Allow constructing a microsoft.sql.DateTimeOffset instance from a java.time.OffsetDateTime value

src/main/java/microsoft/sql/DateTimeOffset.java

@@ -72,6 +72,21 @@ private DateTimeOffset(java.sql.Timestamp timestamp, int minutesOffset) {
         assert 0 == this.utcMillis % 1000L : "utcMillis: " + this.utcMillis;
     }
 
+    /**
+     * Constructs a DateTimeOffset from an existing java.time.OffsetDateTime
+     *
+     * @param offsetDateTime A java.time.OffsetDateTime value
+     * @apiNote DateTimeOffset represents values to 100ns precision. If the java.time.OffsetDateTime instance represents
+     * a value that is more precise, values in excess of the 100ns precision are rounded to the nearest
+     * multiple of 100ns. Values within 50 nanoseconds of the next second are rounded up to the next second.
+     */
+    private DateTimeOffset(java.time.OffsetDateTime offsetDateTime) {
+        int hundredNanos = ((offsetDateTime.getNano() + 50) / 100);
+        this.utcMillis = (offsetDateTime.toEpochSecond() * 1000) + (hundredNanos / HUNDRED_NANOS_PER_SECOND * 1000);
+        this.nanos = 100 * (hundredNanos % HUNDRED_NANOS_PER_SECOND);
+        this.minutesOffset = offsetDateTime.getOffset().getTotalSeconds() / 60;
+    }
+
     /**
      * Converts a java.sql.Timestamp value with an integer offset to the equivalent DateTimeOffset value
      * 
@@ -105,6 +120,19 @@ public static DateTimeOffset valueOf(java.sql.Timestamp timestamp, Calendar cale
                 (calendar.get(Calendar.ZONE_OFFSET) + calendar.get(Calendar.DST_OFFSET)) / (60 * 1000));
     }
 
+    /**
+     * Directly converts a {@link java.time.OffsetDateTime} value to an equivalent {@link DateTimeOffset} value
+     *
+     * @param offsetDateTime A java.time.OffsetDateTime value
+     * @return The DateTimeOffset value of the input java.time.OffsetDateTime
+     * @apiNote DateTimeOffset represents values to 100ns precision. If the java.time.OffsetDateTime instance represents
+     * a value that is more precise, values in excess of the 100ns precision are rounded to the nearest
+     * multiple of 100ns. Values within 50 nanoseconds of the next second are rounded up to the next second.
+     */
+    public static DateTimeOffset valueOf(java.time.OffsetDateTime offsetDateTime) {
+        return new DateTimeOffset(offsetDateTime);
+    }
+
     /** formatted value */
     private String formattedValue = null;
 

src/test/java/microsoft/sql/DateTimeOffsetTest.java

@@ -0,0 +1,51 @@
+/*
+ * Microsoft JDBC Driver for SQL Server Copyright(c) Microsoft Corporation All rights reserved. This program is made
+ * available under the terms of the MIT License. See the LICENSE file in the project root for more information.
+ */
+
+package microsoft.sql;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.time.OffsetDateTime;
+import java.time.ZoneOffset;
+
+public class DateTimeOffsetTest {
+
+    @Test
+    @DisplayName("DateTimeOffset.valueOf(offsetDateTime) instantiates correct DateTimeOffset instances.")
+    void valueOfOffsetDateTime() {
+        int nanos = 123456789;
+        int hundredNanos = 1234568; // DateTimeOffset has a precision of 100 nanos of second
+        OffsetDateTime offsetDateTime = OffsetDateTime.of(
+                2024,
+                2,
+                25,
+                23,
+                55,
+                6,
+                nanos,
+                ZoneOffset.ofHoursMinutes(1, 30)
+        );
+        Assertions
+                .assertEquals(
+                        offsetDateTime.withNano(hundredNanos * 100),
+                        DateTimeOffset.valueOf(offsetDateTime).getOffsetDateTime()
+                );
+    }
+
+    @Test
+    @DisplayName("DateTimeOffset.valueOf(offsetDateTime) correctly rounds up values within 50 nanoseconds of the next second.")
+    void valueOfOffsetDateTimeRounding() {
+        OffsetDateTime offsetDateTime = OffsetDateTime.now().withNano(999999950);
+        Assertions
+                .assertEquals(
+                        offsetDateTime
+                                .withSecond(offsetDateTime.getSecond() + 1)
+                                .withNano(0),
+                        DateTimeOffset.valueOf(offsetDateTime).getOffsetDateTime()
+                );
+    }
+}