/*
    * 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.myfaces.trinidad.util;
  
  import java.io.File;
  import java.io.IOException;
  
  import java.net.JarURLConnection;
  import java.net.URL;
  import java.net.URLConnection;
  
  public final class URLUtils
  {
    private URLUtils()
    {
    }
  
    public static long getLastModified(URL url) throws IOException
    {
      if ("file".equals(url.getProtocol()))
      {
        String externalForm = url.toExternalForm();
        // Remove the "file:"
        File file = new File(externalForm.substring(5));
  
        return file.lastModified();
      }
      else
      {
        return getLastModified(url.openConnection());
      }
    }
  
    public static long getLastModified(URLConnection connection) throws IOException
    {
      long modified;
      if (connection instanceof JarURLConnection)
      {
        // The following hack is required to work-around a JDK bug.
        // getLastModified() on a JAR entry URL delegates to the actual JAR file
        // rather than the JAR entry.
        // This opens internally, and does not close, an input stream to the JAR
        // file.
        // In turn, you cannot close it by yourself, because it's internal.
        // The work-around is to get the modification date of the JAR file
        // manually,
        // and then close that connection again.
  
        URL jarFileUrl = ((JarURLConnection) connection).getJarFileURL();
        URLConnection jarFileConnection = jarFileUrl.openConnection();
  
        try
        {
          modified = jarFileConnection.getLastModified();
        }
        finally
        {
          try
          {
            jarFileConnection.getInputStream().close();
          }
          catch (Exception exception)
          {
            // Ignored
          }
        }
      }
      else
      {
        modified = connection.getLastModified();
      }
  
      return modified;
    }
  }