private void addToCluster(Map<Object, Cluster> clusters, Object fieldValue, Document document) {
if (fieldValue == null) {
return;
}
Cluster cluster = clusters.get(fieldValue);
if (cluster == null) {
cluster = new Cluster();
cluster.addPhrases(buildClusterLabel(fieldValue));
clusters.put(fieldValue, cluster);
}
cluster.addDocuments(document);
}
/** Performs by URL clustering. */
@Override
public void process() throws ProcessingException {
final Map<Object, Cluster> clusterMap = Maps.newHashMap();
for (Document document : documents) {
final Object field = document.getField(fieldName);
if (field instanceof Collection<?>) {
for (Object value : (Collection<?>) field) {
addToCluster(clusterMap, value, document);
}
} else {
addToCluster(clusterMap, field, document);
}
}
clusters = Lists.newArrayList(clusterMap.values());
Collections.sort(clusters, Cluster.BY_REVERSED_SIZE_AND_LABEL_COMPARATOR);
Cluster.appendOtherTopics(documents, clusters);
}