public boolean readRecord(Record target, byte[] bytes, int offset, int numBytes) {
StringValue str = this.theString;
if (this.ascii) {
str.setValueAscii(bytes, offset, numBytes);
} else {
ByteBuffer byteWrapper = this.byteWrapper;
if (bytes != byteWrapper.array()) {
byteWrapper = ByteBuffer.wrap(bytes, 0, bytes.length);
this.byteWrapper = byteWrapper;
}
byteWrapper.limit(offset + numBytes);
byteWrapper.position(offset);
try {
CharBuffer result = this.decoder.decode(byteWrapper);
str.setValue(result);
} catch (CharacterCodingException e) {
byte[] copy = new byte[numBytes];
System.arraycopy(bytes, offset, copy, 0, numBytes);
LOG.warn("Line could not be encoded: " + Arrays.toString(copy), e);
return false;
}
}
target.clear();
target.setField(this.pos, str);
return true;
}
@Override
public int compare(DataInputView firstSource, DataInputView secondSource) throws IOException {
holder1.read(firstSource);
holder2.read(secondSource);
int comp = holder1.compareTo(holder2);
return ascendingComparison ? comp : -comp;
}
@Override
public Record readRecord(Record target, byte[] bytes, int offset, int numBytes) {
String lineStr = new String(bytes, offset, numBytes);
// replace reduce whitespaces and trim
lineStr = lineStr.replaceAll("\\s+", " ").trim();
// build whitespace tokenizer
StringTokenizer st = new StringTokenizer(lineStr, " ");
// line must have at least three elements
if (st.countTokens() < 3) {
return null;
}
String rdfSubj = st.nextToken();
String rdfPred = st.nextToken();
String rdfObj = st.nextToken();
// we only want foaf:knows predicates
if (!rdfPred.equals("<http://xmlns.com/foaf/0.1/knows>")) {
return null;
}
// build node pair from subject and object
fromNode.setValue(rdfSubj);
toNode.setValue(rdfObj);
target.setField(0, fromNode);
target.setField(1, toNode);
target.setField(2, pathLength);
target.setField(3, hopCnt);
target.setField(4, hopList);
return target;
}
@Override
public void join(Record rec1, Record rec2, Collector<Record> out) throws Exception {
// rec1 has matching start, rec2 matching end
// Therefore, rec2's end node and rec1's start node are identical
// First half of new path will be rec2, second half will be rec1
// Get from-node and to-node of new path
final StringValue fromNode = rec2.getField(0, StringValue.class);
final StringValue toNode = rec1.getField(1, StringValue.class);
// Check whether from-node = to-node to prevent circles!
if (fromNode.equals(toNode)) {
return;
}
// Create new path
outputRecord.setField(0, fromNode);
outputRecord.setField(1, toNode);
// Compute length of new path
length.setValue(
rec1.getField(2, IntValue.class).getValue()
+ rec2.getField(2, IntValue.class).getValue());
outputRecord.setField(2, length);
// compute hop count
int hops =
rec1.getField(3, IntValue.class).getValue()
+ 1
+ rec2.getField(3, IntValue.class).getValue();
hopCnt.setValue(hops);
outputRecord.setField(3, hopCnt);
// Concatenate hops lists and insert matching node
StringBuilder sb = new StringBuilder();
// first path
sb.append(rec2.getField(4, StringValue.class).getValue());
sb.append(" ");
// common node
sb.append(rec1.getField(0, StringValue.class).getValue());
// second path
sb.append(" ");
sb.append(rec1.getField(4, StringValue.class).getValue());
hopList.setValue(sb.toString().trim());
outputRecord.setField(4, hopList);
out.collect(outputRecord);
}
@Override
public int compare(DataInputView firstSource, DataInputView secondSource) throws IOException {
return StringValue.readString(firstSource).compareTo(StringValue.readString(secondSource));
}