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 com.datastax.oss.driver.internal.core.util;
  
  import edu.umd.cs.findbugs.annotations.NonNull;
  import java.nio.ByteBuffer;
  
  public class RoutingKey {
  
    /** Assembles multiple routing key components into a single buffer. */
    @NonNull
    public static ByteBuffer compose(@NonNull ByteBuffer... components) {
      if (components.length == 1) return components[0];
  
      int totalLength = 0;
      for (ByteBuffer bb : components) totalLength += 2 + bb.remaining() + 1;
  
      ByteBuffer out = ByteBuffer.allocate(totalLength);
      for (ByteBuffer buffer : components) {
        ByteBuffer bb = buffer.duplicate();
        putShortLength(out, bb.remaining());
        out.put(bb);
        out.put((byte) 0);
      }
      out.flip();
      return out;
    }
  
    private static void putShortLength(ByteBuffer bb, int length) {
      bb.put((byte) ((length >> 8) & 0xFF));
      bb.put((byte) (length & 0xFF));
    }
  }
  