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.kstream.ForeachAction;
  import org.apache.kafka.streams.kstream.KeyValueMapper;
  
  import java.io.OutputStream;
  import java.io.OutputStreamWriter;
  import java.io.PrintWriter;
  import java.nio.charset.StandardCharsets;
  
  public class PrintForeachAction<K, V> implements ForeachAction<K, V> {
  
      private final String label;
      private final PrintWriter printWriter;
      private final boolean closable;
      private final KeyValueMapper<? super K, ? super V, String> mapper;
  
      /**
       * Print customized output with given writer. The {@link OutputStream} can be {@link System#out} or the others.
       *
       * @param outputStream The output stream to write to.
       * @param mapper The mapper which can allow user to customize output will be printed.
       * @param label The given name will be printed.
       */
      PrintForeachAction(final OutputStream outputStream,
                         final KeyValueMapper<? super K, ? super V, String> mapper,
                         final String label) {
          this.printWriter = new PrintWriter(new OutputStreamWriter(outputStream, StandardCharsets.UTF_8));
          this.closable = outputStream != System.out && outputStream != System.err;
          this.mapper = mapper;
          this.label = label;
      }
  
      @Override
      public void apply(final K key, final V value) {
          final String data = String.format("[%s]: %s", label, mapper.apply(key, value));
          printWriter.println(data);
          if (!closable) {
              printWriter.flush();
          }
      }
  
      public void close() {
          if (closable) {
              printWriter.close();
          } else {
              printWriter.flush();
          }
      }
  
  }
  