code: /*
   * 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.skywalking.oap.server.library.datacarrier.buffer;
  
  import java.util.List;
  import org.apache.skywalking.oap.server.library.datacarrier.common.AtomicRangeInteger;
  
  /**
   * Self implementation ring queue.
   */
  public class Buffer<T> implements QueueBuffer<T> {
      private final Object[] buffer;
      private BufferStrategy strategy;
      private AtomicRangeInteger index;
  
      Buffer(int bufferSize, BufferStrategy strategy) {
          buffer = new Object[bufferSize];
          this.strategy = strategy;
          index = new AtomicRangeInteger(0, bufferSize);
      }
  
      @Override
      public void setStrategy(BufferStrategy strategy) {
          this.strategy = strategy;
      }
  
      @Override
      public boolean save(T data) {
          int i = index.getAndIncrement();
          if (buffer[i] != null) {
              switch (strategy) {
                  case IF_POSSIBLE:
                      return false;
                  default:
              }
          }
          buffer[i] = data;
          return true;
      }
  
      @Override
      public int getBufferSize() {
          return buffer.length;
      }
  
      @Override
      public void obtain(List<T> consumeList) {
          this.obtain(consumeList, 0, buffer.length);
      }
  
      void obtain(List<T> consumeList, int start, int end) {
          for (int i = start; i < end; i++) {
              if (buffer[i] != null) {
                  consumeList.add((T) buffer[i]);
                  buffer[i] = null;
              }
          }
      }
  
  }
  