/**
* Seeks for recurring element in a parsed document which are likely candidates for being data
* records
*
* @param parser The parser loaded with tree data
* @return The path to the most numerous of the possible candidates. null if no candidates were
* found (less than 6 recurrences)
*/
public static String[] detectRecordElement(TreeReader parser) {
logger.trace("detectRecordElement(inputStream)");
List<RecordElementCandidate> candidates = new ArrayList<RecordElementCandidate>();
try {
while (parser.hasNext()) {
Token eventType = parser.next();
if (eventType == Token.StartEntity) {
RecordElementCandidate candidate =
detectRecordElement(parser, new String[] {parser.getFieldName()});
if (candidate != null) {
candidates.add(candidate);
}
}
}
} catch (TreeReaderException e) {
// silent
e.printStackTrace();
}
if (candidates.size() > 0) {
sortRecordElementCandidates(candidates);
return candidates.get(0).path;
}
logger.info(
"No candidate elements were found in data - at least 6 similar elements are required");
return null;
}
protected static RecordElementCandidate detectRecordElement(TreeReader parser, String[] path) {
logger.trace("detectRecordElement(TreeReader, String[])");
List<RecordElementCandidate> descendantCandidates = new ArrayList<RecordElementCandidate>();
Map<String, Integer> immediateChildCandidateMap = new HashMap<String, Integer>();
try {
while (parser.hasNext()) {
Token eventType = parser.next();
if (eventType == Token.EndEntity) {
break;
} else if (eventType == Token.StartEntity) {
String tagName = parser.getFieldName();
immediateChildCandidateMap.put(
tagName,
immediateChildCandidateMap.containsKey(tagName)
? immediateChildCandidateMap.get(tagName) + 1
: 1);
String[] path2 = new String[path.length + 1];
System.arraycopy(path, 0, path2, 0, path.length);
path2[path.length] = tagName;
RecordElementCandidate c = detectRecordElement(parser, path2);
if (c != null) {
descendantCandidates.add(c);
}
}
}
} catch (TreeReaderException e) {
// silent
e.printStackTrace();
}
if (immediateChildCandidateMap.size() > 0) {
List<RecordElementCandidate> immediateChildCandidates =
new ArrayList<RecordElementCandidate>(immediateChildCandidateMap.size());
for (Entry<String, Integer> entry : immediateChildCandidateMap.entrySet()) {
int count = entry.getValue();
if (count > 1) {
String[] path2 = new String[path.length + 1];
System.arraycopy(path, 0, path2, 0, path.length);
path2[path.length] = entry.getKey();
RecordElementCandidate candidate = new RecordElementCandidate();
candidate.path = path2;
candidate.count = count;
immediateChildCandidates.add(candidate);
}
}
if (immediateChildCandidates.size() > 0 && immediateChildCandidates.size() < 5) {
// There are some promising immediate child elements, but not many,
// that can serve as record elements.
sortRecordElementCandidates(immediateChildCandidates);
RecordElementCandidate ourCandidate = immediateChildCandidates.get(0);
logger.trace(
"ourCandidate.count : "
+ ourCandidate.count
+ "; immediateChildCandidates.size() : "
+ immediateChildCandidates.size());
if (ourCandidate.count / immediateChildCandidates.size() > 5) {
return ourCandidate;
}
descendantCandidates.add(ourCandidate);
}
}
if (descendantCandidates.size() > 0) {
sortRecordElementCandidates(descendantCandidates);
RecordElementCandidate candidate = descendantCandidates.get(0);
if (candidate.count / descendantCandidates.size() > 5) {
return candidate;
}
}
return null;
}