Use LocalDateTime.toLocalTime() instead of obscured calculations in LocalDateTimeUtils

h2/src/main/org/h2/util/LocalDateTimeUtils.java

@@ -85,8 +85,8 @@ public class LocalDateTimeUtils {
     private static final Method LOCAL_DATE_TIME_PLUS_NANOS;
     // java.time.LocalDateTime#toLocalDate()
     private static final Method LOCAL_DATE_TIME_TO_LOCAL_DATE;
-    // java.time.LocalDateTime#truncatedTo(TemporalUnit)
-    private static final Method LOCAL_DATE_TIME_TRUNCATED_TO;
+    // java.time.LocalDateTime#toLocalTime()
+    private static final Method LOCAL_DATE_TIME_TO_LOCAL_TIME;
     // java.time.LocalDateTime#parse(CharSequence)
     private static final Method LOCAL_DATE_TIME_PARSE;
 
@@ -105,17 +105,8 @@ public class LocalDateTimeUtils {
     // java.time.ZoneOffset#getTotalSeconds()
     private static final Method ZONE_OFFSET_GET_TOTAL_SECONDS;
 
-    // java.time.Duration#between(Temporal, Temporal)
-    private static final Method DURATION_BETWEEN;
-    // java.time.Duration#toNanos()
-    private static final Method DURATION_TO_NANOS;
-
-    // java.time.temporal.ChronoUnit#DAYS
-    private static final Object CHRONO_UNIT_DAYS;
-
     private static final boolean IS_JAVA8_DATE_API_PRESENT;
 
-
     static {
         LOCAL_DATE = tryGetClass("java.time.LocalDate");
         LOCAL_TIME = tryGetClass("java.time.LocalTime");
@@ -127,12 +118,6 @@ public class LocalDateTimeUtils {
                 ZONE_OFFSET != null;
 
         if (IS_JAVA8_DATE_API_PRESENT) {
-
-            Class<?> temporalUnit = getClass("java.time.temporal.TemporalUnit");
-            Class<?> chronoUnit = getClass("java.time.temporal.ChronoUnit");
-            Class<?> duration = getClass("java.time.Duration");
-            Class<?> temporal = getClass("java.time.temporal.Temporal");
-
             LOCAL_TIME_OF_NANO = getMethod(LOCAL_TIME, "ofNanoOfDay", long.class);
 
             LOCAL_TIME_TO_NANO = getMethod(LOCAL_TIME, "toNanoOfDay");
@@ -150,7 +135,7 @@ public class LocalDateTimeUtils {
 
             LOCAL_DATE_TIME_PLUS_NANOS = getMethod(LOCAL_DATE_TIME, "plusNanos", long.class);
             LOCAL_DATE_TIME_TO_LOCAL_DATE = getMethod(LOCAL_DATE_TIME, "toLocalDate");
-            LOCAL_DATE_TIME_TRUNCATED_TO = getMethod(LOCAL_DATE_TIME, "truncatedTo", temporalUnit);
+            LOCAL_DATE_TIME_TO_LOCAL_TIME = getMethod(LOCAL_DATE_TIME, "toLocalTime");
             LOCAL_DATE_TIME_PARSE = getMethod(LOCAL_DATE_TIME, "parse", CharSequence.class);
 
             ZONE_OFFSET_OF_TOTAL_SECONDS = getMethod(ZONE_OFFSET, "ofTotalSeconds", int.class);
@@ -162,11 +147,6 @@ public class LocalDateTimeUtils {
             OFFSET_DATE_TIME_PARSE = getMethod(OFFSET_DATE_TIME, "parse", CharSequence.class);
 
             ZONE_OFFSET_GET_TOTAL_SECONDS = getMethod(ZONE_OFFSET, "getTotalSeconds");
-
-            DURATION_BETWEEN = getMethod(duration, "between", temporal, temporal);
-            DURATION_TO_NANOS = getMethod(duration, "toNanos");
-
-            CHRONO_UNIT_DAYS = getFieldValue(chronoUnit, "DAYS");
         } else {
             LOCAL_TIME_OF_NANO = null;
             LOCAL_TIME_TO_NANO = null;
@@ -179,7 +159,7 @@ public class LocalDateTimeUtils {
             LOCAL_TIME_PARSE = null;
             LOCAL_DATE_TIME_PLUS_NANOS = null;
             LOCAL_DATE_TIME_TO_LOCAL_DATE = null;
-            LOCAL_DATE_TIME_TRUNCATED_TO = null;
+            LOCAL_DATE_TIME_TO_LOCAL_TIME = null;
             LOCAL_DATE_TIME_PARSE = null;
             ZONE_OFFSET_OF_TOTAL_SECONDS = null;
             OFFSET_DATE_TIME_TO_LOCAL_DATE_TIME = null;
@@ -187,9 +167,6 @@ public class LocalDateTimeUtils {
             OFFSET_DATE_TIME_OF_LOCAL_DATE_TIME_ZONE_OFFSET = null;
             OFFSET_DATE_TIME_PARSE = null;
             ZONE_OFFSET_GET_TOTAL_SECONDS = null;
-            DURATION_BETWEEN = null;
-            DURATION_TO_NANOS = null;
-            CHRONO_UNIT_DAYS = null;
         }
     }
 
@@ -310,15 +287,6 @@ public class LocalDateTimeUtils {
         }
     }
 
-    private static Class<?> getClass(String className) {
-        try {
-            return Class.forName(className);
-        } catch (ClassNotFoundException e) {
-            throw new IllegalStateException("Java 8 or later but class " +
-                    className + " is missing", e);
-        }
-    }
-
     private static Method getMethod(Class<?> clazz, String methodName,
             Class<?>... parameterTypes) {
         try {
@@ -330,15 +298,6 @@ public class LocalDateTimeUtils {
         }
     }
 
-    private static Object getFieldValue(Class<?> clazz, String fieldName) {
-        try {
-            return clazz.getField(fieldName).get(null);
-        } catch (NoSuchFieldException | IllegalAccessException e) {
-            throw new IllegalStateException("Java 8 or later but field " +
-                    clazz.getName() + "#" + fieldName + " is missing", e);
-        }
-    }
-
     /**
      * Checks if the given class is LocalDate.
      *
@@ -566,9 +525,8 @@ public class LocalDateTimeUtils {
 
     private static long timeNanosFromLocalDateTime(Object localDateTime)
                     throws IllegalAccessException, InvocationTargetException {
-        Object midnight = LOCAL_DATE_TIME_TRUNCATED_TO.invoke(localDateTime, CHRONO_UNIT_DAYS);
-        Object duration = DURATION_BETWEEN.invoke(null, midnight, localDateTime);
-        return (Long) DURATION_TO_NANOS.invoke(duration);
+        Object localTime = LOCAL_DATE_TIME_TO_LOCAL_TIME.invoke(localDateTime);
+        return (Long) LOCAL_TIME_TO_NANO.invoke(localTime);
     }
 
     private static short zoneOffsetToOffsetMinute(Object zoneOffset)