static void deserializeComparators(Configuration conf, TupleMRConfig mrConfig)
throws TupleMRException {
String[] comparatorRefs = conf.getStrings(CONF_COMPARATOR_REFERENCES);
String[] comparatorInstanceFiles = conf.getStrings(CONF_COMPARATOR_INSTANCES);
if (comparatorRefs == null) {
return;
}
try {
for (int i = 0; i < comparatorRefs.length; i++) {
String[] ref = comparatorRefs[i].split("\\|");
String instanceFile = comparatorInstanceFiles[i];
// Here we use "false" as last parameter because otherwise it could be
// an infinite loop. We will call setConf() later.
RawComparator<?> comparator =
InstancesDistributor.loadInstance(conf, RawComparator.class, instanceFile, false);
if (ref[0].equals(COMMON)) {
setComparator(mrConfig.getCommonCriteria(), ref[1], comparator);
} else {
setComparator(
mrConfig.getSpecificOrderBys().get(new Integer(ref[0])), ref[1], comparator);
}
}
} catch (IOException e) {
throw new TupleMRException(e);
}
}
/** 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;
}