheckForNull Object p4) {
873    if (!expression) {
874      throw new IllegalStateException(lenientFormat(errorMessageTemplate, p1, p2, p3, p4));
875    }
876  }
877
878  /*
879   * Preconditions.checkNotNull is *intended* for performing eager null checks on parameters that a
880   * nullness checker can already "prove" are non-null. That means that the first parameter to
881   * checkNotNull *should* be annotated to require it to be non-null.
882   *
883   * However, for a variety of reasons, Google developers have written a ton of code over the past
884   * decade that assumes that they can use checkNotNull for non-precondition checks. I had hoped to
885   * take a principled stand on this, but the amount of such code is simply overwhelming. To avoid
886   * creating a lot of compile errors that users would not find to be informative, we're giving in
887   * and allowing callers to pass arguments that a nullness checker believes could be null.
888   *
889   * We still encourage people to use requireNonNull over checkNotNull for non-precondition checks.
890   */
891
892  /**
893   * Ensures that an object reference passed as a parameter to the calling method is not null.
894   *
895   * @param reference an object reference
896   * @return the non-null reference that was validated
897   * @throws NullPointerException if {@code reference} is null
898   * @see Verify#verifyNotNull Verify.verifyNotNull()
899   */
900  @CanIgnoreReturnValue
901  public static <T> T checkNotNull(@CheckForNull T reference) {
902    if (reference == null) {
903      throw new NullPointerException();
904    }
905    return reference;
906  }
907
908  /**
909   * Ensures that an object reference passed as a parameter to the calling method is not null.
910   *
911   * @param reference an object reference
912   * @param errorMessage the exception message to use if the check fails; will be converted to a
913   *     string using {@link String#valueOf(Object)}
914   * @return the non-null reference that was validated
915   * @throws NullPointerException if {@code reference} is null
916   * @see Verify#verifyNotNull Verify.verifyNotNull()
917   */
918  @CanIgnoreReturnValue
919  public static <T> T checkNotNull(@CheckForNull T reference, @CheckForNull Object errorMessage) {
920    if (reference == null) {
921      throw new NullPointerException(String.valueOf(errorMessage));
922    }
923    return reference;
924  }
925
926  /**
927   * Ensures that an object reference passed as a parameter to the calling method is not null.
928   *
929   * @param reference an object reference
930   * @param errorMessageTemplate a template for the exception message should the check fail. The
931   *     message is formed by replacing each {@code %s} placeholder in the template with an
932   *     argument. These are matched by position - the first {@code %s} gets {@code
933   *     errorMessageArgs[0]}, etc. Unmatched arguments will be appended to the formatted message in
934   *     square braces. Unmatched placeholders will be left as-is.
935   * @param errorMessageArgs the arguments to be substituted into the message template. Arguments
936   *     are converted to strings using {@link String#valueOf(Object)}.
937   * @return the non-null reference that was validated
938   * @throws NullPointerException if {@code reference} is null
939   * @see Verify#verifyNotNull Verify.verifyNotNull()
940   */
941  @CanIgnoreReturnValue
942  public static <T> T checkNotNull(
943      @CheckForNull T reference,
944      String errorMessageTemplate,
945      @CheckForNull @Nullable Object... errorMessageArgs) {
946    if (reference == null) {
947      throw new NullPointerException(lenientFormat(errorMessageTemplate, errorMessageArgs));
948    }
949    return reference;
950  }
951
952  /**
953   * Ensures that an object reference passed as a parameter to the calling method is not null.
954   *
955   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
956   *
957   * @since 20.0 (varargs overload since 2.0)
958   */
959  @CanIgnoreReturnValue
960  public static <T> T checkNotNull(
961      @CheckForNull T reference, String errorMessageTemplate, char p1) {
962    if (reference == null) {
963      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1));
964    }
965    return reference;
966  }
967
968  /**
969   * Ensures that an object reference passed as a parameter to the calling method is not null.
970   *
971   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
972   *
973   * @since 20.0 (varargs overload since 2.0)
974   */
975  @CanIgnoreReturnValue
976  public static <T> T checkNotNull(@CheckForNull T reference, String errorMessageTemplate, int p1) {
977    if (reference == null) {
978      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1));
979    }
980    return reference;
981  }
982
983  /**
984   * Ensures that an object reference passed as a parameter to the calling method is not null.
985   *
986   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
987   *
988   * @since 20.0 (varargs overload since 2.0)
989   */
990  @CanIgnoreReturnValue
991  public static <T> T checkNotNull(
992      @CheckForNull T reference, String errorMessageTemplate, long p1) {
993    if (reference == null) {
994      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1));
995    }
996    return reference;
997  }
998
999  /**
1000   * Ensures that an object reference passed as a parameter to the calling method is not null.
1001   *
1002   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
1003   *
1004   * @since 20.0 (varargs overload since 2.0)
1005   */
1006  @CanIgnoreReturnValue
1007  public static <T> T checkNotNull(
1008      @CheckForNull T reference, String errorMessageTemplate, @CheckForNull Object p1) {
1009    if (reference == null) {
1010      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1));
1011    }
1012    return reference;
1013  }
1014
1015  /**
1016   * Ensures that an object reference passed as a parameter to the calling method is not null.
1017   *
1018   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
1019   *
1020   * @since 20.0 (varargs overload since 2.0)
1021   */
1022  @CanIgnoreReturnValue
1023  public static <T> T checkNotNull(
1024      @CheckForNull T reference, String errorMessageTemplate, char p1, char p2) {
1025    if (reference == null) {
1026      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
1027    }
1028    return reference;
1029  }
1030
1031  /**
1032   * Ensures that an object reference passed as a parameter to the calling method is not null.
1033   *
1034   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
1035   *
1036   * @since 20.0 (varargs overload since 2.0)
1037   */
1038  @CanIgnoreReturnValue
1039  public static <T> T checkNotNull(
1040      @CheckForNull T reference, String errorMessageTemplate, char p1, int p2) {
1041    if (reference == null) {
1042      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
1043    }
1044    return reference;
1045  }
1046
1047  /**
1048   * Ensures that an object reference passed as a parameter to the calling method is not null.
1049   *
1050   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
1051   *
1052   * @since 20.0 (varargs overload since 2.0)
1053   */
1054  @CanIgnoreReturnValue
1055  public static <T> T checkNotNull(
1056      @CheckForNull T reference, String errorMessageTemplate, char p1, long p2) {
1057    if (reference == null) {
1058      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
1059    }
1060    return reference;
1061  }
1062
1063  /**
1064   * Ensures that an object reference passed as a parameter to the calling method is not null.
1065   *
1066   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
1067   *
1068   * @since 20.0 (varargs overload since 2.0)
1069   */
1070  @CanIgnoreReturnValue
1071  public static <T> T checkNotNull(
1072      @CheckForNull T reference, String errorMessageTemplate, char p1, @CheckForNull Object p2) {
1073    if (reference == null) {
1074      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
1075    }
1076    return reference;
1077  }
1078
1079  /**
1080   * Ensures that an object reference passed as a parameter to the calling method is not null.
1081   *
1082   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
1083   *
1084   * @since 20.0 (varargs overload since 2.0)
1085   */
1086  @CanIgnoreReturnValue
1087  public static <T> T checkNotNull(
1088      @CheckForNull T reference, String errorMessageTemplate, int p1, char p2) {
1089    if (reference == null) {
1090      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
1091    }
1092    return reference;
1093  }
1094
1095  /**
1096   * Ensures that an object reference passed as a parameter to the calling method is not null.
1097   *
1098   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
1099   *
1100   * @since 20.0 (varargs overload since 2.0)
1101   */
1102  @CanIgnoreReturnValue
1103  public static <T> T checkNotNull(
1104      @CheckForNull T reference, String errorMessageTemplate, int p1, int p2) {
1105    if (reference == null) {
1106      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
1107    }
1108    return reference;
1109  }
1110
1111  /**
1112   * Ensures that an object reference passed as a parameter to the calling method is not null.
1113   *
1114   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
1115   *
1116   * @since 20.0 (varargs overload since 2.0)
1117   */
1118  @CanIgnoreReturnValue
1119  public static <T> T checkNotNull(
1120      @CheckForNull T reference, String errorMessageTemplate, int p1, long p2) {
1121    if (reference == null) {
1122      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
1123    }
1124    return reference;
1125  }
1126
1127  /**
1128   * Ensures that an object reference passed as a parameter to the calling method is not null.
1129   *
1130   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
1131   *
1132   * @since 20.0 (varargs overload since 2.0)
1133   */
1134  @CanIgnoreReturnValue
1135  public static <T> T checkNotNull(
1136      @CheckForNull T reference, String errorMessageTemplate, int p1, @CheckForNull Object p2) {
1137    if (reference == null) {
1138      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
1139    }
1140    return reference;
1141  }
1142
1143  /**
1144   * Ensures that an object reference passed as a parameter to the calling method is not null.
1145   *
1146   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
1147   *
1148   * @since 20.0 (varargs overload since 2.0)
1149   */
1150  @CanIgnoreReturnValue
1151  public static <T> T checkNotNull(
1152      @CheckForNull T reference, String errorMessageTemplate, long p1, char p2) {
1153    if (reference == null) {
1154      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
1155    }
1156    return reference;
1157  }
1158
1159  /**
1160   * Ensures that an object reference passed as a parameter to the calling method is not null.
1161   *
1162   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
1163   *
1164   * @since 20.0 (varargs overload since 2.0)
1165   */
1166  @CanIgnoreReturnValue
1167  public static <T> T checkNotNull(
1168      @CheckForNull T reference, String errorMessageTemplate, long p1, int p2) {
1169    if (reference == null) {
1170      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
1171    }
1172    return reference;
1173  }
1174
1175  /**
1176   * Ensures that an object reference passed as a parameter to the calling method is not null.
1177   *
1178   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
1179   *
1180   * @since 20.0 (varargs overload since 2.0)
1181   */
1182  @CanIgnoreReturnValue
1183  public static <T> T checkNotNull(
1184      @CheckForNull T reference, String errorMessageTemplate, long p1, long p2) {
1185    if (reference == null) {
1186      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
1187    }
1188    return reference;
1189  }
1190
1191  /**
1192   * Ensures that an object reference passed as a parameter to the calling method is not null.
1193   *
1194   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
1195   *
1196   * @since 20.0 (varargs overload since 2.0)
1197   */
1198  @CanIgnoreReturnValue
1199  public static <T> T checkNotNull(
1200      @CheckForNull T reference, String errorMessageTemplate, long p1, @CheckForNull Object p2) {
1201    if (reference == null) {
1202      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
1203    }
1204    return reference;
1205  }
1206
1207  /**
1208   * Ensures that an object reference passed as a parameter to the calling method is not null.
1209   *
1210   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
1211   *
1212   * @since 20.0 (varargs overload since 2.0)
1213   */
1214  @CanIgnoreReturnValue
1215  public static <T> T checkNotNull(
1216      @CheckForNull T reference, String errorMessageTemplate, @CheckForNull Object p1, char p2) {
1217    if (reference == null) {
1218      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
1219    }
1220    return reference;
1221  }
1222
1223  /**
1224   * Ensures that an object reference passed as a parameter to the calling method is not null.
1225   *
1226   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
1227   *
1228   * @since 20.0 (varargs overload since 2.0)
1229   */
1230  @CanIgnoreReturnValue
1231  public static <T> T checkNotNull(
1232      @CheckForNull T reference, String errorMessageTemplate, @CheckForNull Object p1, int p2) {
1233    if (reference == null) {
1234      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
1235    }
1236    return reference;
1237  }
1238
1239  /**
1240   * Ensures that an object reference passed as a parameter to the calling method is not null.
1241   *
1242   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
1243   *
1244   * @since 20.0 (varargs overload since 2.0)
1245   */
1246  @CanIgnoreReturnValue
1247  public static <T> T checkNotNull(
1248      @CheckForNull T reference, String errorMessageTemplate, @CheckForNull Object p1, long p2) {
1249    if (reference == null) {
1250      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
1251    }
1252    return reference;
1253  }
1254
1255  /**
1256   * Ensures that an object reference passed as a parameter to the calling method is not null.
1257   *
1258   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
1259   *
1260   * @since 20.0 (varargs overload since 2.0)
1261   */
1262  @CanIgnoreReturnValue
1263  public static <T> T checkNotNull(
1264      @CheckForNull T reference,
1265      String errorMessageTemplate,
1266      @CheckForNull Object p1,
1267      @CheckForNull Object p2) {
1268    if (reference == null) {
1269      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
1270    }
1271    return reference;
1272  }
1273
1274  /**
1275   * Ensures that an object reference passed as a parameter to the calling method is not null.
1276   *
1277   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
1278   *
1279   * @since 20.0 (varargs overload since 2.0)
1280   */
1281  @CanIgnoreReturnValue
1282  public static <T> T checkNotNull(
1283      @CheckForNull T reference,
1284      String errorMessageTemplate,
1285      @CheckForNull Object p1,
1286      @CheckForNull Object p2,
1287      @CheckForNull Object p3) {
1288    if (reference == null) {
1289      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2, p3));
1290    }
1291    return reference;
1292  }
1293
1294  /**
1295   * Ensures that an object reference passed as a parameter to the calling method is not null.
1296   *
1297   * <p>See {@link #checkNotNull(Object, String, Object...)} for details.
1298   *
1299   * @since 20.0 (varargs overload since 2.0)
1300   */
1301  @CanIgnoreReturnValue
1302  public static <T> T checkNotNull(
1303      @CheckForNull T reference,
1304      String errorMessageTemplate,
1305      @CheckForNull Object p1,
1306      @CheckForNull Object p2,
1307      @CheckForNull Object p3,
1308      @CheckForNull Object p4) {
1309    if (reference == null) {
1310      throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2, p3, p4));
1311    }
1312    return reference;
1313  }
1314
1315  /*
1316   * All recent hotspots (as of 2009) *really* like to have the natural code
1317   *
1318   * if (guardExpression) {
1319   *    throw new BadException(messageExpression);
1320   * }
1321   *
1322   * refactored so that messageExpression is moved to a separate String-returning method.
1323   *
1324   * if (guardExpression) {
1325   *    throw new BadException(badMsg(...));
1326   * }
1327   *
1328   * The alternative natural refactorings into void or Exception-returning methods are much slower.
1329   * This is a big deal - we're talking factors of 2-8 in microbenchmarks, not just 10-20%. (This is
1330   * a hotspot optimizer bug, which should be fixed, but that's a separate, big project).
1331   *
1332   * The coding pattern above is heavily used in java.util, e.g. in ArrayList. There is a
1333   * RangeCheckMicroBenchmark in the JDK that was used to test this.
1334   *
1335   * But the methods in this class want to throw different exceptions, depending on the args, so it
1336   * appears that this pattern is not directly applicable. But we can use the ridiculous, devious
1337   * trick of throwing an exception in the middle of the construction of another exception. Hotspot
1338   * is fine with that.
1339   */
1340
1341  /**
1342   * Ensures that {@code index} specifies a valid <i>element</i> in an array, list or string of size
1343   * {@code size}. An element index may range from zero, inclusive, to {@code size}, exclusive.
1344   *
1345   * @param index a user-supplied index identifying an element of an array, list or string
1346   * @param size the size of that array, list or string
1347   * @return the value of {@code index}
1348   * @throws IndexOutOfBoundsException if {@code index} is negative or is not less than {@code size}
1349   * @throws IllegalArgumentException if {@code size} is negative
1350   */
1351  @CanIgnoreReturnValue
1352  public static int checkElementIndex(int index, int size) {
1353    return checkElementIndex(index, size, "index");
1354  }
1355
1356  /**
1357   * Ensures that {@code index} specifies a valid <i>element</i> in an array, list or string of size
1358   * {@code size}. An element index may range from zero, inclusive, to {@code size}, exclusive.
1359   *
1360   * @param index a user-supplied index identifying an element of an array, list or string
1361   * @param size the size of that array, list or string
1362   * @param desc the text to use to describe this index in an error message
1363   * @return the value of {@code index}
1364   * @throws IndexOutOfBoundsException if {@code index} is negative or is not less than {@code size}
1365   * @throws IllegalArgumentException if {@code size} is negative
1366   */
1367  @CanIgnoreReturnValue
1368  public static int checkElementIndex(int index, int size, String desc) {
1369    // Carefully optimized for execution by hotspot (explanatory comment above)
1370    if (index < 0 || index >= size) {
1371      throw new IndexOutOfBoundsException(badElementIndex(index, size, desc));
1372    }
1373    return index;
1374  }
1375
1376  private static String badElementIndex(int index, int size, String desc) {
1377    if (index < 0) {
1378      return lenientFormat("%s (%s) must not be negative", desc, index);
1379    } else if (size < 0) {
1380      throw new IllegalArgumentException("negative size: " + size);
1381    } else { // index >= size
1382      return lenientFormat("%s (%s) must be less than size (%s)", desc, index, size);
1383    }
1384  }
1385
1386  /**
1387   * Ensures that {@code index} specifies a valid <i>position</i> in an array, list or string of
1388   * size {@code size}. A position index may range from zero to {@code size}, inclusive.
1389   *
1390   * @param index a user-supplied index identifying a position in an array, list or string
1391   * @param size the size of that array, list or string
1392   * @return the value of {@code index}
1393   * @throws IndexOutOfBoundsException if {@code index} is negative or is greater than {@code size}
1394   * @throws IllegalArgumentException if {@code size} is negative
1395   */
1396  @CanIgnoreReturnValue
1397  public static int checkPositionIndex(int index, int size) {
1398    return checkPositionIndex(index, size, "index");
1399  }
1400
1401  /**
1402   * Ensures that {@code index} specifies a valid <i>position</i> in an array, list or string of
1403   * size {@code size}. A position index may range from zero to {@code size}, inclusive.
1404   *
1405   * @param index a user-supplied index identifying a position in an array, list or string
1406   * @param size the size of that array, list or string
1407   * @param desc the text to use to describe this index in an error message
1408   * @return the value of {@code index}
1409   * @throws IndexOutOfBoundsException if {@code index} is negative or is greater than {@code size}
1410   * @throws IllegalArgumentException if {@code size} is negative
1411   */
1412  @CanIgnoreReturnValue
1413  public static int checkPositionIndex(int index, int size, String desc) {
1414    // Carefully optimized for execution by hotspot (explanatory comment above)
1415    if (index < 0 || index > size) {
1416      throw new IndexOutOfBoundsException(badPositionIndex(index, size, desc));
1417    }
1418    return index;
1419  }
1420
1421  private static String badPositionIndex(int index, int size, String desc) {
1422    if (index < 0) {
1423      return lenientFormat("%s (%s) must not be negative", desc, index);
1424    } else if (size < 0) {
1425      throw new IllegalArgumentException("negative size: " + size);
1426    } else { // index > size
1427      return lenientFormat("%s (%s) must not be greater than size (%s)", desc, index, size);
1428    }
1429  }
1430
1431  /**
1432   * Ensures that {@code start} and {@code end} specify valid <i>positions</i> in an array, list or
1433   * string of size {@code size}, and are in order. A position index may range from zero to {@code
1434   * size}, inclusive.
1435   *
1436   * @param start a user-supplied index identifying a starting position in an array, list or string
1437   * @param end a user-supplied index identifying an ending position in an array, list or string
1438   * @param size the size of that array, list or string
1439   * @throws IndexOutOfBoundsException if either index is negative or is greater than {@code size},
1440   *     or if {@code end} is less than {@code start}
1441   * @throws IllegalArgumentException if {@code size} is negative
1442   */
1443  public static void checkPositionIndexes(int start, int end, int size) {
1444    // Carefully optimized for execution by hotspot (explanatory comment above)
1445    if (start < 0 || end < start || end > size) {
1446      throw new IndexOutOfBoundsException(badPositionIndexes(start, end, size));
1447    }
1448  }
1449
1450  private static String badPositionIndexes(int start, int end, int size) {
1451    if (start < 0 || start > size) {
1452      return badPositionIndex(start, size, "start index");
1453    }
1454    if (end < 0 || end > size) {
1455      return badPositionIndex(end, size, "end index");
1456    }
1457    // end < start
1458    return lenientFormat("end index (%s) must not be less than start index (%s)", end, start);
1459  }
1460}