public static final Storage get(String type) {
// these are built-in storage type
if (type.equalsIgnoreCase("AVRO")) return new AvroStorage();
if (type.equalsIgnoreCase("TEXT")) return new TextStorage();
if (type.equalsIgnoreCase("RUBIX")) return new RubixStorage();
if (type.equalsIgnoreCase("SHUFFLE")) return new ShuffleStorage();
if (type.equalsIgnoreCase("VIRTUAL")) return new VirtualStorage();
// if not built-in, it may be a path to external class
try {
Class<? extends Storage> cls = ClassCache.forName(type).asSubclass(Storage.class);
return cls.newInstance();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
return null;
}
@SuppressWarnings("unchecked")
public List<KeyData<K>> getKeyData() throws IOException, ClassNotFoundException {
if (keyData != null) return keyData;
final FileSystem fs = FileSystem.get(conf);
keyData = new ArrayList<KeyData<K>>();
final long filesize = fs.getFileStatus(path).getLen();
FSDataInputStream in = fs.open(path);
/* The last long in the file is the start position of the trailer section */
in.seek(filesize - 8);
long metaDataStartPos = in.readLong();
in.seek(metaDataStartPos);
ObjectMapper mapper = new ObjectMapper();
metadataJson = mapper.readValue(in.readUTF(), JsonNode.class);
int keySectionSize = in.readInt();
// load the key section
byte[] keySection = new byte[keySectionSize];
in.seek(filesize - keySectionSize - 8);
in.read(keySection, 0, keySectionSize);
in.close();
ByteArrayInputStream bis = new ByteArrayInputStream(keySection);
DataInput dataInput = new DataInputStream(bis);
int numberOfBlocks = metadataJson.get("numberOfBlocks").getIntValue();
// load the key section
keyClass = (Class<K>) ClassCache.forName(JsonUtils.getText(metadataJson, "keyClass"));
valueClass = (Class<V>) ClassCache.forName(JsonUtils.getText(metadataJson, "valueClass"));
SerializationFactory serializationFactory = new SerializationFactory(conf);
Deserializer<K> deserializer = serializationFactory.getDeserializer(keyClass);
deserializer.open(bis);
while (bis.available() > 0 && numberOfBlocks > 0) {
K key = deserializer.deserialize(null);
long offset = dataInput.readLong();
long blockId = dataInput.readLong();
long numRecords = dataInput.readLong();
keyData.add(new KeyData<K>(key, offset, 0, numRecords, blockId));
numberOfBlocks--;
}
// Assign length to each keydata entry
int numEntries = keyData.size();
for (int i = 1; i < numEntries; i++) {
KeyData<K> prev = keyData.get(i - 1);
KeyData<K> current = keyData.get(i);
prev.setLength(current.getOffset() - prev.getOffset());
}
if (numEntries > 0) {
KeyData<K> last = keyData.get(numEntries - 1);
last.setLength(metaDataStartPos - last.offset);
}
return keyData;
}