[Java] VectorSchemaRoot#addVector() cannot add a vector to the end of the current vector collection

[asfimport]

The current implementation of Java VectorSchemaRoot cannot add a vector at the end of the current list (which is the generally understood meaning of "add").

The Precondition check in the method's second line prevents providing an appropriate index for adding at the end:

public VectorSchemaRoot addVector(int index, FieldVector vector) {
  Preconditions.checkNotNull(vector);
  Preconditions.checkArgument(index >= 0 && index < fieldVectors.size());
  List<FieldVector> newVectors = new ArrayList<>();
  for (int i = 0; i < fieldVectors.size(); i++) {
    if (i == index) {
      newVectors.add(vector);
    }
    newVectors.add(fieldVectors.get(i));
  }
  return new VectorSchemaRoot(newVectors);
}

One possible implementation resolving the issue is shown below.

public VectorSchemaRoot addVector(int index, FieldVector vector) {
  Preconditions.checkNotNull(vector);
  Preconditions.checkArgument(index >= 0 && index <= fieldVectors.size());
  List<FieldVector> newVectors = new ArrayList<>();
  if (index == fieldVectors.size()) {
    newVectors.addAll(fieldVectors);
    newVectors.add(vector); 
  } else {
    for (int i = 0; i < fieldVectors.size(); i++) {
      if (i == index) {
        newVectors.add(vector);
      }
      newVectors.add(fieldVectors.get(i));
    }
  }
  return new VectorSchemaRoot(newVectors);
}

 

 

 

 

 

Reporter: Larry White / @lwhite1

_{Note: This issue was originally created as ARROW-17530. Please see the migration documentation for further details.}

[asfimport]

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