/*
    * 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 javax.net.ssl.SSLEngine;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Set;
  
  /**
   * This class will filter all requested ciphers out that are not supported by the current {@link SSLEngine}.
   */
  public final class SupportedCipherSuiteFilter implements CipherSuiteFilter {
      public static final SupportedCipherSuiteFilter INSTANCE = new SupportedCipherSuiteFilter();
  
      private SupportedCipherSuiteFilter() { }
  
      @Override
      public String[] filterCipherSuites(Iterable<String> ciphers, List<String> defaultCiphers,
              Set<String> supportedCiphers) {
          if (defaultCiphers == null) {
              throw new NullPointerException("defaultCiphers");
          }
          if (supportedCiphers == null) {
              throw new NullPointerException("supportedCiphers");
          }
  
          final List<String> newCiphers;
          if (ciphers == null) {
              newCiphers = new ArrayList<String>(defaultCiphers.size());
              ciphers = defaultCiphers;
          } else {
              newCiphers = new ArrayList<String>(supportedCiphers.size());
          }
          for (String c : ciphers) {
              if (c == null) {
                  break;
              }
              if (supportedCiphers.contains(c)) {
                  newCiphers.add(c);
              }
          }
          return newCiphers.toArray(new String[newCiphers.size()]);
      }
  
  }