code: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   *
   */
  
  package org.apache.skywalking.oap.server.core.analysis.worker;
  
  import org.apache.skywalking.oap.server.core.exporter.ExportEvent;
  import org.apache.skywalking.oap.server.core.exporter.ExporterModule;
  import org.apache.skywalking.oap.server.core.exporter.MetricValuesExportService;
  import org.apache.skywalking.oap.server.core.worker.AbstractWorker;
  import org.apache.skywalking.oap.server.library.module.ModuleDefineHolder;
  
  /**
   * A bridge worker. If the {@link ExporterModule} provider declared and provides a implementation of {@link
   * MetricValuesExportService}, forward the export data to it.
   */
  public class ExportMetricsWorker extends AbstractWorker<ExportEvent> {
      private MetricValuesExportService exportService;
  
      public ExportMetricsWorker(ModuleDefineHolder moduleDefineHolder) {
          super(moduleDefineHolder);
      }
  
      @Override
      public void in(ExportEvent event) {
          if (exportService != null || getModuleDefineHolder().has(ExporterModule.NAME)) {
              if (exportService == null) {
                  exportService = getModuleDefineHolder().find(ExporterModule.NAME)
                                                         .provider()
                                                         .getService(MetricValuesExportService.class);
              }
              if (exportService.isEnabled()) {
                  exportService.export(event);
              }
          }
      }
  }
  