src/main/java/net/pterodactylus/sone/notify/ListNotificationFilters.java

   1 /*
   2  * Sone - ListNotificationFilters.java - Copyright © 2010–2012 David Roden
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 package net.pterodactylus.sone.notify;
  19
  20 import java.util.ArrayList;
  21 import java.util.Collection;
  22 import java.util.List;
  23
  24 import net.pterodactylus.sone.data.Post;
  25 import net.pterodactylus.sone.data.PostReply;
  26 import net.pterodactylus.sone.data.Reply;
  27 import net.pterodactylus.sone.data.Sone;
  28 import net.pterodactylus.sone.freenet.wot.OwnIdentity;
  29 import net.pterodactylus.sone.freenet.wot.Trust;
  30 import net.pterodactylus.util.notify.Notification;
  31 import net.pterodactylus.util.validation.Validation;
  32
  33 /**
  34  * Filter for {@link ListNotification}s.
  35  *
  36  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  37  */
  38 public class ListNotificationFilters {
  39
  40         /**
  41          * Filters new-post and new-reply notifications in the given list of
  42          * notifications. If {@code currentSone} is <code>null</code>, new-post and
  43          * new-reply notifications are removed completely. If {@code currentSone} is
  44          * not {@code null}, only posts that are posted by a friend Sone or the Sone
  45          * itself, and replies that are replies to posts of friend Sones or the Sone
  46          * itself will be retained in the notifications.
  47          *
  48          * @param notifications
  49          *            The notifications to filter
  50          * @param currentSone
  51          *            The current Sone, or {@code null} if not logged in
  52          * @return The filtered notifications
  53          */
  54         @SuppressWarnings("unchecked")
  55         public static List<Notification> filterNotifications(Collection<? extends Notification> notifications, Sone currentSone) {
  56                 List<Notification> filteredNotifications = new ArrayList<Notification>();
  57                 for (Notification notification : notifications) {
  58                         if (notification.getId().equals("new-sone-notification")) {
  59                                 if ((currentSone != null) && (!currentSone.getOptions().getBooleanOption("ShowNotification/NewSones").get())) {
  60                                         continue;
  61                                 }
  62                                 filteredNotifications.add(notification);
  63                         } else if (notification.getId().equals("new-post-notification")) {
  64                                 if ((currentSone != null) && (!currentSone.getOptions().getBooleanOption("ShowNotification/NewPosts").get())) {
  65                                         continue;
  66                                 }
  67                                 ListNotification<Post> filteredNotification = filterNewPostNotification((ListNotification<Post>) notification, currentSone, true);
  68                                 if (filteredNotification != null) {
  69                                         filteredNotifications.add(filteredNotification);
  70                                 }
  71                         } else if (notification.getId().equals("new-reply-notification")) {
  72                                 if ((currentSone != null) && (!currentSone.getOptions().getBooleanOption("ShowNotification/NewReplies").get())) {
  73                                         continue;
  74                                 }
  75                                 ListNotification<PostReply> filteredNotification = filterNewReplyNotification((ListNotification<PostReply>) notification, currentSone);
  76                                 if (filteredNotification != null) {
  77                                         filteredNotifications.add(filteredNotification);
  78                                 }
  79                         } else if (notification.getId().equals("mention-notification")) {
  80                                 ListNotification<Post> filteredNotification = filterNewPostNotification((ListNotification<Post>) notification, null, false);
  81                                 if (filteredNotification != null) {
  82                                         filteredNotifications.add(filteredNotification);
  83                                 }
  84                         } else {
  85                                 filteredNotifications.add(notification);
  86                         }
  87                 }
  88                 return filteredNotifications;
  89         }
  90
  91         /**
  92          * Filters the new posts of the given notification. If {@code currentSone}
  93          * is {@code null} and {@code soneRequired} is {@code true}, {@code null} is
  94          * returned and the notification is subsequently removed. Otherwise only
  95          * posts that are posted by friend Sones of the given Sone are retained; all
  96          * other posts are removed.
  97          *
  98          * @param newPostNotification
  99          *            The new-post notification
 100          * @param currentSone
 101          *            The current Sone, or {@code null} if not logged in
 102          * @param soneRequired
 103          *            Whether a non-{@code null} Sone in {@code currentSone} is
 104          *            required
 105          * @return The filtered new-post notification, or {@code null} if the
 106          *         notification should be removed
 107          */
 108         public static ListNotification<Post> filterNewPostNotification(ListNotification<Post> newPostNotification, Sone currentSone, boolean soneRequired) {
 109                 if (soneRequired && (currentSone == null)) {
 110                         return null;
 111                 }
 112                 List<Post> newPosts = new ArrayList<Post>();
 113                 for (Post post : newPostNotification.getElements()) {
 114                         if (isPostVisible(currentSone, post)) {
 115                                 newPosts.add(post);
 116                         }
 117                 }
 118                 if (newPosts.isEmpty()) {
 119                         return null;
 120                 }
 121                 if (newPosts.size() == newPostNotification.getElements().size()) {
 122                         return newPostNotification;
 123                 }
 124                 ListNotification<Post> filteredNotification = new ListNotification<Post>(newPostNotification);
 125                 filteredNotification.setElements(newPosts);
 126                 filteredNotification.setLastUpdateTime(newPostNotification.getLastUpdatedTime());
 127                 return filteredNotification;
 128         }
 129
 130         /**
 131          * Filters the new replies of the given notification. If {@code currentSone}
 132          * is {@code null}, {@code null} is returned and the notification is
 133          * subsequently removed. Otherwise only replies that are replies to posts
 134          * that are posted by friend Sones of the given Sone are retained; all other
 135          * replies are removed.
 136          *
 137          * @param newReplyNotification
 138          *            The new-reply notification
 139          * @param currentSone
 140          *            The current Sone, or {@code null} if not logged in
 141          * @return The filtered new-reply notification, or {@code null} if the
 142          *         notification should be removed
 143          */
 144         public static ListNotification<PostReply> filterNewReplyNotification(ListNotification<PostReply> newReplyNotification, Sone currentSone) {
 145                 if (currentSone == null) {
 146                         return null;
 147                 }
 148                 List<PostReply> newReplies = new ArrayList<PostReply>();
 149                 for (PostReply reply : newReplyNotification.getElements()) {
 150                         if (isReplyVisible(currentSone, reply)) {
 151                                 newReplies.add(reply);
 152                         }
 153                 }
 154                 if (newReplies.isEmpty()) {
 155                         return null;
 156                 }
 157                 if (newReplies.size() == newReplyNotification.getElements().size()) {
 158                         return newReplyNotification;
 159                 }
 160                 ListNotification<PostReply> filteredNotification = new ListNotification<PostReply>(newReplyNotification);
 161                 filteredNotification.setElements(newReplies);
 162                 filteredNotification.setLastUpdateTime(newReplyNotification.getLastUpdatedTime());
 163                 return filteredNotification;
 164         }
 165
 166         /**
 167          * Filters the given posts, using {@link #isPostVisible(Sone, Post)} to
 168          * decide whether a post should be contained in the returned list. If
 169          * {@code currentSone} is not {@code null} it is used to filter out posts
 170          * that are from Sones that are not followed or not trusted by the given
 171          * Sone.
 172          *
 173          * @param posts
 174          *            The posts to filter
 175          * @param currentSone
 176          *            The current Sone (may be {@code null})
 177          * @return The filtered posts
 178          */
 179         public static List<Post> filterPosts(Collection<Post> posts, Sone currentSone) {
 180                 List<Post> filteredPosts = new ArrayList<Post>();
 181                 for (Post post : posts) {
 182                         if (isPostVisible(currentSone, post)) {
 183                                 filteredPosts.add(post);
 184                         }
 185                 }
 186                 return filteredPosts;
 187         }
 188
 189         /**
 190          * Checks whether a post is visible to the given Sone. A post is not
 191          * considered visible if one of the following statements is true:
 192          * <ul>
 193          * <li>The post does not have a Sone.</li>
 194          * <li>The post’s {@link Post#getTime() time} is in the future.</li>
 195          * </ul>
 196          * <p>
 197          * If {@code post} is not {@code null} more checks are performed, and the
 198          * post will be invisible if:
 199          * </p>
 200          * <ul>
 201          * <li>The Sone of the post is not the given Sone, the given Sone does not
 202          * follow the post’s Sone, and the given Sone is not the recipient of the
 203          * post.</li>
 204          * <li>The trust relationship between the two Sones can not be retrieved.</li>
 205          * <li>The given Sone has explicitely assigned negative trust to the post’s
 206          * Sone.</li>
 207          * <li>The given Sone has not explicitely assigned negative trust to the
 208          * post’s Sone but the implicit trust is negative.</li>
 209          * </ul>
 210          * If none of these statements is true the post is considered visible.
 211          *
 212          * @param sone
 213          *            The Sone that checks for a post’s visibility (may be
 214          *            {@code null} to skip Sone-specific checks, such as trust)
 215          * @param post
 216          *            The post to check for visibility
 217          * @return {@code true} if the post is considered visible, {@code false}
 218          *         otherwise
 219          */
 220         public static boolean isPostVisible(Sone sone, Post post) {
 221                 Validation.begin().isNotNull("Post", post).check();
 222                 Sone postSone = post.getSone();
 223                 if (postSone == null) {
 224                         return false;
 225                 }
 226                 if (sone != null) {
 227                         Trust trust = postSone.getIdentity().getTrust((OwnIdentity) sone.getIdentity());
 228                         if (trust != null) {
 229                                 if ((trust.getExplicit() != null) && (trust.getExplicit() < 0)) {
 230                                         return false;
 231                                 }
 232                                 if ((trust.getExplicit() == null) && (trust.getImplicit() != null) && (trust.getImplicit() < 0)) {
 233                                         return false;
 234                                 }
 235                         } else {
 236                                 /*
 237                                  * a null trust means that the trust updater has not yet
 238                                  * received a trust value for this relation. if we return false,
 239                                  * the post feed will stay empty until the trust updater has
 240                                  * received trust values. to prevent this we simply assume that
 241                                  * posts are visible if there is no trust.
 242                                  */
 243                                 return true;
 244                         }
 245                         if ((!postSone.equals(sone)) && !sone.hasFriend(postSone.getId()) && !sone.equals(post.getRecipient())) {
 246                                 return false;
 247                         }
 248                 }
 249                 if (post.getTime() > System.currentTimeMillis()) {
 250                         return false;
 251                 }
 252                 return true;
 253         }
 254
 255         /**
 256          * Checks whether a reply is visible to the given Sone. A reply is not
 257          * considered visible if one of the following statements is true:
 258          * <ul>
 259          * <li>The reply does not have a post.</li>
 260          * <li>The reply’s post does not have a Sone.</li>
 261          * <li>The Sone of the reply’s post is not the given Sone, the given Sone
 262          * does not follow the reply’s post’s Sone, and the given Sone is not the
 263          * recipient of the reply’s post.</li>
 264          * <li>The trust relationship between the two Sones can not be retrieved.</li>
 265          * <li>The given Sone has explicitely assigned negative trust to the post’s
 266          * Sone.</li>
 267          * <li>The given Sone has not explicitely assigned negative trust to the
 268          * reply’s post’s Sone but the implicit trust is negative.</li>
 269          * <li>The reply’s post’s {@link Post#getTime() time} is in the future.</li>
 270          * <li>The reply’s {@link Reply#getTime() time} is in the future.</li>
 271          * </ul>
 272          * If none of these statements is true the reply is considered visible.
 273          *
 274          * @param sone
 275          *            The Sone that checks for a post’s visibility (may be
 276          *            {@code null} to skip Sone-specific checks, such as trust)
 277          * @param reply
 278          *            The reply to check for visibility
 279          * @return {@code true} if the reply is considered visible, {@code false}
 280          *         otherwise
 281          */
 282         public static boolean isReplyVisible(Sone sone, PostReply reply) {
 283                 Validation.begin().isNotNull("Reply", reply).check();
 284                 Post post = reply.getPost();
 285                 if (post == null) {
 286                         return false;
 287                 }
 288                 if (!isPostVisible(sone, post)) {
 289                         return false;
 290                 }
 291                 if (reply.getTime() > System.currentTimeMillis()) {
 292                         return false;
 293                 }
 294                 return true;
 295         }
 296
 297 }