/*
    * Copyright 2014 The Netty Project
    *
    * The Netty Project 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 io.netty.handler.ssl;
  
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * Utility class for application protocol common operations.
   */
  final class ApplicationProtocolUtil {
      private static final int DEFAULT_LIST_SIZE = 2;
  
      private ApplicationProtocolUtil() {
      }
  
      static List<String> toList(Iterable<String> protocols) {
          return toList(DEFAULT_LIST_SIZE, protocols);
      }
  
      static List<String> toList(int initialListSize, Iterable<String> protocols) {
          if (protocols == null) {
              return null;
          }
  
          List<String> result = new ArrayList<String>(initialListSize);
          for (String p : protocols) {
              if (p == null || p.isEmpty()) {
                  throw new IllegalArgumentException("protocol cannot be null or empty");
              }
              result.add(p);
          }
  
          if (result.isEmpty()) {
              throw new IllegalArgumentException("protocols cannot empty");
          }
  
          return result;
      }
  
      static List<String> toList(String... protocols) {
          return toList(DEFAULT_LIST_SIZE, protocols);
      }
  
      static List<String> toList(int initialListSize, String... protocols) {
          if (protocols == null) {
              return null;
          }
  
          List<String> result = new ArrayList<String>(initialListSize);
          for (String p : protocols) {
              if (p == null || p.isEmpty()) {
                  throw new IllegalArgumentException("protocol cannot be null or empty");
              }
              result.add(p);
          }
  
          if (result.isEmpty()) {
              throw new IllegalArgumentException("protocols cannot empty");
          }
  
          return result;
      }
  }