private void checkStemming(Schema schema, FieldSet fieldSet) {
        Stemming stemming = null;
        for (String fieldName : fieldSet.getFieldNames()) {
            ImmutableSDField field = schema.getField(fieldName);
            Stemming fieldStemming = field.getStemming();
            if (stemming == null) {
                stemming = fieldStemming;
            } else {
                if ( ! stemming.equals(fieldStemming)) {
                    warn(schema, field.asField(),
                            "The stemming settings for the fields in the fieldset '"+fieldSet.getName()+
                                    "' are inconsistent (explicitly or because of field type). " +
                                    "This may lead to recall and ranking issues. " +
                                    "See " + fieldSetDocUrl);
                }
            }
        }
    }
Computes the right "index commands" for each fieldset in a search definition.

@author vegardh
@author bratseth
config-model/src/main/java/com/yahoo/schema/processing/FieldSetSettings.java