APPLIED: Static methods on chrono classes. Patch for ThreeTen/threeten#203

ThreeTen203

diff --git a/src/share/classes/java/time/chrono/ChronoLocalDate.java b/src/share/classes/java/time/chrono/ChronoLocalDate.java
--- a/src/share/classes/java/time/chrono/ChronoLocalDate.java
+++ b/src/share/classes/java/time/chrono/ChronoLocalDate.java
@@ -270,6 +270,39 @@
 
     //-----------------------------------------------------------------------
     /**
+     * Obtains an instance of {@code ChronoLocalDate} from a temporal object.
+     * <p>
+     * This creates a local date based on the specified temporal.
+     * A {@code TemporalAccessor} represents some form of date and time information.
+     * This factory converts the arbitrary temporal object to an instance of {@code ChronoLocalDate}.
+     * <p>
+     * The conversion extracts and combines the chronology and date.
+     * The chronology is extracted first, delegating the rest of the conversion
+     * to {@link Chronology#date(TemporalAccessor)}
+     * Implementations are permitted to perform optimizations such as accessing
+     * those fields that are equivalent to the relevant objects.
+     * <p>
+     * This method matches the signature of the functional interface {@link TemporalQuery}
+     * allowing it to be used as a query via method reference, {@code ChronoLocalDate::from}.
+     *
+     * @param temporal  the temporal object to convert, not null
+     * @return the date, not null
+     * @throws DateTimeException if unable to convert to a {@code ChronoLocalDate}
+     * @see Chronology#date(TemporalAccessor)
+     */
+    public static ChronoLocalDate<?> from(TemporalAccessor temporal) {
+        if (temporal instanceof ChronoLocalDate) {
+            return (ChronoLocalDate) temporal;
+        }
+        Chronology<?> chrono = temporal.query(Queries.chronology());
+        if (chrono == null) {
+            throw new DateTimeException("Unable to obtain ChronoLocalDate from TemporalAccessor: " + temporal.getClass());
+        }
+        return chrono.date(temporal);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
      * Gets the chronology of this date.
      * <p>
      * The {@code Chronology} represents the calendar system in use.
diff --git a/src/share/classes/java/time/chrono/ChronoLocalDateTime.java b/src/share/classes/java/time/chrono/ChronoLocalDateTime.java
--- a/src/share/classes/java/time/chrono/ChronoLocalDateTime.java
+++ b/src/share/classes/java/time/chrono/ChronoLocalDateTime.java
@@ -142,6 +142,40 @@
         }
     };
 
+    //-----------------------------------------------------------------------
+    /**
+     * Obtains an instance of {@code ChronoLocalDateTime} from a temporal object.
+     * <p>
+     * This creates a local date-time based on the specified temporal.
+     * A {@code TemporalAccessor} represents some form of date and time information.
+     * This factory converts the arbitrary temporal object to an instance of {@code ChronoLocalDateTime}.
+     * <p>
+     * The conversion extracts and combines the chronology, date and time.
+     * The chronology is extracted first, delegating the rest of the conversion
+     * to {@link Chronology#localDateTime(TemporalAccessor)}
+     * Implementations are permitted to perform optimizations such as accessing
+     * those fields that are equivalent to the relevant objects.
+     * <p>
+     * This method matches the signature of the functional interface {@link TemporalQuery}
+     * allowing it to be used as a query via method reference, {@code ChronoLocalDateTime::from}.
+     *
+     * @param temporal  the temporal object to convert, not null
+     * @return the date-time, not null
+     * @throws DateTimeException if unable to convert to a {@code ChronoLocalDateTime}
+     * @see Chronology#localDateTime(TemporalAccessor)
+     */
+    public static ChronoLocalDateTime<?> from(TemporalAccessor temporal) {
+        if (temporal instanceof ChronoLocalDateTime) {
+            return (ChronoLocalDateTime) temporal;
+        }
+        Chronology<?> chrono = temporal.query(Queries.chronology());
+        if (chrono == null) {
+            throw new DateTimeException("Unable to obtain ChronoLocalDateTime from TemporalAccessor: " + temporal.getClass());
+        }
+        return chrono.localDateTime(temporal);
+    }
+
+    //-----------------------------------------------------------------------
     /**
      * Gets the local date part of this date-time.
      * <p>
diff --git a/src/share/classes/java/time/chrono/ChronoZonedDateTime.java b/src/share/classes/java/time/chrono/ChronoZonedDateTime.java
--- a/src/share/classes/java/time/chrono/ChronoZonedDateTime.java
+++ b/src/share/classes/java/time/chrono/ChronoZonedDateTime.java
@@ -141,6 +141,40 @@
         }
     };
 
+    //-----------------------------------------------------------------------
+    /**
+     * Obtains an instance of {@code ChronoZonedDateTime} from a temporal object.
+     * <p>
+     * This creates a zoned date-time based on the specified temporal.
+     * A {@code TemporalAccessor} represents some form of date and time information.
+     * This factory converts the arbitrary temporal object to an instance of {@code ChronoZonedDateTime}.
+     * <p>
+     * The conversion extracts and combines the chronology, date, time and zone.
+     * The chronology is extracted first, delegating the rest of the conversion
+     * to {@link Chronology#zonedDateTime(TemporalAccessor)}
+     * Implementations are permitted to perform optimizations such as accessing
+     * those fields that are equivalent to the relevant objects.
+     * <p>
+     * This method matches the signature of the functional interface {@link TemporalQuery}
+     * allowing it to be used as a query via method reference, {@code ChronoZonedDateTime::from}.
+     *
+     * @param temporal  the temporal object to convert, not null
+     * @return the date-time, not null
+     * @throws DateTimeException if unable to convert to a {@code ChronoZonedDateTime}
+     * @see Chronology#zonedDateTime(TemporalAccessor)
+     */
+    public static ChronoZonedDateTime<?> from(TemporalAccessor temporal) {
+        if (temporal instanceof ChronoZonedDateTime) {
+            return (ChronoZonedDateTime) temporal;
+        }
+        Chronology<?> chrono = temporal.query(Queries.chronology());
+        if (chrono == null) {
+            throw new DateTimeException("Unable to obtain ChronoZonedDateTime from TemporalAccessor: " + temporal.getClass());
+        }
+        return chrono.zonedDateTime(temporal);
+    }
+
+    //-----------------------------------------------------------------------
     @Override
     public default ValueRange range(TemporalField field) {
         if (field instanceof ChronoField) {
diff --git a/src/share/classes/java/time/chrono/Chronology.java b/src/share/classes/java/time/chrono/Chronology.java
--- a/src/share/classes/java/time/chrono/Chronology.java
+++ b/src/share/classes/java/time/chrono/Chronology.java
@@ -595,6 +595,7 @@
      * @param temporal  the temporal object to convert, not null
      * @return the local date in this chronology, not null
      * @throws DateTimeException if unable to create the date
+     * @see ChronoLocalDate#from(TemporalAccessor)
      */
     public abstract ChronoLocalDate<C> date(TemporalAccessor temporal);
 
@@ -617,6 +618,7 @@
      * @param temporal  the temporal object to convert, not null
      * @return the local date-time in this chronology, not null
      * @throws DateTimeException if unable to create the date-time
+     * @see ChronoLocalDateTime#from(TemporalAccessor)
      */
     public ChronoLocalDateTime<C> localDateTime(TemporalAccessor temporal) {
         try {
@@ -648,6 +650,7 @@
      * @param temporal  the temporal object to convert, not null
      * @return the zoned date-time in this chronology, not null
      * @throws DateTimeException if unable to create the date-time
+     * @see ChronoZonedDateTime#from(TemporalAccessor)
      */
     public ChronoZonedDateTime<C> zonedDateTime(TemporalAccessor temporal) {
         try {