/**
* Determines the output format based on the input format and returns this.
*
* @param inputFormat the input format to base the output format on
* @return the output format
* @throws Exception in case the determination goes wrong
*/
protected Instances determineOutputFormat(Instances inputFormat) throws Exception {
Instances result;
Attribute att;
Attribute attSorted;
FastVector atts;
FastVector values;
Vector<String> sorted;
int i;
int n;
m_AttributeIndices.setUpper(inputFormat.numAttributes() - 1);
// determine sorted indices
atts = new FastVector();
m_NewOrder = new int[inputFormat.numAttributes()][];
for (i = 0; i < inputFormat.numAttributes(); i++) {
att = inputFormat.attribute(i);
if (!att.isNominal() || !m_AttributeIndices.isInRange(i)) {
m_NewOrder[i] = new int[0];
atts.addElement(inputFormat.attribute(i).copy());
continue;
}
// sort labels
sorted = new Vector<String>();
for (n = 0; n < att.numValues(); n++) sorted.add(att.value(n));
Collections.sort(sorted, m_Comparator);
// determine new indices
m_NewOrder[i] = new int[att.numValues()];
values = new FastVector();
for (n = 0; n < att.numValues(); n++) {
m_NewOrder[i][n] = sorted.indexOf(att.value(n));
values.addElement(sorted.get(n));
}
attSorted = new Attribute(att.name(), values);
attSorted.setWeight(att.weight());
atts.addElement(attSorted);
}
// generate new header
result = new Instances(inputFormat.relationName(), atts, 0);
result.setClassIndex(inputFormat.classIndex());
return result;
}
/**
* Set the output format. Swapss the desired nominal attribute values in the header and calls
* setOutputFormat(Instances) appropriately.
*/
private void setOutputFormat() {
Instances newData;
ArrayList<Attribute> newAtts;
ArrayList<String> newVals;
// Compute new attributes
newAtts = new ArrayList<Attribute>(getInputFormat().numAttributes());
for (int j = 0; j < getInputFormat().numAttributes(); j++) {
Attribute att = getInputFormat().attribute(j);
if (j != m_AttIndex.getIndex()) {
newAtts.add((Attribute) att.copy());
} else {
// Compute list of attribute values
newVals = new ArrayList<String>(att.numValues());
for (int i = 0; i < att.numValues(); i++) {
if (i == m_FirstIndex.getIndex()) {
newVals.add(att.value(m_SecondIndex.getIndex()));
} else if (i == m_SecondIndex.getIndex()) {
newVals.add(att.value(m_FirstIndex.getIndex()));
} else {
newVals.add(att.value(i));
}
}
Attribute newAtt = new Attribute(att.name(), newVals);
newAtt.setWeight(att.weight());
newAtts.add(newAtt);
}
}
// Construct new header
newData = new Instances(getInputFormat().relationName(), newAtts, 0);
newData.setClassIndex(getInputFormat().classIndex());
setOutputFormat(newData);
}