/**
* Calculates the sum of a given field.
*
* @param fieldName the field to sum. Only number fields are supported.
* @return the sum. If no objects exist or they all have {@code null} as the value for the given
* field, {@code 0} will be returned. When computing the sum, objects with {@code null} values
* are ignored.
* @throws java.lang.IllegalArgumentException if the field is not a number type.
*/
public Number sum(String fieldName) {
realm.checkIfValid();
long columnIndex = table.getColumnIndex(fieldName);
switch (table.getColumnType(columnIndex)) {
case INTEGER:
return table.sumLong(columnIndex);
case FLOAT:
return table.sumFloat(columnIndex);
case DOUBLE:
return table.sumDouble(columnIndex);
default:
throw new IllegalArgumentException(
String.format(TYPE_MISMATCH, fieldName, "int, float or double"));
}
}
