apacheGH-38153: [C#] expose ArrayDataConcatenator.Concatenate (apache…

…#38154)

### Rationale for this change

New C# drivers need the ability to concatenate array data, particularly for metadata calls.

### What changes are included in this PR?

Converts a previously internal class and method to a public class and method.

### Are these changes tested?

Yes

### Are there any user-facing changes?

It exposes previously hidden functionality.

Resolves apache#38153
* Closes: apache#38153

Lead-authored-by: David Coe <coedavid@umich.edu>
Co-authored-by: davidhcoe <13318837+davidhcoe@users.noreply.github.com>
Signed-off-by: David Li <li.davidm96@gmail.com>

csharp/src/Apache.Arrow/Arrays/ArrayDataConcatenator.cs

@@ -20,9 +20,9 @@
 
 namespace Apache.Arrow
 {
- static class ArrayDataConcatenator
+ public class ArrayDataConcatenator
  {
- internal static ArrayData Concatenate(IReadOnlyList<ArrayData> arrayDataList, MemoryAllocator allocator = default)
+ public static ArrayData Concatenate(IReadOnlyList<ArrayData> arrayDataList, MemoryAllocator allocator = default)
  {
  if (arrayDataList == null || arrayDataList.Count == 0)
  {

csharp/test/Apache.Arrow.Tests/ArrayDataConcatenatorTests.cs

@@ -26,27 +26,17 @@ public class ArrayDataConcatenatorTests
  [Fact]
  public void TestNullOrEmpty()
  {
- Assert.Null(ArrayDataConcatenatorReflector.InvokeConcatenate(null));
- Assert.Null(ArrayDataConcatenatorReflector.InvokeConcatenate(new List<ArrayData>()));
+ Assert.Null(ArrayDataConcatenator.Concatenate(null));
+ Assert.Null(ArrayDataConcatenator.Concatenate(new List<ArrayData>()));
  }
 
  [Fact]
  public void TestSingleElement()
  {
  Int32Array array = new Int32Array.Builder().Append(1).Append(2).Build();
- ArrayData actualArray = ArrayDataConcatenatorReflector.InvokeConcatenate(new[] { array.Data });
+ ArrayData actualArray = ArrayDataConcatenator.Concatenate(new[] { array.Data });
  ArrowReaderVerifier.CompareArrays(array, ArrowArrayFactory.BuildArray(actualArray));
  }
 
- private static class ArrayDataConcatenatorReflector
- {
- private static readonly MethodInfo s_concatenateInfo = typeof(ArrayData).Assembly.GetType("Apache.Arrow.ArrayDataConcatenator")
- .GetMethod("Concatenate", BindingFlags.Static | BindingFlags.NonPublic);
-
- internal static ArrayData InvokeConcatenate(IReadOnlyList<ArrayData> arrayDataList, MemoryAllocator allocator = default)
- {
- return s_concatenateInfo.Invoke(null, new object[] { arrayDataList, allocator }) as ArrayData;
- }
- }
  }
 }