* It implements rank fusion techniques to combine results from different search engines
 * and provides a unified search interface.
 */
public class RankFusionProcessor implements AutoCloseable {

    private static final Logger logger = LogManager.getLogger(RankFusionProcessor.class);

    /** Thread-safe list of rank fusion searchers available for processing search requests */

        int pageSize = 100;
        int offset = 45;
        try (RankFusionProcessor rankFusionProcessor = new RankFusionProcessor()) {
            rankFusionProcessor.setSearcher(new TestMainSearcher(allRecordCount));
            rankFusionProcessor.register(new TestSubSearcher(10, 45, 45));
            rankFusionProcessor.init();

            if (rankFusionProcessor.search(query, new TestSearchRequestParams(0, pageSize, 0),

     */
    @Test
    public void test_emptySearcherList() throws Exception {
        try (RankFusionProcessor processor = new RankFusionProcessor()) {
            processor.init();

            // Should handle empty searcher list gracefully
            final List<Map<String, Object>> results = processor.search("*", new TestSearchRequestParams(0, 10, 0), OptionalThing.empty());

    /**
     * Test handling of searcher that throws RuntimeException.
     */
    @Test
    public void test_searcherThrowsRuntimeException() throws Exception {
        try (RankFusionProcessor processor = new RankFusionProcessor()) {
            processor.setSearcher(new TestSearcher(100));
            processor.register(new ExceptionThrowingSearcher(new RuntimeException("Test exception")));
            processor.init();

        final CountDownLatch endLatch = new CountDownLatch(numThreads);
        final AtomicInteger registeredCount = new AtomicInteger(0);

        try (RankFusionProcessor processor = new RankFusionProcessor()) {
            processor.setSearcher(new TestSearcher(100));
            processor.init();

            final ExecutorService executor = Executors.newFixedThreadPool(numThreads);
            try {

            final OptionalThing<FessUserBean> userBean) {
        final RankFusionProcessor rankFusionProcessor = ComponentUtil.getRankFusionProcessor();
        final List<Map<String, Object>> documentItems = rankFusionProcessor.search(query, params, userBean);
        if (documentItems instanceof final QueryResponseList queryResponseList) {

import org.codelibs.fess.query.QueryFieldConfig;
import org.codelibs.fess.query.QueryProcessor;
import org.codelibs.fess.query.parser.QueryParser;
import org.codelibs.fess.rank.fusion.RankFusionProcessor;
import org.codelibs.fess.script.ScriptEngineFactory;
import org.codelibs.fess.sso.SsoManager;
import org.codelibs.fess.thumbnail.ThumbnailManager;
import org.lastaflute.core.message.MessageManager;