private Trail handleDefaultChild(Trail trail, Node node, EvaluationContext context) {
// "The defaultChild missing value strategy requires the presence of the defaultChild attribute
// in every non-leaf Node"
String defaultChild = node.getDefaultChild();
if (defaultChild == null) {
throw new InvalidFeatureException(node);
}
trail.addMissingLevel();
List<Node> children = node.getNodes();
for (int i = 0, max = children.size(); i < max; i++) {
Node child = children.get(i);
String id = child.getId();
if (id != null && (id).equals(defaultChild)) {
// The predicate of the referenced Node is not evaluated
return handleTrue(trail, child, context);
}
}
// "Only Nodes which are immediate children of the respective Node can be referenced"
throw new InvalidFeatureException(node);
}
private Trail handleTrue(Trail trail, Node node, EvaluationContext context) {
// A "true" leaf node
if (!node.hasNodes()) {
return trail.selectNode(node);
}
trail.push(node);
List<Node> children = node.getNodes();
for (int i = 0, max = children.size(); i < max; i++) {
Node child = children.get(i);
Boolean status = evaluateNode(trail, child, context);
if (status == null) {
Trail destination = handleMissingValue(trail, node, child, context);
if (destination != null) {
return destination;
}
} else if (status.booleanValue()) {
return handleTrue(trail, child, context);
}
}
// A "true" non-leaf node
return handleNoTrueChild(trail);
}
private Boolean evaluateNode(Trail trail, Node node, EvaluationContext context) {
EmbeddedModel embeddedModel = node.getEmbeddedModel();
if (embeddedModel != null) {
throw new UnsupportedFeatureException(embeddedModel);
}
Predicate predicate = node.getPredicate();
if (predicate == null) {
throw new InvalidFeatureException(node);
} // End if
// A compound predicate whose boolean operator is "surrogate" represents a special case
if (predicate instanceof CompoundPredicate) {
CompoundPredicate compoundPredicate = (CompoundPredicate) predicate;
PredicateUtil.CompoundPredicateResult result =
PredicateUtil.evaluateCompoundPredicateInternal(compoundPredicate, context);
if (result.isAlternative()) {
trail.addMissingLevel();
}
return result.getResult();
} else {
return PredicateUtil.evaluate(predicate, context);
}
}
private ImmutableBiMap.Builder<String, Node> collectNodes(
Node node, AtomicInteger index, ImmutableBiMap.Builder<String, Node> builder) {
builder = EntityUtil.put(node, index, builder);
if (!node.hasNodes()) {
return builder;
}
List<Node> children = node.getNodes();
for (Node child : children) {
builder = collectNodes(child, index, builder);
}
return builder;
}
private Map<FieldName, ?> evaluateRegression(ModelEvaluationContext context) {
Trail trail = new Trail();
Node node = evaluateTree(trail, context);
if (node == null) {
return TargetUtil.evaluateRegressionDefault(context);
}
Double score = (Double) TypeUtil.parseOrCast(DataType.DOUBLE, node.getScore());
TargetField targetField = getTargetField();
NodeScore nodeScore =
createNodeScore(node, TargetUtil.evaluateRegressionInternal(targetField, score, context));
return Collections.singletonMap(targetField.getName(), nodeScore);
}
private NodeScoreDistribution createNodeScoreDistribution(Node node, double missingValuePenalty) {
BiMap<String, Node> entityRegistry = getEntityRegistry();
NodeScoreDistribution result = new NodeScoreDistribution(entityRegistry, node);
if (!node.hasScoreDistributions()) {
return result;
}
List<ScoreDistribution> scoreDistributions = node.getScoreDistributions();
double sum = 0;
for (int i = 0, max = scoreDistributions.size(); i < max; i++) {
ScoreDistribution scoreDistribution = scoreDistributions.get(i);
Double recordCount = scoreDistribution.getRecordCount();
if (recordCount == null) {
throw new InvalidFeatureException(scoreDistribution);
}
sum += recordCount;
} // End for
for (int i = 0, max = scoreDistributions.size(); i < max; i++) {
ScoreDistribution scoreDistribution = scoreDistributions.get(i);
Double probability = scoreDistribution.getProbability();
if (probability == null) {
Double recordCount = scoreDistribution.getRecordCount();
probability = (recordCount / sum);
}
result.put(scoreDistribution.getValue(), probability);
Double confidence = scoreDistribution.getConfidence();
if (confidence != null) {
result.putConfidence(scoreDistribution.getValue(), confidence * missingValuePenalty);
}
}
return result;
}
private Trail handleNoTrueChild(Trail trail) {
TreeModel treeModel = getModel();
TreeModel.NoTrueChildStrategy noTrueChildStrategy = treeModel.getNoTrueChildStrategy();
switch (noTrueChildStrategy) {
case RETURN_NULL_PREDICTION:
return trail.selectNull();
case RETURN_LAST_PREDICTION:
Node lastPrediction = trail.getLastPrediction();
// "Return the parent Node only if it specifies a score attribute"
if (lastPrediction.hasScore()) {
return trail.selectLastPrediction();
}
return trail.selectNull();
default:
throw new UnsupportedFeatureException(treeModel, noTrueChildStrategy);
}
}
private Node evaluateTree(Trail trail, EvaluationContext context) {
TreeModel treeModel = getModel();
Node root = treeModel.getNode();
Boolean status = evaluateNode(trail, root, context);
if (status != null && status.booleanValue()) {
trail = handleTrue(trail, root, context);
Node node = trail.getResult();
// "It is not possible that the scoring process ends in a Node which does not have a score
// attribute"
if (node != null && !node.hasScore()) {
throw new InvalidFeatureException(node);
}
return node;
}
return null;
}