public Set<Integer> getSequenceIDs() {
Set<Integer> ensemble = new HashSet<Integer>();
for (PseudoSequence sequence : getPseudoSequences()) {
ensemble.add(sequence.getId());
}
return ensemble;
}
@Override
public String toString() {
StringBuffer r = new StringBuffer("============ CONTEXTE ==========");
for (PseudoSequence sequence : pseudoSequences) { // pour chaque objet
r.append(sequence.getId());
r.append(": ");
r.append(sequence.toString());
r.append('\n');
}
return r.toString();
}
/**
* Method to find all frequent items in a projected sequence database
*
* @param sequences the set of sequences
* @return A list of pairs, where a pair is an item with (1) a boolean indicating if it is in an
* itemset that is "cut" and (2) the sequence IDs where it occurs.
*/
protected Set<Pair> findAllFrequentPairs(
SequentialPattern prefix, List<PseudoSequence> sequences) {
// We use a Map the store the pairs.
Map<Pair, Pair> mapPairs = new HashMap<Pair, Pair>();
// for each sequence
for (PseudoSequence sequence : sequences) {
// for each itemset
for (int i = 0; i < sequence.size(); i++) {
// for each item
for (int j = 0; j < sequence.getSizeOfItemsetAt(i); j++) {
String item = sequence.getItemAtInItemsetAt(j, i);
// create the pair corresponding to this item
Pair paire = new Pair(sequence.isPostfix(i), item); // false is ok?
// get the pair object store in the map if there is one already
Pair oldPaire = mapPairs.get(paire);
// if there is no pair object yet
if (oldPaire == null) {
// store the pair object that we created
mapPairs.put(paire, paire);
} else {
// otherwise use the old one
paire = oldPaire;
}
// record the current sequence id for that pair
paire.getSequencesID().add(sequence.getId());
}
}
}
MemoryLogger.getInstance().checkMemory(); // check the memory for statistics.
// return the map of pairs
return mapPairs.keySet();
}
/**
* Create a projected database by pseudo-projection
*
* @param item The item to use to make the pseudo-projection
* @param context The current database.
* @param inSuffix This boolean indicates if the item "item" is part of a suffix or not.
* @return the projected database.
*/
private List<PseudoSequence> buildProjectedContext(
String item, List<PseudoSequence> database, boolean inSuffix) {
// We create a new projected database
List<PseudoSequence> sequenceDatabase = new ArrayList<PseudoSequence>();
// for each sequence in the database received as parameter
for (PseudoSequence sequence : database) { // for each sequence
for (int i = 0; i < sequence.size(); i++) { // for each item of the sequence
// check if the itemset contains the item that we use for the projection
int index = sequence.indexOf(i, item);
// if it does not, and the current item is part of a suffix if inSuffix is true
// and vice-versa
if (index != -1 && sequence.isPostfix(i) == inSuffix) {
// if this is not the last item of the itemset of this sequence
if (index
!= sequence.getSizeOfItemsetAt(i)
- 1) { // if this is not the last item of the itemset
// create a new pseudo sequence
PseudoSequence newSequence = new PseudoSequence(sequence, i, index + 1);
if (newSequence.size() > 0) {
sequenceDatabase.add(newSequence);
}
} else if ((i
!= sequence.size() - 1)) { // if this is not the last itemset of the sequence
// create a new pseudo sequence
PseudoSequence newSequence = new PseudoSequence(sequence, i + 1, 0);
if (newSequence.size() > 0) {
// if the size of this pseudo sequence is greater than 0
// add it to the projected database.
sequenceDatabase.add(newSequence);
}
}
}
}
}
return sequenceDatabase; // return the projected database
}
