content: /*
   * 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.kafka.clients.consumer.internals;
  
  
  import org.apache.kafka.clients.consumer.ConsumerConfig;
  import org.apache.kafka.clients.consumer.ConsumerInterceptor;
  import org.apache.kafka.clients.consumer.ConsumerRecords;
  import org.apache.kafka.clients.consumer.OffsetAndMetadata;
  import org.apache.kafka.common.TopicPartition;
  import org.apache.kafka.common.internals.Plugin;
  import org.apache.kafka.common.metrics.Metrics;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.Closeable;
  import java.util.List;
  import java.util.Map;
  
  /**
   * A container that holds the list {@link org.apache.kafka.clients.consumer.ConsumerInterceptor}
   * and wraps calls to the chain of custom interceptors.
   */
  public class ConsumerInterceptors<K, V> implements Closeable {
      private static final Logger log = LoggerFactory.getLogger(ConsumerInterceptors.class);
      private final List<Plugin<ConsumerInterceptor<K, V>>> interceptorPlugins;
  
      public ConsumerInterceptors(List<ConsumerInterceptor<K, V>> interceptors, Metrics metrics) {
          this.interceptorPlugins = Plugin.wrapInstances(interceptors, metrics, ConsumerConfig.INTERCEPTOR_CLASSES_CONFIG);
      }
  
      /** Returns true if no interceptors are defined. All other methods will be no-ops in this case. */
      public boolean isEmpty() {
          return interceptorPlugins.isEmpty();
      }
  
      /**
       * This is called when the records are about to be returned to the user.
       * <p>
       * This method calls {@link ConsumerInterceptor#onConsume(ConsumerRecords)} for each
       * interceptor. Records returned from each interceptor get passed to onConsume() of the next interceptor
       * in the chain of interceptors.
       * <p>
       * This method does not throw exceptions. If any of the interceptors in the chain throws an exception,
       * it gets caught and logged, and next interceptor in the chain is called with 'records' returned by the
       * previous successful interceptor onConsume call.
       *
       * @param records records to be consumed by the client.
       * @return records that are either modified by interceptors or same as records passed to this method.
       */
      public ConsumerRecords<K, V> onConsume(ConsumerRecords<K, V> records) {
          ConsumerRecords<K, V> interceptRecords = records;
          for (Plugin<ConsumerInterceptor<K, V>> interceptorPlugin : this.interceptorPlugins) {
              try {
                  interceptRecords = interceptorPlugin.get().onConsume(interceptRecords);
              } catch (Exception e) {
                  // do not propagate interceptor exception, log and continue calling other interceptors
                  log.warn("Error executing interceptor onConsume callback", e);
              }
          }
          return interceptRecords;
      }
  
      /**
       * This is called when commit request returns successfully from the broker.
       * <p>
       * This method calls {@link ConsumerInterceptor#onCommit(Map)} method for each interceptor.
       * <p>
       * This method does not throw exceptions. Exceptions thrown by any of the interceptors in the chain are logged, but not propagated.
       *
       * @param offsets A map of offsets by partition with associated metadata
       */
      public void onCommit(Map<TopicPartition, OffsetAndMetadata> offsets) {
          for (Plugin<ConsumerInterceptor<K, V>> interceptorPlugin : this.interceptorPlugins) {
              try {
                  interceptorPlugin.get().onCommit(offsets);
              } catch (Exception e) {
                  // do not propagate interceptor exception, just log
                  log.warn("Error executing interceptor onCommit callback", e);
              }
          }
      }
  
      /**
       * Closes every interceptor in a container.
       */
      @Override
      public void close() {
          for (Plugin<ConsumerInterceptor<K, V>> interceptorPlugin : this.interceptorPlugins) {
              try {
                  interceptorPlugin.close();
              } catch (Exception e) {
                  log.error("Failed to close consumer interceptor ", e);
              }
          }
      }
  }
  