public void put(E e) throws InterruptedException {
    checkNotNull(e);
    Monitor monitor = this.monitor;
    monitor.enterWhen(notFull);
    try {
      insert(e);
    } finally {
      monitor.leave();
    }
  }

  @CanIgnoreReturnValue
  @Override
  public @Nullable E poll() {
    Monitor monitor = this.monitor;
    if (monitor.enterIf(notEmpty)) {
      try {
        return extract();

  @Override
  public <T> T[] toArray(T[] a) {
    Monitor monitor = this.monitor;
    monitor.enter();
    try {
      return q.toArray(a);
    } finally {
      monitor.leave();
    }
  }

  @CanIgnoreReturnValue // pushed down from class to method
  @Override
  public String toString() {
    Monitor monitor = this.monitor;
    monitor.enter();
    try {
      return q.toString();

{"index":{"_index":"fess_config.scheduled_job","_id":"ping_es"}}

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;

/**
 * Executable class for generating thumbnails for indexed documents.

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.

     * Get the value for the key 'crawler.system.monitor.interval'. <br>
     * The value is, e.g. 60 <br>
     * comment: Interval (seconds) for system monitor during crawling.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getCrawlerSystemMonitorInterval();

    /**
     * Get the value for the key 'crawler.system.monitor.interval' as {@link Integer}. <br>

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;

/**
 * Main executable class for running crawling operations in the Fess search engine.

import org.lastaflute.web.servlet.request.RequestManager;
import org.lastaflute.web.util.LaServletContextUtil;
import org.lastaflute.web.validation.ActionValidator;
import org.opensearch.monitor.os.OsProbe;

import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.ibm.icu.util.ULocale;