Remove static array

src/Apache.Arrow/Types/DurationType.cs

@@ -13,6 +13,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+using System;
+
 namespace Apache.Arrow.Types
 {
     public sealed class DurationType : TimeBasedType
@@ -21,7 +23,6 @@ public sealed class DurationType : TimeBasedType
         public static readonly DurationType Millisecond = new DurationType(TimeUnit.Millisecond);
         public static readonly DurationType Microsecond = new DurationType(TimeUnit.Microsecond);
         public static readonly DurationType Nanosecond = new DurationType(TimeUnit.Nanosecond);
-        private static readonly DurationType[] _types = new DurationType[] { Second, Millisecond, Microsecond, Nanosecond };
 
         private DurationType(TimeUnit unit)
             : base(unit)
@@ -32,10 +33,14 @@ private DurationType(TimeUnit unit)
         public override string Name => "duration";
         public override int BitWidth => 64;
 
-        public static DurationType FromTimeUnit(TimeUnit unit)
+        public static DurationType FromTimeUnit(TimeUnit unit) => unit switch
         {
-            return _types[(int)unit];
-        }
+            TimeUnit.Second => Second,
+            TimeUnit.Millisecond => Millisecond,
+            TimeUnit.Microsecond => Microsecond,
+            TimeUnit.Nanosecond => Nanosecond,
+            _ => throw new ArgumentOutOfRangeException(nameof(unit), unit, @"Unsupported time unit.")
+        };
 
         public override void Accept(IArrowTypeVisitor visitor) => Accept(this, visitor);
     }

src/Apache.Arrow/Types/IntervalType.cs

@@ -22,7 +22,6 @@ public sealed class IntervalType : FixedWidthType
         public static readonly IntervalType YearMonth = new IntervalType(IntervalUnit.YearMonth);
         public static readonly IntervalType DayTime = new IntervalType(IntervalUnit.DayTime);
         public static readonly IntervalType MonthDayNanosecond = new IntervalType(IntervalUnit.MonthDayNanosecond);
-        private static readonly IntervalType[] _types = new IntervalType[] { YearMonth, DayTime, MonthDayNanosecond };
 
         public override ArrowTypeId TypeId => ArrowTypeId.Interval;
         public override string Name => "interval";
@@ -43,9 +42,12 @@ public IntervalType(IntervalUnit unit = IntervalUnit.YearMonth)
 
         public override void Accept(IArrowTypeVisitor visitor) => Accept(this, visitor);
 
-        public static IntervalType FromIntervalUnit(IntervalUnit unit)
+        public static IntervalType FromIntervalUnit(IntervalUnit unit) => unit switch
         {
-            return _types[(int)unit];
-        }
+            IntervalUnit.YearMonth => YearMonth,
+            IntervalUnit.DayTime => DayTime,
+            IntervalUnit.MonthDayNanosecond => MonthDayNanosecond,
+            _ => throw new ArgumentOutOfRangeException(nameof(unit), unit, @"Unsupported interval unit")
+        };
     }
 }

src/Apache.Arrow/Types/TimeType.cs

@@ -13,6 +13,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+using System;
+
 namespace Apache.Arrow.Types
 {
     public abstract class TimeType : TimeBasedType
@@ -21,16 +23,19 @@ public abstract class TimeType : TimeBasedType
         public static readonly Time32Type Millisecond = new Time32Type(TimeUnit.Millisecond);
         public static readonly Time64Type Microsecond = new Time64Type(TimeUnit.Microsecond);
         public static readonly Time64Type Nanosecond = new Time64Type(TimeUnit.Nanosecond);
-        private static readonly TimeType[] _types = new TimeType[] { Second, Millisecond, Microsecond, Nanosecond };
 
         protected TimeType(TimeUnit unit)
             : base(unit)
         {
         }
 
-        public static TimeType FromTimeUnit(TimeUnit unit)
+        public static TimeType FromTimeUnit(TimeUnit unit) => unit switch
         {
-            return _types[(int)unit];
-        }
+            TimeUnit.Second => Second,
+            TimeUnit.Millisecond => Millisecond,
+            TimeUnit.Microsecond => Microsecond,
+            TimeUnit.Nanosecond => Nanosecond,
+            _ => throw new ArgumentOutOfRangeException(nameof(unit), unit, @"Unsupported time unit")
+        };
     }
 }