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.trogdor.workload;
  
  import com.fasterxml.jackson.annotation.JsonCreator;
  import com.fasterxml.jackson.annotation.JsonProperty;
  
  import java.nio.ByteBuffer;
  import java.nio.ByteOrder;
  
  /**
   * A PayloadGenerator which generates a sequentially increasing payload.
   *
   * The generated number will wrap around to 0 after the maximum value is reached.
   * Payloads bigger than 8 bytes will always just be padded with zeros after byte 8.
   */
  public class SequentialPayloadGenerator implements PayloadGenerator {
      private final int size;
      private final long startOffset;
      private final ByteBuffer buf;
  
      @JsonCreator
      public SequentialPayloadGenerator(@JsonProperty("size") int size,
                                        @JsonProperty("offset") long startOffset) {
          this.size = size;
          this.startOffset = startOffset;
          this.buf = ByteBuffer.allocate(8);
          // Little-endian byte order allows us to support arbitrary lengths more easily,
          // since the first byte is always the lowest-order byte.
          this.buf.order(ByteOrder.LITTLE_ENDIAN);
      }
  
      @JsonProperty
      public int size() {
          return size;
      }
  
      @JsonProperty
      public long startOffset() {
          return startOffset;
      }
  
      @Override
      public synchronized byte[] generate(long position) {
          buf.clear();
          buf.putLong(position + startOffset);
          byte[] result = new byte[size];
          System.arraycopy(buf.array(), 0, result, 0, Math.min(buf.array().length, result.length));
          return result;
      }
  }
  