1   /**
    2    * Licensed under the Artistic License; you may not use this file
    3    * except in compliance with the License.
    4    * You may obtain a copy of the License at
    5    *
    6    *      http://displaytag.sourceforge.net/license.html
    7    *
    8    * THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
    9    * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
   10    * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
   11    */
   12   package org.displaytag.util;
   13   
   14   import java.util.ArrayList;
   15   import java.util.List;
   16   
   17   import org.apache.commons.lang.StringUtils;
   18   import org.apache.commons.logging.Log;
   19   import org.apache.commons.logging.LogFactory;
   20   import org.displaytag.properties.MediaTypeEnum;
   21   
   22   
   23   /**
   24    * This class provides services for configuring and determining the list of media types an instance of
   25    * <code>SupportsMedia</code> supports. (Background: ColumnTag, FooterTag and CaptionTag can be configured to support
   26    * a set of media types. This class factors the logic for setting and determining the media instances these objects
   27    * support)
   28    * @author Jorge L. Barroso
   29    * @version $Revision$ ($Author$)
   30    */
   31   public final class MediaUtil
   32   {
   33   
   34       /**
   35        * logger.
   36        */
   37       private static Log log = LogFactory.getLog(MediaUtil.class);
   38   
   39       /**
   40        * Don't instantiate MediaUtil.
   41        */
   42       private MediaUtil()
   43       {
   44       }
   45   
   46       /**
   47        * Defines a type of object that can support a list of media types.
   48        * @author Jorge L. Barroso
   49        * @version $Revision$ ($Author$)
   50        */
   51       public static interface SupportsMedia
   52       {
   53   
   54           /**
   55            * Configure the list of media types this object will support.
   56            * @param media The list of media types this object will support.
   57            */
   58           void setSupportedMedia(List media);
   59   
   60           /**
   61            * Obtain the list of media types this object supports.
   62            * @return The list of media types this object supports.
   63            */
   64           List getSupportedMedia();
   65       }
   66   
   67       /**
   68        * Configures the media supported by an object that implements <code>SupportsMedia</code>. (Background: factored
   69        * from ColumnTag)
   70        * @param mediaSupporter The <code>SupportsMedia</code> instance being configured to support a list of media.
   71        * @param media The media being configured on the given <code>SupportsMedia</code> instance.
   72        */
   73       public static void setMedia(SupportsMedia mediaSupporter, String media)
   74       {
   75           if (mediaSupporter == null)
   76           {
   77               return;
   78           }
   79   
   80           if (StringUtils.isBlank(media) || media.toLowerCase().indexOf("all") > -1)
   81           {
   82               mediaSupporter.setSupportedMedia(null);
   83               return;
   84           }
   85           List supportedMedia = new ArrayList();
   86           String[] values = StringUtils.split(media);
   87           for (int i = 0; i < values.length; i++)
   88           {
   89               String value = values[i];
   90               if (!StringUtils.isBlank(value))
   91               {
   92                   MediaTypeEnum type = MediaTypeEnum.fromName(value.toLowerCase());
   93                   if (type == null)
   94                   {
   95                       log.warn("Unrecognized value for attribute \"media\" value=\"" + value + "\"");
   96                   }
   97                   else
   98                   {
   99                       supportedMedia.add(type);
  100                   }
  101               }
  102           }
  103           mediaSupporter.setSupportedMedia(supportedMedia);
  104       }
  105   
  106       /**
  107        * Is this media supporter configured for the media type? (Background: Factored from ColumnTag)
  108        * @param mediaSupporter An object that supports various media.
  109        * @param mediaType The currentMedia type
  110        * @return true if the media supporter should be displayed for this request
  111        */
  112       public static boolean availableForMedia(SupportsMedia mediaSupporter, MediaTypeEnum mediaType)
  113       {
  114           if (mediaSupporter == null)
  115           {
  116               return false;
  117           }
  118   
  119           List supportedMedia = mediaSupporter.getSupportedMedia();
  120   
  121           if (supportedMedia == null)
  122           {
  123               return true;
  124           }
  125   
  126           return supportedMedia.contains(mediaType);
  127       }
  128   }