private VectorizedRowBatch makeTrimBatch() {
    VectorizedRowBatch b = new VectorizedRowBatch(2);
    BytesColumnVector inV = new BytesColumnVector();
    BytesColumnVector outV = new BytesColumnVector();
    b.cols[0] = inV;
    b.cols[1] = outV;
    inV.setRef(0, emptyString, 0, 0);
    inV.setRef(1, blanksLeft, 0, blanksLeft.length);
    inV.setRef(2, blanksRight, 0, blanksRight.length);
    inV.setRef(3, blanksBoth, 0, blanksBoth.length);
    inV.setRef(4, red, 0, red.length);
    inV.setRef(5, blankString, 0, blankString.length);
    b.size = 5;
    return b;
  }
Test vectorized expression and filter evaluation for strings.
ql/src/test/org/apache/hadoop/hive/ql/exec/vector/expressions/TestVectorStringExpressions.java