[Java]: Expose util methods inside VectorAppender class such as append vector values

[davisusanibar]

Describe the enhancement requested

Current VectorAppender class is package-private.

This class provides utility methods for appending vector values fields that can be exposed publicly.

Java code:

    package org.apache.arrow.vector.util;
    import org.apache.arrow.memory.BufferAllocator;
    import org.apache.arrow.memory.RootAllocator;
    import org.apache.arrow.vector.IntVector;
    import org.apache.arrow.vector.ValueVector;
    public class FieldVectorAppender {
      public static void main(String[] args) {
        try (
            BufferAllocator allocator = new RootAllocator();
            IntVector initialValues = new IntVector("initialValues", allocator);
            IntVector toAppend = new IntVector("toAppend", allocator);
        ) {
          initialValues.allocateNew(2);
          initialValues.set(0, 1);
          initialValues.set(1, 2);
          initialValues.setValueCount(2);
          System.out.println("Initial IntVector: " + initialValues);
          toAppend.allocateNew(4);
          toAppend.set(1, 4);
          toAppend.set(3, 6);
          toAppend.setValueCount(4);
          System.out.println("IntVector to Append: " + toAppend);
          VectorAppender appenderUtil = new VectorAppender(initialValues);
          ValueVector resultOfVectorsAppended = toAppend.accept(appenderUtil, null);
          System.out.println("IntVector Result: " + resultOfVectorsAppended);
        }
      }
    }

Result:

    Initial IntVector: [1, 2]
    IntVector to Append: [null, 4, null, 6]
    IntVector Result: [1, 2, null, 4, null, 6]

Component(s)

Java