import org.lastaflute.web.util.LaRequestUtil;
import org.opensearch.action.search.SearchRequestBuilder;
import org.opensearch.action.search.SearchResponse;
import org.opensearch.common.document.DocumentField;
import org.opensearch.search.SearchHit;
import org.opensearch.search.SearchHits;
import org.opensearch.search.aggregations.Aggregations;
import org.opensearch.search.fetch.subphase.highlight.HighlightField;

/**

- [Customization Guide](https://github.com/codelibs/fess-site-search)

---

### Elasticsearch / OpenSearch

If you're migrating from a standalone Elasticsearch or OpenSearch deployment:

#### Document Migration

**Step 1: Export from Source**

Export documents from your existing Elasticsearch/OpenSearch cluster:

```bash
# Using elasticdump
elasticdump \
  --input=http://old-es-server:9200/my-index \

import org.junit.jupiter.api.Test;
import org.lastaflute.di.exception.IORuntimeException;
import org.opensearch.common.xcontent.XContentType;
import org.opensearch.core.xcontent.MediaType;
import org.opensearch.core.xcontent.ToXContent;
import org.opensearch.core.xcontent.XContentBuilder;

public class SearchEngineUtilTest extends UnitFessTestCase {

    @Test

indexer.language.fields=content,important_content,title
```

## Optional: Search Analysis Support

If your language requires special text analysis (stemming, stop words, etc.), you may need to configure OpenSearch analyzers.

### 1. Update OpenSearch Index Template

Edit `src/main/resources/fess_indices/fess.json` to add language-specific analyzers.

**Example for Swedish:**
```json
{
  "analysis": {
    "filter": {

import org.lastaflute.web.util.LaRequestUtil;
import org.opensearch.action.search.SearchRequestBuilder;
import org.opensearch.index.query.BoolQueryBuilder;
import org.opensearch.index.query.QueryBuilder;
import org.opensearch.index.query.QueryBuilders;
import org.opensearch.index.query.functionscore.FunctionScoreQueryBuilder.FilterFunctionBuilder;
import org.opensearch.index.query.functionscore.ScoreFunctionBuilder;

                switch (propertyKey) {
                case "domain.title":
                    return "Test Fess";
                case "search_engine.type":
                    return "opensearch";
                case "test.property":
                    return "config-value";
                case "filter.null":
                    // This would be filtered to null by PropertyFilter in real scenario

import org.codelibs.fess.app.web.base.FessAdminAction;
import org.codelibs.fess.helper.CoordinatorHelper;
import org.codelibs.fess.mylasta.direction.FessConfig.SimpleImpl;
import org.codelibs.fess.opensearch.client.SearchEngineClient;
import org.codelibs.fess.util.ComponentUtil;
import org.codelibs.fess.util.IpAddressUtil;
import org.codelibs.fess.util.SearchEngineUtil;
import org.lastaflute.web.Execute;

import org.lastaflute.di.core.external.GenericExternalContextComponentDefRegister;
import org.lastaflute.di.core.factory.SingletonLaContainerFactory;
import org.opensearch.monitor.jvm.JvmInfo;
import org.opensearch.monitor.os.OsProbe;
import org.opensearch.monitor.process.ProcessProbe;

import jakarta.annotation.Resource;

/**
 * This class is a command-line application for creating and managing the suggest index.

     */
    protected ResourceUtil() {
        // nothing
    }

    /**
     * Gets the HTTP URL for the OpenSearch (Fesen) server.
     * First checks for a system-configured search engine address,
     * then falls back to the URL configured in FessConfig.
     *
     * @return the HTTP URL for the OpenSearch server
     */
    public static String getFesenHttpUrl() {

import com.fasterxml.jackson.databind.ObjectMapper;

import jakarta.annotation.PostConstruct;
import jakarta.annotation.PreDestroy;

/**
 * Helper for inter-instance coordination via OpenSearch.
 * Provides heartbeat registration, distributed operation locking, and event notification
 * to prevent concurrent execution of maintenance operations across multiple Fess instances.
 */
public class CoordinatorHelper {