import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Utility class for parsing CSV text
 */
public final class KuromojiCSVUtil {
    private static final char QUOTE = '"';

    private static final char COMMA = ',';

    private static final Pattern QUOTE_REPLACE_PATTERN = Pattern.compile("^\"([^\"]+)\"$");

    private static final String ESCAPED_QUOTE = "\"\"";

    private KuromojiCSVUtil() {

import com.google.common.cache.CacheBuilder;

public class PopularWordHelper {
    private static final Logger logger = LogManager.getLogger(PopularWordHelper.class);

    protected static final char CACHE_KEY_SPLITTER = '\n';

    protected Cache<String, List<String>> cache;

    protected FessConfig fessConfig;

    @PostConstruct
    public void init() {
        if (logger.isDebugEnabled()) {

    private String unescape(final String s) {
        if (s.indexOf('\\') >= 0) {
            final StringBuilder sb = new StringBuilder();
            for (int i = 0; i < s.length(); i++) {
                final char ch = s.charAt(i);
                if (ch == '\\' && i < s.length() - 1) {
                    i++;
                    sb.append(s.charAt(i));
                } else {
                    sb.append(ch);

                .map(HttpServletRequest::getCharacterEncoding).orElse(Constants.UTF_8);
        final StringBuilder buf = new StringBuilder(url.length() + 100);
        for (final char c : url.toCharArray()) {
            if (CharUtil.isUrlChar(c)) {
                buf.append(c);
            } else {
                try {
                    buf.append(URLEncoder.encode(String.valueOf(c), enc));

    private String unescape(final String s) {
        if (s.indexOf('\\') >= 0) {
            final StringBuilder sb = new StringBuilder();
            for (int i = 0; i < s.length(); i++) {
                final char ch = s.charAt(i);
                if (ch == '\\' && i < s.length() - 1) {
                    i++;
                    sb.append(s.charAt(i));
                } else {
                    sb.append(ch);