Improve Trino to Iceberg conversion code

- suppress intentional "redundant casts"
- exact division
- cast to primitive directly (looks nicer, same meaning)
- remove redundant `instanceof`
- put decimals together with other numbers

plugin/trino-iceberg/src/main/java/io/trino/plugin/iceberg/IcebergTypes.java

@@ -13,18 +13,13 @@
  */
 package io.trino.plugin.iceberg;
 
+import com.google.common.math.LongMath;
 import io.airlift.slice.Slice;
 import io.airlift.slice.Slices;
-import io.trino.spi.type.BigintType;
-import io.trino.spi.type.BooleanType;
-import io.trino.spi.type.DateType;
 import io.trino.spi.type.DecimalType;
 import io.trino.spi.type.Decimals;
-import io.trino.spi.type.DoubleType;
 import io.trino.spi.type.Int128;
-import io.trino.spi.type.IntegerType;
 import io.trino.spi.type.LongTimestampWithTimeZone;
-import io.trino.spi.type.RealType;
 import io.trino.spi.type.UuidType;
 import io.trino.spi.type.VarbinaryType;
 import io.trino.spi.type.VarcharType;
@@ -39,6 +34,12 @@
 import static io.airlift.slice.Slices.utf8Slice;
 import static io.trino.plugin.iceberg.util.Timestamps.timestampTzFromMicros;
 import static io.trino.plugin.iceberg.util.Timestamps.timestampTzToMicros;
+import static io.trino.spi.type.BigintType.BIGINT;
+import static io.trino.spi.type.BooleanType.BOOLEAN;
+import static io.trino.spi.type.DateType.DATE;
+import static io.trino.spi.type.DoubleType.DOUBLE;
+import static io.trino.spi.type.IntegerType.INTEGER;
+import static io.trino.spi.type.RealType.REAL;
 import static io.trino.spi.type.TimeType.TIME_MICROS;
 import static io.trino.spi.type.TimestampType.TIMESTAMP_MICROS;
 import static io.trino.spi.type.TimestampWithTimeZoneType.TIMESTAMP_TZ_MICROS;
@@ -49,6 +50,7 @@
 import static java.lang.Float.intBitsToFloat;
 import static java.lang.Math.multiplyExact;
 import static java.lang.Math.toIntExact;
+import static java.math.RoundingMode.UNNECESSARY;
 import static java.util.Objects.requireNonNull;
 
 public final class IcebergTypes
@@ -64,35 +66,46 @@ public static Object convertTrinoValueToIceberg(io.trino.spi.type.Type type, Obj
     {
         requireNonNull(trinoNativeValue, "trinoNativeValue is null");
 
-        if (type instanceof BooleanType) {
+        if (type == BOOLEAN) {
+            //noinspection RedundantCast
             return (boolean) trinoNativeValue;
         }
 
-        if (type instanceof IntegerType) {
+        if (type == INTEGER) {
             return toIntExact((long) trinoNativeValue);
         }
 
-        if (type instanceof BigintType) {
+        if (type == BIGINT) {
+            //noinspection RedundantCast
             return (long) trinoNativeValue;
         }
 
-        if (type instanceof RealType) {
+        if (type == REAL) {
             return intBitsToFloat(toIntExact((long) trinoNativeValue));
         }
 
-        if (type instanceof DoubleType) {
+        if (type == DOUBLE) {
+            //noinspection RedundantCast
             return (double) trinoNativeValue;
         }
 
-        if (type instanceof DateType) {
-            return toIntExact(((Long) trinoNativeValue));
+        if (type instanceof DecimalType decimalType) {
+            if (decimalType.isShort()) {
+                return BigDecimal.valueOf((long) trinoNativeValue).movePointLeft(decimalType.getScale());
+            }
+            return new BigDecimal(((Int128) trinoNativeValue).toBigInteger(), decimalType.getScale());
+        }
+
+        if (type == DATE) {
+            return toIntExact((long) trinoNativeValue);
         }
 
         if (type.equals(TIME_MICROS)) {
-            return ((long) trinoNativeValue) / PICOSECONDS_PER_MICROSECOND;
+            return LongMath.divide((long) trinoNativeValue, PICOSECONDS_PER_MICROSECOND, UNNECESSARY);
         }
 
         if (type.equals(TIMESTAMP_MICROS)) {
+            //noinspection RedundantCast
             return (long) trinoNativeValue;
         }
 
@@ -108,17 +121,10 @@ public static Object convertTrinoValueToIceberg(io.trino.spi.type.Type type, Obj
             return ByteBuffer.wrap(((Slice) trinoNativeValue).getBytes());
         }
 
-        if (type instanceof UuidType) {
+        if (type == UuidType.UUID) {
             return trinoUuidToJavaUuid(((Slice) trinoNativeValue));
         }
 
-        if (type instanceof DecimalType decimalType) {
-            if (decimalType.isShort()) {
-                return BigDecimal.valueOf((long) trinoNativeValue).movePointLeft(decimalType.getScale());
-            }
-            return new BigDecimal(((Int128) trinoNativeValue).toBigInteger(), decimalType.getScale());
-        }
-
         throw new UnsupportedOperationException("Unsupported type: " + type);
     }