/*
    * ====================================================================
    * 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.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  package org.apache.http.conn.util;
  
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.net.URL;
  import java.util.Arrays;
  import java.util.List;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.http.Consts;
  import org.apache.http.annotation.Contract;
  import org.apache.http.annotation.ThreadingBehavior;
  import org.apache.http.util.Args;
  
  /**
   * {@link org.apache.http.conn.util.PublicSuffixMatcher} loader.
   *
   * @since 4.4
   */
  @Contract(threading = ThreadingBehavior.SAFE)
  public final class PublicSuffixMatcherLoader {
  
      private static PublicSuffixMatcher load(final InputStream in) throws IOException {
          final List<PublicSuffixList> lists = new PublicSuffixListParser().parseByType(
                  new InputStreamReader(in, Consts.UTF_8));
          return new PublicSuffixMatcher(lists);
      }
  
      public static PublicSuffixMatcher load(final URL url) throws IOException {
          Args.notNull(url, "URL");
          final InputStream in = url.openStream();
          try {
              return load(in);
          } finally {
              in.close();
          }
      }
  
      public static PublicSuffixMatcher load(final File file) throws IOException {
          Args.notNull(file, "File");
          final InputStream in = new FileInputStream(file);
          try {
              return load(in);
          } finally {
              in.close();
          }
      }
  
      private static volatile PublicSuffixMatcher DEFAULT_INSTANCE;
  
      public static PublicSuffixMatcher getDefault() {
          if (DEFAULT_INSTANCE == null) {
              synchronized (PublicSuffixMatcherLoader.class) {
                  if (DEFAULT_INSTANCE == null){
                      final URL url = PublicSuffixMatcherLoader.class.getResource(
                              "/mozilla/public-suffix-list.txt");
                      if (url != null) {
                          try {
                              DEFAULT_INSTANCE = load(url);
                          } catch (final IOException ex) {
                              // Should never happen
                              final Log log = LogFactory.getLog(PublicSuffixMatcherLoader.class);
                              if (log.isWarnEnabled()) {
                                  log.warn("Failure loading public suffix list from default resource", ex);
                              }
                          }
                      } else {
                          DEFAULT_INSTANCE = new PublicSuffixMatcher(DomainType.ICANN, Arrays.asList("com"), null);
                      }
                 }
             }
         }
         return DEFAULT_INSTANCE;
     }
 
 }