static void setComparator(Criteria criteria, String field, RawComparator<?> comparator) {
for (SortElement element : criteria.getElements()) {
if (element.getName().equals(field)) {
element.setCustomComparator(comparator);
}
}
}
protected static String[] getFirstFields(OrderBy sortCriteria, int numFields) {
String[] result = new String[numFields];
for (int i = 0; i < numFields; i++) {
SortElement element = sortCriteria.getElements().get(i);
result[i] = element.getName();
}
return result;
}
/** Initialize the custom comparators. Creates a quick access array for the custom comparators. */
private void initComparators() {
TupleMRConfigBuilder.initializeComparators(
context.getHadoopContext().getConfiguration(), tupleMRConfig);
customComparators = new RawComparator<?>[maxDepth + 1];
for (int i = minDepth; i <= maxDepth; i++) {
SortElement element = tupleMRConfig.getCommonCriteria().getElements().get(i);
if (element.getCustomComparator() != null) {
customComparators[i] = element.getCustomComparator();
}
}
}
/**
* Returns the fields that are a subset from the groupBy fields and will be used when rollup is
* needed.
*
* @see RollupReducer
*/
public List<String> calculateRollupBaseFields() {
if (rollupFrom == null) {
return getGroupByFields();
}
List<String> result = new ArrayList<String>();
for (SortElement element : commonCriteria.getElements()) {
result.add(element.getName());
if (element.getName().equals(rollupFrom)) {
break;
}
}
return result;
}
/** Returns the instance files created */
static Set<String> serializeComparators(
Criteria criteria,
Configuration conf,
List<String> comparatorRefs,
List<String> comparatorInstanceFiles,
String prefix)
throws TupleMRException {
Set<String> instanceFiles = new HashSet<String>();
if (criteria == null) {
return instanceFiles;
}
for (SortElement element : criteria.getElements()) {
if (element.getCustomComparator() != null) {
RawComparator<?> comparator = element.getCustomComparator();
if (!(comparator instanceof Serializable)) {
throw new TupleMRException(
"The class '"
+ comparator.getClass().getName()
+ "' is not Serializable."
+ " The customs comparators must implement Serializable.");
}
String ref = prefix + "|" + element.getName();
String uniqueName = UUID.randomUUID().toString() + '.' + "comparator.dat";
try {
InstancesDistributor.distribute(comparator, uniqueName, conf);
instanceFiles.add(uniqueName);
} catch (Exception e) {
throw new TupleMRException(
"The class " + comparator.getClass().getName() + " can't be serialized", e);
}
comparatorRefs.add(ref);
comparatorInstanceFiles.add(uniqueName);
}
}
return instanceFiles;
}