Use Objects.requireNonNull()

See #71

src-extra/main/java/javax/time/extra/DayOfYear.java

@@ -35,6 +35,7 @@
 import static javax.time.calendrical.LocalDateTimeField.YEAR;
 
 import java.io.Serializable;
+import java.util.Objects;
 import java.util.concurrent.atomic.AtomicReferenceArray;
 
 import javax.time.DateTimeException;
@@ -180,9 +181,7 @@ public DateTime doAdjustment(DateTime calendrical) {
      * @return true if this day-of-year is valid for the year
      */
     public boolean isValid(Year year) {
-        if (year == null) {
-            throw new NullPointerException("Year must not be null");
-        }
+        Objects.requireNonNull(year, "Year");
         return (dayOfYear < 366 || year.isLeap());
     }
 
@@ -213,7 +212,7 @@ public boolean isValid(int year) {
      */
     public LocalDate atYear(Year year) {
         if (year == null) {
-            throw new NullPointerException("Year must not be null");
+            throw new NullPointerException("Year");
         }
         return year.atDay(dayOfYear);
     }

src-extra/main/java/javax/time/extra/QuarterOfYear.java

@@ -34,9 +34,9 @@
 import static javax.time.extra.QuarterYearField.QUARTER_OF_YEAR;
 
 import java.util.Locale;
+import java.util.Objects;
 
 import javax.time.DateTimeException;
-import javax.time.DateTimes;
 import javax.time.Month;
 import javax.time.calendrical.DateTime;
 import javax.time.calendrical.DateTime.WithAdjuster;
@@ -129,7 +129,7 @@ public static QuarterOfYear of(int quarterOfYear) {
      * @return the QuarterOfYear singleton, not null
      */
     public static QuarterOfYear ofMonth(Month month) {
-        DateTimes.checkNotNull(month, "Month must not be null");
+        Objects.requireNonNull(month, "Month");
         return of(month.ordinal() / 3 + 1);
     }
 

src-extra/main/java/javax/time/extra/TAIInstant.java

@@ -32,13 +32,14 @@
 package javax.time.extra;
 
 import java.io.Serializable;
+import java.util.Objects;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 import javax.time.DateTimeException;
+import javax.time.DateTimes;
 import javax.time.Duration;
 import javax.time.Instant;
-import javax.time.DateTimes;
 import javax.time.format.DateTimeParseException;
 
 /**
@@ -190,7 +191,7 @@ public static TAIInstant of(UTCInstant instant) {
      * @throws DateTimeException if the text cannot be parsed
      */
     public static TAIInstant parse(CharSequence text) {
-        DateTimes.checkNotNull(text, "Text to parse must not be null");
+        Objects.requireNonNull(text, "Text ");
         Matcher matcher = PARSER.matcher(text);
         if (matcher.matches()) {
             try {

src-standard/main/java/javax/time/chrono/Chronology.java

@@ -33,13 +33,13 @@
 
 import java.util.HashSet;
 import java.util.Locale;
+import java.util.Objects;
 import java.util.ServiceLoader;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 
 import javax.time.Clock;
 import javax.time.DateTimeException;
-import javax.time.DateTimes;
 import javax.time.LocalDate;
 import javax.time.ZoneId;
 import javax.time.calendrical.DateTimeAccessor;
@@ -140,7 +140,7 @@ public static Chronology from(DateTimeAccessor dateTime) {
      * @throws DateTimeException if the locale-specified calendar cannot be found
      */
     public static Chronology ofLocale(Locale locale) {
-        DateTimes.checkNotNull(locale, "Locale must not be null");
+        Objects.requireNonNull(locale, "Locale");
         String type = locale.getUnicodeLocaleType("ca");
         if (type == null) {
             return ISOChronology.INSTANCE;
@@ -345,7 +345,6 @@ public ChronoDate now(ZoneId zone) {
      * @return the current date, not null
      */
     public ChronoDate now(Clock clock) {
-        DateTimes.checkNotNull(clock, "Clock must not be null");
         return dateFromEpochDay(LocalDate.now(clock).toEpochDay());
     }
 

src-standard/main/java/javax/time/chrono/HijrahDate.java

@@ -45,6 +45,7 @@
 import java.io.Serializable;
 import java.text.ParseException;
 import java.util.HashMap;
+import java.util.Objects;
 import java.util.StringTokenizer;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipFile;
@@ -433,7 +434,7 @@ public static HijrahDate of(int prolepticYear, int monthOfYear, int dayOfMonth)
      * @throws InvalidCalendarFieldException if the day-of-month is invalid for the month-year
      */
     public static HijrahDate of(HijrahEra era, int yearOfEra, int monthOfYear, int dayOfMonth) {
-        DateTimes.checkNotNull(era, "HijrahEra must not be null");
+        Objects.requireNonNull(era, "HijrahEra");
         checkValidYearOfEra(yearOfEra);
         checkValidMonth(monthOfYear);
         checkValidDayOfMonth(dayOfMonth);

src-standard/main/java/javax/time/chrono/ISODate.java

@@ -32,8 +32,8 @@
 package javax.time.chrono;
 
 import java.io.Serializable;
+import java.util.Objects;
 
-import javax.time.DateTimes;
 import javax.time.LocalDate;
 import javax.time.calendrical.DateTimeField;
 import javax.time.calendrical.DateTimeValueRange;
@@ -67,7 +67,7 @@ final class ISODate extends ChronoDate implements Comparable<ChronoDate>, Serial
      * @param date  the time-line date, not null
      */
     ISODate(LocalDate date) {
-        DateTimes.checkNotNull(date, "LocalDate must not be null");
+        Objects.requireNonNull(date, "LocalDate");
         this.isoDate = date;
     }
 

src-standard/main/java/javax/time/chrono/JapaneseDate.java

@@ -35,9 +35,9 @@
 import java.io.ObjectInputStream;
 import java.io.Serializable;
 import java.util.Calendar;
+import java.util.Objects;
 
 import javax.time.DateTimeException;
-import javax.time.DateTimes;
 import javax.time.LocalDate;
 import javax.time.calendrical.DateTimeField;
 import javax.time.calendrical.DateTimeValueRange;
@@ -106,7 +106,7 @@ public static JapaneseDate of(int prolepticYear, int month, int dayOfMonth) {
      *                           if the day-of-month is invalid for the month-year
      */
     static JapaneseDate of(JapaneseEra era, int yearOfEra, int month, int dayOfMonth) {
-        DateTimes.checkNotNull(era, "era must not be null");
+        Objects.requireNonNull(era, "Era");
         LocalGregorianCalendar.Date jdate = JapaneseChronology.JCAL.newCalendarDate(null);
         jdate.setEra(era.getPrivateEra()).setDate(yearOfEra, month, dayOfMonth);
         if (!JapaneseChronology.JCAL.validate(jdate)) {

src-standard/main/java/javax/time/chrono/MinguoDate.java

@@ -35,8 +35,8 @@
 import static javax.time.chrono.MinguoChronology.YEARS_DIFFERENCE;
 
 import java.io.Serializable;
+import java.util.Objects;
 
-import javax.time.DateTimes;
 import javax.time.LocalDate;
 import javax.time.calendrical.DateTimeField;
 import javax.time.calendrical.DateTimeValueRange;
@@ -71,7 +71,7 @@ final class MinguoDate extends ChronoDate implements Comparable<ChronoDate>, Ser
      * @param date  the time-line date, not null
      */
     MinguoDate(LocalDate date) {
-        DateTimes.checkNotNull(date, "LocalDate must not be null");
+        Objects.requireNonNull(date, "LocalDate");
         this.isoDate = date;
     }
 

src-standard/main/java/javax/time/chrono/ThaiBuddhistDate.java

@@ -35,9 +35,9 @@
 import static javax.time.chrono.ThaiBuddhistChronology.YEARS_DIFFERENCE;
 
 import java.io.Serializable;
+import java.util.Objects;
 
 import javax.time.DateTimeException;
-import javax.time.DateTimes;
 import javax.time.LocalDate;
 import javax.time.calendrical.DateTimeAccessor;
 import javax.time.calendrical.DateTimeField;
@@ -105,7 +105,7 @@ public static ChronoDate ofEpochDay(long epochDay) {
      * @param date  the time-line date, not null
      */
     ThaiBuddhistDate(LocalDate date) {
-        DateTimes.checkNotNull(date, "LocalDate must not be null");
+        Objects.requireNonNull(date, "LocalDate");
         this.isoDate = date;
     }
 

src/main/java/javax/time/Clock.java

@@ -35,6 +35,7 @@
 import static javax.time.DateTimes.NANOS_PER_SECOND;
 
 import java.io.Serializable;
+import java.util.Objects;
 import java.util.TimeZone;
 
 /**
@@ -123,7 +124,7 @@ public static Clock systemUTC() {
      * @return a clock that uses the best available system clock in the specified zone, not null
      */
     public static Clock system(ZoneId zone) {
-        DateTimes.checkNotNull(zone, "ZoneId must not be null");
+        Objects.requireNonNull(zone, "ZoneId");
         return new SystemClock(zone);
     }
 
@@ -203,8 +204,8 @@ public static Clock tickMinutes(ZoneId zone) {
      * @throws ArithmeticException if the duration is too large
      */
     public static Clock tick(Clock baseClock, Duration tickDuration) {
-        DateTimes.checkNotNull(baseClock, "Clock must not be null");
-        DateTimes.checkNotNull(tickDuration, "Duration must not be null");
+        Objects.requireNonNull(baseClock, "Clock");
+        Objects.requireNonNull(tickDuration, "Duration");
         if (tickDuration.isNegative()) {
             throw new IllegalArgumentException("Duration must not be negative");
         }
@@ -230,7 +231,7 @@ public static Clock tick(Clock baseClock, Duration tickDuration) {
      * @return a clock that always returns the same instant, not null
      */
     public static Clock fixedUTC(Instant fixedInstant) {
-        DateTimes.checkNotNull(fixedInstant, "Instant must not be null");
+        Objects.requireNonNull(fixedInstant, "Instant");
         return new FixedClock(fixedInstant, ZoneId.UTC);
     }
 
@@ -249,8 +250,8 @@ public static Clock fixedUTC(Instant fixedInstant) {
      * @return a clock that always returns the same instant, not null
      */
     public static Clock fixed(Instant fixedInstant, ZoneId zone) {
-        DateTimes.checkNotNull(fixedInstant, "Instant must not be null");
-        DateTimes.checkNotNull(zone, "ZoneId must not be null");
+        Objects.requireNonNull(fixedInstant, "Instant");
+        Objects.requireNonNull(zone, "ZoneId");
         return new FixedClock(fixedInstant, zone);
     }
 
@@ -269,8 +270,8 @@ public static Clock fixed(Instant fixedInstant, ZoneId zone) {
      * @return a {@code TimeSource} that is offset from the system millisecond clock, not null
      */
     public static Clock offset(Clock baseClock, Duration offset) {
-        DateTimes.checkNotNull(baseClock, "Clock must not be null");
-        DateTimes.checkNotNull(offset, "Duration must not be null");
+        Objects.requireNonNull(baseClock, "Clock");
+        Objects.requireNonNull(offset, "Duration");
         if (offset.equals(Duration.ZERO)) {
             return baseClock;
         }

src/main/java/javax/time/DateTimes.java

@@ -108,19 +108,6 @@ private DateTimes() {
     }
 
     //-----------------------------------------------------------------------
-    /**
-     * Validates that the specified object is not null.
-     *
-     * @param object  the object to check
-     * @param errorMessage  the error message to use if null
-     * @throws NullPointerException if the object is null
-     */
-    public static void checkNotNull(Object object, String errorMessage) {
-        if (object == null) {
-            throw new NullPointerException(errorMessage);
-        }
-    }
-
     /**
      * Validates that the specified object is not null.
      *

src/main/java/javax/time/Duration.java

@@ -39,6 +39,7 @@
 import java.math.BigDecimal;
 import java.math.BigInteger;
 import java.math.RoundingMode;
+import java.util.Objects;
 
 import javax.time.calendrical.DateTime;
 import javax.time.calendrical.DateTime.MinusAdjuster;
@@ -288,7 +289,7 @@ public static Duration between(DateTimeAccessor startInclusive, DateTimeAccessor
      * @throws DateTimeParseException if the text cannot be parsed to a {@code Duration}
      */
     public static Duration parse(final CharSequence text) {
-        DateTimes.checkNotNull(text, "Text to parse must not be null");
+        Objects.requireNonNull(text, "Text to parse");
         int len = text.length();
         if (len < 4 ||
                 (text.charAt(0) != 'P' && text.charAt(0) != 'p') ||
@@ -497,6 +498,7 @@ public Duration plus(Duration duration) {
      * @throws ArithmeticException if numeric overflow occurs
      */
     public Duration plus(long amountToAdd, PeriodUnit unit) {
+        Objects.requireNonNull(unit, "PeriodUnit");
         if (unit == DAYS) {
             return plus(DateTimes.safeMultiply(amountToAdd, DateTimes.SECONDS_PER_DAY), 0);
         }

src/main/java/javax/time/Instant.java

@@ -38,6 +38,7 @@
 import static javax.time.calendrical.LocalDateTimeField.NANO_OF_SECOND;
 
 import java.io.Serializable;
+import java.util.Objects;
 
 import javax.time.calendrical.DateTime;
 import javax.time.calendrical.DateTime.WithAdjuster;
@@ -193,7 +194,7 @@ public static Instant now() {
      * @return the current instant, not null
      */
     public static Instant now(Clock clock) {
-        DateTimes.checkNotNull(clock, "Clock must not be null");
+        Objects.requireNonNull(clock, "Clock");
         return clock.instant();
     }
 

src/main/java/javax/time/LocalDate.java

@@ -44,6 +44,7 @@
 import static javax.time.calendrical.LocalDateTimeField.YEAR;
 
 import java.io.Serializable;
+import java.util.Objects;
 
 import javax.time.calendrical.DateTime;
 import javax.time.calendrical.DateTime.WithAdjuster;
@@ -167,7 +168,7 @@ public static LocalDate now(ZoneId zone) {
      * @return the current date, not null
      */
     public static LocalDate now(Clock clock) {
-        DateTimes.checkNotNull(clock, "Clock must not be null");
+        Objects.requireNonNull(clock, "Clock");
         // inline OffsetDate factory to avoid creating object and InstantProvider checks
         final Instant now = clock.instant();  // called once
         ZoneOffset offset = clock.getZone().getRules().getOffset(now);
@@ -191,7 +192,7 @@ public static LocalDate now(Clock clock) {
      */
     public static LocalDate of(int year, Month month, int dayOfMonth) {
         YEAR.checkValidValue(year);
-        DateTimes.checkNotNull(month, "Month must not be null");
+        Objects.requireNonNull(month, "Month");
         DAY_OF_MONTH.checkValidValue(dayOfMonth);
         return create(year, month, dayOfMonth);
     }
@@ -328,7 +329,7 @@ public static LocalDate parse(CharSequence text) {
      * @throws DateTimeParseException if the text cannot be parsed
      */
     public static LocalDate parse(CharSequence text, CalendricalFormatter formatter) {
-        DateTimes.checkNotNull(formatter, "CalendricalFormatter must not be null");
+        Objects.requireNonNull(formatter, "CalendricalFormatter");
         return formatter.parse(text, LocalDate.class);
     }
 
@@ -1380,7 +1381,7 @@ public String toString() {
      * @throws DateTimeException if an error occurs during printing
      */
     public String toString(CalendricalFormatter formatter) {
-        DateTimes.checkNotNull(formatter, "CalendricalFormatter must not be null");
+        Objects.requireNonNull(formatter, "CalendricalFormatter");
         return formatter.print(this);
     }