/**
* Only read the columns that were requested in the constructor.<br>
*
* @param struct ColumnarStruct
* @param path Path
* @return Tuple
* @throws IOException
*/
private Tuple readColumnarTuple(ColumnarStruct struct, Path path) throws IOException {
int[] columnIndexes = getRequiredColumns();
// the partition keys if any will already be in the UDFContext here.
String[] partitionKeys = getPartitionKeys(null, null);
// only if the path has changed should be run the
if (currentPath == null || !currentPath.equals(path)) {
currentPathPartitionKeyMap =
(partitionKeys == null)
? null
: pathPartitionerHelper.getPathPartitionKeyValues(path.toString());
currentPath = path;
}
// if the partitionColumns is null this value will stop the for loop
// below from trynig to add any partition columns
// that do not exist
int partitionColumnStartIndex = Integer.MAX_VALUE;
if (!(partitionColumns == null || partitionColumns.size() == 0)) {
// partition columns are always appended to the schema fields.
partitionColumnStartIndex = pigSchema.getFields().length;
}
// create tuple with determined previous size
Tuple t = tupleFactory.newTuple(columnIndexes.length);
// read in all columns
for (int i = 0; i < columnIndexes.length; i++) {
int columnIndex = columnIndexes[i];
if (columnIndex < partitionColumnStartIndex) {
Object obj = struct.getField(columnIndex);
Object pigType = HiveRCSchemaUtil.extractPigTypeFromHiveType(obj);
t.set(i, pigType);
} else {
// read the partition columns
// will only be executed if partitionColumns is not null
String key = partitionKeys[columnIndex - partitionColumnStartIndex];
Object value = currentPathPartitionKeyMap.get(key);
t.set(i, value);
}
}
return t;
}
/**
* Reads the partition columns
*
* @param location
* @param job
* @return
*/
private Set<String> getPartitionColumns(String location, Job job) {
if (partitionColumns == null) {
// read the partition columns from the UDF Context first.
// if not in the UDF context then read it using the PathPartitioner.
Properties properties = getUDFContext();
if (properties == null) properties = new Properties();
String partitionColumnStr = properties.getProperty(PathPartitionHelper.PARTITION_COLUMNS);
if (partitionColumnStr == null && !(location == null || job == null)) {
// if it hasn't been written yet.
Set<String> partitionColumnSet;
try {
partitionColumnSet =
pathPartitionerHelper.getPartitionKeys(location, job.getConfiguration());
} catch (IOException e) {
RuntimeException rte = new RuntimeException(e);
rte.setStackTrace(e.getStackTrace());
throw rte;
}
if (partitionColumnSet != null) {
StringBuilder buff = new StringBuilder();
int i = 0;
for (String column : partitionColumnSet) {
if (i++ != 0) {
buff.append(',');
}
buff.append(column);
}
String buffStr = buff.toString().trim();
if (buffStr.length() > 0) {
properties.setProperty(PathPartitionHelper.PARTITION_COLUMNS, buff.toString());
}
partitionColumns = partitionColumnSet;
}
} else {
// the partition columns has been set already in the UDF Context
if (partitionColumnStr != null) {
String split[] = partitionColumnStr.split(",");
partitionColumns = new LinkedHashSet<String>();
if (split.length > 0) {
for (String splitItem : split) {
partitionColumns.add(splitItem);
}
}
}
}
}
return partitionColumns;
}
