簡単な解決策として、ドキュメントを小文字化し、空白でトークン化し、各用語の連続する文字を折りたたむことができます。
import java.util.Map;
import java.util.Scanner;
import java.util.Set;
import java.util.TreeMap;
import java.util.TreeSet;
import java.util.stream.Collectors;
public class CollapseConsecutiveCharsDemo {
public static String collapse(final String term) {
final StringBuilder buffer = new StringBuilder();
if (!term.isEmpty()) {
char prev = term.charAt(0);
buffer.append(prev);
for (int i = 1; i < term.length(); i += 1) {
final char curr = term.charAt(i);
if (curr != prev) {
buffer.append(curr);
prev = curr;
}
}
}
return buffer.toString();
}
public static void main(final String... documents) {
final Map<String, Set<String>> termVariations = new TreeMap<>();
for (final String document : documents) {
final Scanner scanner = new Scanner(document.toLowerCase());
while (scanner.hasNext()) {
final String expandedTerm = scanner.next();
final String collapsedTerm = collapse(expandedTerm);
Set<String> variations = termVariations.get(collapsedTerm);
if (null == variations) {
variations = new TreeSet<String>();
termVariations.put(collapsedTerm, variations);
}
variations.add(expandedTerm);
}
}
for (final Map.Entry<String, Set<String>> entry : termVariations.entrySet()) {
final String term = entry.getKey();
final Set<String> variations = entry.getValue();
System.out.printf("variations(\"%s\") = {%s}%n",
term,
variations.stream()
.map((variation) -> String.format("\"%s\"", variation))
.collect(Collectors.joining(", ")));
}
}
}
実行例:
% java CollapseConsecutiveCharsDemo "We had an awwweesssommmeeee dinner at sea resort" "We had an awesomeeee dinner at sea resort" "We had an awwesooomee dinner at sea resort"
variations("an") = {"an"}
variations("at") = {"at"}
variations("awesome") = {"awesomeeee", "awwesooomee", "awwweesssommmeeee"}
variations("diner") = {"dinner"}
variations("had") = {"had"}
variations("resort") = {"resort"}
variations("sea") = {"sea"}
variations("we") = {"we"}
より精巧なソリューションとして、句読点を正しく処理するStanford CoreNLP tokenizerを使用してドキュメントをトークン化し、 libblevenshteinなどのスペル修正と組み合わせることができます。