}

    @Test
    public void test_type_conversion_from_string() {
        Map<String, Object> doc = new HashMap<>();

        doc.put("intStr", "123");
        assertEquals(Integer.valueOf(123), DocumentUtil.getValue(doc, "intStr", Integer.class));

        doc.put("longStr", "123456789");
        assertEquals(Long.valueOf(123456789L), DocumentUtil.getValue(doc, "longStr", Long.class));

import com.fasterxml.jackson.core.type.TypeReference;
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.
 */