public ColumnAverageExpression() 
{
    this.returnInfinity = true; // for backward compatiblity.
    scale = 14;
    roundingMode = BigDecimal.ROUND_HALF_UP;
}

Default Constructor.

 public int getRoundingMode() 
{
    return roundingMode;
}

Returns the defined rounding mode. This influences the precision of the divide-operation.

 public int getScale() 
{
    return scale;
}

Returns the scale for the divide-operation. The scale influences the precision of the division.

 public Object getValue() 
{
    final Object[] values = getFieldValues();
    BigDecimal computedResult = new BigDecimal(0);
    int count = 0;
    for (int i = 0; i <  values.length; i++)
    {
      final Object value = values[i];
      if (value instanceof Number == false)
      {
        continue;
      }
      final Number n = (Number) value;
      final BigDecimal nval = new BigDecimal(n.toString());
      computedResult = computedResult.add(nval);
      count += 1;
    }
    if (onlyValidFields)
    {
      if (count == 0)
      {
        if (returnInfinity == false)
        {
          return null;
        }
        if (computedResult.signum() == -1)
        {
          return new Double(Double.NEGATIVE_INFINITY);
        }
        else
        {
          return new Double(Double.POSITIVE_INFINITY);
        }
      }
      return computedResult.divide(new BigDecimal(count), scale, roundingMode);
    }
    if (values.length == 0)
    {
      if (returnInfinity == false)
      {
        return null;
      }
      if (computedResult.signum() == -1)
      {
        return new Double(Double.NEGATIVE_INFINITY);
      }
      else
      {
        return new Double(Double.POSITIVE_INFINITY);
      }
    }
    return computedResult.divide(new BigDecimal(values.length), scale, roundingMode);
}

Computes the horizontal average of all field in the field-list. The average will be computed over all fields of the current data-row, it will not be computed for all rows in the group. For that use the org.jfree.report.function.ItemAvgFunction instead.

 public boolean isOnlyValidFields() 
{
    return onlyValidFields;
}

Returns, whether non-numeric and null-values are ignored for the average-computation.

 public boolean isReturnInfinity() 
{
    return returnInfinity;
}

Returns, whether the expression returns infinity if there are no valid fields. If set to false, this expression returns null instead.

 public  void setOnlyValidFields(boolean onlyValidFields) 
{
    this.onlyValidFields = onlyValidFields;
}

Defines, whether non-numeric and null-values are ignored for the average-computation.

 public  void setReturnInfinity(boolean returnInfinity) 
{
    this.returnInfinity = returnInfinity;
}

Defines, whether the expression returns infinity if there are no valid fields. If set to false, this expression returns null instead.

 public  void setRoundingMode(int roundingMode) 
{
    this.roundingMode = roundingMode;
}

Defines the rounding mode. This influences the precision of the divide-operation.

 public  void setScale(int scale) 
{
    this.scale = scale;
}

Defines the scale for the divide-operation. The scale influences the precision of the division.