Implemented an OffsetDateTime-to-GregorianCalendar converter

diff --git a/src/main/java/de/juplo/jpa/converters/OffsetDateTimeConverter.java b/src/main/java/de/juplo/jpa/converters/OffsetDateTimeConverter.java
new file mode 100644 (file)
index 0000000..d49da18
--- /dev/null
+++ b/src/main/java/de/juplo/jpa/converters/OffsetDateTimeConverter.java
@@ -0,0 +1,35 @@
+package de.juplo.jpa.converters;
+
+import java.time.OffsetDateTime;
+import java.time.ZonedDateTime;
+import java.util.GregorianCalendar;
+import javax.persistence.AttributeConverter;
+import javax.persistence.Converter;
+
+
+/**
+ * Converts a {@link OffsetDateTime} to a {@link GregorianCalendar}, by first
+ * converting it into a {@link ZonedDateTime} and then converting it as
+ * suggested in the official Java 8 Time tutorial.
+ * <p>
+ * The {@link GregorianCalendar} can then be persisted as
+ * {@link java.persistene.TemporalType.TIMESTAMP} with the help of the
+ * {@link java.persist.Tmporal}-annotation.
+ * @see https://docs.oracle.com/javase/tutorial/datetime/iso/legacy.html
+ * @author Kai Moritz
+ */
+@Converter(autoApply = true)
+public class OffsetDateTimeConverter implements AttributeConverter<OffsetDateTime, GregorianCalendar>
+{
+  @Override
+  public GregorianCalendar convertToDatabaseColumn(OffsetDateTime odt)
+  {
+    return GregorianCalendar.from(ZonedDateTime.from(odt));
+  }
+
+  @Override
+  public OffsetDateTime convertToEntityAttribute(GregorianCalendar calendar)
+  {
+    return OffsetDateTime.from(calendar.toZonedDateTime());
+  }
+}