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.common.record;
  
  import java.io.IOException;
  
  /**
   * An abstraction between an underlying input stream and record iterators, a {@link LogInputStream} only returns
   * the batches at one level. For magic values 0 and 1, this means that it can either handle  iteration
   * at the top level of the log or deep iteration within the payload of a single message, but it does not attempt
   * to handle both. For magic value 2, this is only used for iterating over the top-level record batches (inner
   * records do not follow the {@link RecordBatch} interface).
   *
   * The generic typing allows for implementations which present only a view of the log entries, which enables more
   * efficient iteration when the record data is not actually needed. See for example
   * {@link FileLogInputStream.FileChannelRecordBatch} in which the record is not brought into memory until needed.
   *
   * @param <T> Type parameter of the log entry
   */
  interface LogInputStream<T extends RecordBatch> {
  
      /**
       * Get the next record batch from the underlying input stream.
       *
       * @return The next record batch or null if there is none
       * @throws IOException for any IO errors
       */
      T nextBatch() throws IOException;
  }
  