/** encodes an entry (bytes+(contexts)+(payload)+weight) to the provided writer */
protected void encode(
ByteSequencesWriter writer,
ByteArrayDataOutput output,
byte[] buffer,
BytesRef spare,
BytesRef payload,
Set<BytesRef> contexts,
long weight)
throws IOException {
int requiredLength = spare.length + 8 + ((hasPayloads) ? 2 + payload.length : 0);
if (hasContexts) {
for (BytesRef ctx : contexts) {
requiredLength += 2 + ctx.length;
}
requiredLength += 2; // for length of contexts
}
if (requiredLength >= buffer.length) {
buffer = ArrayUtil.grow(buffer, requiredLength);
}
output.reset(buffer);
output.writeBytes(spare.bytes, spare.offset, spare.length);
if (hasContexts) {
for (BytesRef ctx : contexts) {
output.writeBytes(ctx.bytes, ctx.offset, ctx.length);
output.writeShort((short) ctx.length);
}
output.writeShort((short) contexts.size());
}
if (hasPayloads) {
output.writeBytes(payload.bytes, payload.offset, payload.length);
output.writeShort((short) payload.length);
}
output.writeLong(weight);
writer.write(buffer, 0, output.getPosition());
}
@Override
protected void encode(
ByteSequencesWriter writer,
ByteArrayDataOutput output,
byte[] buffer,
BytesRef spare,
long weight)
throws IOException {
if (spare.length + 5 >= buffer.length) {
buffer = ArrayUtil.grow(buffer, spare.length + 5);
}
output.reset(buffer);
output.writeBytes(spare.bytes, spare.offset, spare.length);
output.writeByte((byte) 0); // separator: not used, just for sort order
output.writeInt(encodeWeight(weight));
writer.write(buffer, 0, output.getPosition());
}
@Override
public void build(TermFreqIterator tfit) throws IOException {
if (tfit instanceof TermFreqPayloadIterator) {
throw new IllegalArgumentException("this suggester doesn't support payloads");
}
File tempInput =
File.createTempFile(
FSTCompletionLookup.class.getSimpleName(), ".input", Sort.defaultTempDir());
File tempSorted =
File.createTempFile(
FSTCompletionLookup.class.getSimpleName(), ".sorted", Sort.defaultTempDir());
Sort.ByteSequencesWriter writer = new Sort.ByteSequencesWriter(tempInput);
Sort.ByteSequencesReader reader = null;
ExternalRefSorter sorter = null;
// Push floats up front before sequences to sort them. For now, assume they are non-negative.
// If negative floats are allowed some trickery needs to be done to find their byte order.
boolean success = false;
try {
byte[] buffer = new byte[0];
ByteArrayDataOutput output = new ByteArrayDataOutput(buffer);
BytesRef spare;
while ((spare = tfit.next()) != null) {
if (spare.length + 4 >= buffer.length) {
buffer = ArrayUtil.grow(buffer, spare.length + 4);
}
output.reset(buffer);
output.writeInt(encodeWeight(tfit.weight()));
output.writeBytes(spare.bytes, spare.offset, spare.length);
writer.write(buffer, 0, output.getPosition());
}
writer.close();
// We don't know the distribution of scores and we need to bucket them, so we'll sort
// and divide into equal buckets.
SortInfo info = new Sort().sort(tempInput, tempSorted);
tempInput.delete();
FSTCompletionBuilder builder =
new FSTCompletionBuilder(
buckets, sorter = new ExternalRefSorter(new Sort()), sharedTailLength);
final int inputLines = info.lines;
reader = new Sort.ByteSequencesReader(tempSorted);
long line = 0;
int previousBucket = 0;
int previousScore = 0;
ByteArrayDataInput input = new ByteArrayDataInput();
BytesRef tmp1 = new BytesRef();
BytesRef tmp2 = new BytesRef();
while (reader.read(tmp1)) {
input.reset(tmp1.bytes);
int currentScore = input.readInt();
int bucket;
if (line > 0 && currentScore == previousScore) {
bucket = previousBucket;
} else {
bucket = (int) (line * buckets / inputLines);
}
previousScore = currentScore;
previousBucket = bucket;
// Only append the input, discard the weight.
tmp2.bytes = tmp1.bytes;
tmp2.offset = input.getPosition();
tmp2.length = tmp1.length - input.getPosition();
builder.add(tmp2, bucket);
line++;
}
// The two FSTCompletions share the same automaton.
this.higherWeightsCompletion = builder.build();
this.normalCompletion =
new FSTCompletion(higherWeightsCompletion.getFST(), false, exactMatchFirst);
success = true;
} finally {
if (success) IOUtils.close(reader, writer, sorter);
else IOUtils.closeWhileHandlingException(reader, writer, sorter);
tempInput.delete();
tempSorted.delete();
}
}
