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.streams.kstream.internals;
  
  import org.apache.kafka.streams.KeyValue;
  import org.apache.kafka.streams.kstream.KeyValueMapper;
  import org.apache.kafka.streams.processor.api.ContextualProcessor;
  import org.apache.kafka.streams.processor.api.Processor;
  import org.apache.kafka.streams.processor.api.ProcessorSupplier;
  import org.apache.kafka.streams.processor.api.Record;
  
  import java.util.Objects;
  
  class KStreamMap<KIn, VIn, KOut, VOut> implements ProcessorSupplier<KIn, VIn, KOut, VOut> {
  
      private final KeyValueMapper<? super KIn, ? super VIn, ? extends KeyValue<? extends KOut, ? extends VOut>> mapper;
  
      public KStreamMap(final KeyValueMapper<? super KIn, ? super VIn, ? extends KeyValue<? extends KOut, ? extends VOut>> mapper) {
          this.mapper = mapper;
      }
  
      @Override
      public Processor<KIn, VIn, KOut, VOut> get() {
          return new KStreamMapProcessor();
      }
  
      private class KStreamMapProcessor extends ContextualProcessor<KIn, VIn, KOut, VOut> {
  
          @Override
          public void process(final Record<KIn, VIn> record) {
              final KeyValue<? extends KOut, ? extends VOut> newPair =
                  mapper.apply(record.key(), record.value());
              Objects.requireNonNull(newPair, "The provided KeyValueMapper returned null which is not allowed.");
              context().forward(record.withKey(newPair.key).withValue(newPair.value));
          }
      }
  }
  