/*

  * 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.shared.resource;

 import java.io.File;

 import java.io.IOException;

 import java.net.JarURLConnection;

 import java.net.URL;

 import java.net.URLConnection;

 import java.text.ParseException;

 import java.text.SimpleDateFormat;

 import java.util.Date;

 import java.util.Locale;

 import java.util.TimeZone;

 public class ResourceLoaderUtils

 {

     // TODO: In tomcat and jetty it is implemented a Flyweight pattern when converting

     // date headers. For now it is better keep this stuff simple.

     private static final String HTTP_RESPONSE_DATE_HEADER =

         "EEE, dd MMM yyyy HH:mm:ss zzz";

     private static final String[] HTTP_REQUEST_DATE_HEADER = {

             "EEE, dd MMM yyyy HH:mm:ss zzz", "EEEEEE, dd-MMM-yy HH:mm:ss zzz",

             "EEE MMMM d HH:mm:ss yyyy" };

     private static final TimeZone GMT = TimeZone.getTimeZone("GMT");

     public static String formatDateHeader(long value)

     {

         SimpleDateFormat format = new SimpleDateFormat(

                 HTTP_RESPONSE_DATE_HEADER,

                 Locale.US);

         format.setTimeZone(GMT);

         return format.format(new Date(value));

     }

     public static Long parseDateHeader(String value)

     {

         Date date = null;

         for (int i = 0; (date == null) && (i < HTTP_REQUEST_DATE_HEADER.length); i++)

         {

             try

             {

                 SimpleDateFormat format = new SimpleDateFormat(

                         HTTP_REQUEST_DATE_HEADER[i], Locale.US);

                 format.setTimeZone(GMT);

                 date = format.parse(value);

             }

             catch (ParseException e)

             {

                 // all fine

             }

         }

         if (date == null)

         {

             return null;

         }

         return Long.valueOf(date.getTime());

     }

     //Taken from trinidad URLUtils

     public static long getResourceLastModified(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 getResourceLastModified(url.openConnection());

         }

     }

     //Taken from trinidad URLUtils

     public static long getResourceLastModified(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;

     }

 }