/**
* Decide whether the current title record should be displayed, based on whether it is a duplicate
* of the previous record, given the combination of output fields included in the ordering. If
* range fields are included in the output, or if identifying properties change between titles,
* the title will be shown.
*
* <p>If there are neither range fields nor id fields in the output, we can't tell if it is a
* duplicate so we show it anyway. Output with no id fields is pretty meaningless though.
*
* <p>Note that the method also sets the last output title if the response is true. Thus calling
* this method multiple times on the same title will give false after the first (unless there are
* no identifying fields).
*
* @param currentTitle the current title
* @return whether to show currentTitle
*/
public boolean isTitleForOutput(KbartTitle currentTitle) {
// The approach is to trueify this variable. If it becomes true, at the
// end of the method the lastOutputTitle is set before the result is
// returned. Do not return early!
boolean isOutput = false;
// Show title if it has no range or id fields by which we can decide duplicates
if (!rangeFieldsIncludedInDisplay && !idFieldsIncludedInDisplay) {
isOutput = true;
}
// Show the title if it is the first or the output includes range fields
if (lastOutputTitle == null || rangeFieldsIncludedInDisplay) {
isOutput = true;
} else if (!isOutput) { // don't do this check if we've already trueified the var
// At this point there are no range fields and this is not the first title
// Show the title if any visible idField differs between titles
for (Field f : idFields) {
if (visibleColumnOrdering.getFields().contains(f)
&& !lastOutputTitle.getField(f).equals(currentTitle.getField(f))) {
isOutput = true;
break;
}
}
}
// Finally, we refuse to output the title if it has no id and
// excludeNoIdTitles is true.
if (excludeNoIdTitles && StringUtil.isNullString(currentTitle.getField(Field.TITLE_ID)))
isOutput = false;
// Record the previous title
if (isOutput) lastOutputTitle = currentTitle;
return isOutput;
}
/**
* Calculate which fields have no values across the whole range of titles. Iterates through all
* the titles for each field value, until an entry is found or the end of the title list is
* reached.
*
* @return a set of fields which are empty
*/
private EnumSet<Field> findEmptyFields() {
long s = System.currentTimeMillis();
EnumSet<Field> empty = EnumSet.allOf(Field.class);
for (Field f : Field.getFieldSet()) {
// Check if any title has a value for this field
for (KbartTitle kbt : titles) {
if (kbt.hasFieldValue(f)) {
empty.remove(f);
break;
}
}
}
// Log the time, as this is an expensive way to monitor empty fields.
// It should be done somehow during title conversion.
log.debug("findEmptyFields() took " + (System.currentTimeMillis() - s) + "s");
return empty;
}
/**
* Get the value for a particular column, which is either the value of a field of the title, or
* a constant column value.
*
* @param title a KbartTitle providing values for the current row
* @return the value of a field in the title, or the label of a constant column
*/
public String getValue(KbartTitle title) {
return isField() ? title.getField(field) : label;
}