import org.apache.lucene.util.fst.FST; //导入方法依赖的package包/类

/**

*

* @param inputStream the input stream

* @param outputStream the output stream

* @throws IOException if compilation fails

*/

public void compile(InputStream inputStream, OutputStream outputStream) throws IOException {

final HashSet words = new HashSet<>();

BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, StandardCharsets.UTF_8));

String line;

String last = null;

StringBuilder stringBuilder = new StringBuilder();

while ((line = reader.readLine()) != null) {

if (line.indexOf('#') >= 0) {

continue;

}

line = pattern.split(line)[0].trim();

line = line.toLowerCase();

if (line.equals(last)) {

continue;

}

last = line;

/*

* Add the word to the hash set in left-to-right characters order and reversed

* for easier matching later on.

*/

stringBuilder.setLength(0);

stringBuilder.append(line);

final int len = stringBuilder.length();

stringBuilder.append('>');

words.add(new BytesRef(stringBuilder));

stringBuilder.setLength(len);

stringBuilder.reverse().append('

words.add(new BytesRef(stringBuilder));

}

reader.close();

final BytesRef [] all = new BytesRef[words.size()];

words.toArray(all);

Arrays.sort(all, BytesRef::compareTo);

final Object nothing = NoOutputs.getSingleton().getNoOutput();

final Builder builder = new Builder<>(INPUT_TYPE.BYTE4, NoOutputs.getSingleton());

final IntsRefBuilder intsRef = new IntsRefBuilder();

for (BytesRef bytesRef : all) {

intsRef.clear();

intsRef.copyUTF8Bytes(bytesRef);

builder.add(intsRef.get(), nothing);

}

final FST fst = builder.finish();

try (final OutputStreamDataOutput out = new OutputStreamDataOutput(outputStream)) {

fst.save(out);

}

}