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

   1 /*
   2  * Sone - ListNotificationFilters.java - Copyright © 2010–2013 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 static com.google.common.base.Preconditions.checkNotNull;
  21
  22 import java.util.ArrayList;
  23 import java.util.Collection;
  24 import java.util.List;
  25
  26 import net.pterodactylus.sone.data.Post;
  27 import net.pterodactylus.sone.data.PostReply;
  28 import net.pterodactylus.sone.data.Reply;
  29 import net.pterodactylus.sone.data.Sone;
  30 import net.pterodactylus.sone.freenet.wot.OwnIdentity;
  31 import net.pterodactylus.sone.freenet.wot.Trust;
  32 import net.pterodactylus.util.notify.Notification;
  33
  34 import com.google.common.base.Optional;
  35
  36 /**
  37  * Filter for {@link ListNotification}s.
  38  *
  39  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  40  */
  41 public class ListNotificationFilters {
  42
  43         /**
  44          * Filters new-post and new-reply notifications in the given list of
  45          * notifications. If {@code currentSone} is <code>null</code>, new-post and
  46          * new-reply notifications are removed completely. If {@code currentSone} is
  47          * not {@code null}, only posts that are posted by a friend Sone or the Sone
  48          * itself, and replies that are replies to posts of friend Sones or the Sone
  49          * itself will be retained in the notifications.
  50          *
  51          * @param notifications
  52          *            The notifications to filter
  53          * @param currentSone
  54          *            The current Sone, or {@code null} if not logged in
  55          * @return The filtered notifications
  56          */
  57         @SuppressWarnings("unchecked")
  58         public static List<Notification> filterNotifications(Collection<? extends Notification> notifications, Sone currentSone) {
  59                 List<Notification> filteredNotifications = new ArrayList<Notification>();
  60                 for (Notification notification : notifications) {
  61                         if (notification.getId().equals("new-sone-notification")) {
  62                                 if ((currentSone != null) && !currentSone.getOptions().isShowNewSoneNotifications()) {
  63                                         continue;
  64                                 }
  65                                 filteredNotifications.add(notification);
  66                         } else if (notification.getId().equals("new-post-notification")) {
  67                                 if ((currentSone != null) && !currentSone.getOptions().isShowNewPostNotifications()) {
  68                                         continue;
  69                                 }
  70                                 ListNotification<Post> filteredNotification = filterNewPostNotification((ListNotification<Post>) notification, currentSone, true);
  71                                 if (filteredNotification != null) {
  72                                         filteredNotifications.add(filteredNotification);
  73                                 }
  74                         } else if (notification.getId().equals("new-reply-notification")) {
  75                                 if ((currentSone != null) && !currentSone.getOptions().isShowNewReplyNotifications()) {
  76                                         continue;
  77                                 }
  78                                 ListNotification<PostReply> filteredNotification = filterNewReplyNotification((ListNotification<PostReply>) notification, currentSone);
  79                                 if (filteredNotification != null) {
  80                                         filteredNotifications.add(filteredNotification);
  81                                 }
  82                         } else if (notification.getId().equals("mention-notification")) {
  83                                 ListNotification<Post> filteredNotification = filterNewPostNotification((ListNotification<Post>) notification, null, false);
  84                                 if (filteredNotification != null) {
  85                                         filteredNotifications.add(filteredNotification);
  86                                 }
  87                         } else {
  88                                 filteredNotifications.add(notification);
  89                         }
  90                 }
  91                 return filteredNotifications;
  92         }
  93
  94         /**
  95          * Filters the new posts of the given notification. If {@code currentSone}
  96          * is {@code null} and {@code soneRequired} is {@code true}, {@code null} is
  97          * returned and the notification is subsequently removed. Otherwise only
  98          * posts that are posted by friend Sones of the given Sone are retained; all
  99          * other posts are removed.
 100          *
 101          * @param newPostNotification
 102          *            The new-post notification
 103          * @param currentSone
 104          *            The current Sone, or {@code null} if not logged in
 105          * @param soneRequired
 106          *            Whether a non-{@code null} Sone in {@code currentSone} is
 107          *            required
 108          * @return The filtered new-post notification, or {@code null} if the
 109          *         notification should be removed
 110          */
 111         public static ListNotification<Post> filterNewPostNotification(ListNotification<Post> newPostNotification, Sone currentSone, boolean soneRequired) {
 112                 if (soneRequired && (currentSone == null)) {
 113                         return null;
 114                 }
 115                 List<Post> newPosts = new ArrayList<Post>();
 116                 for (Post post : newPostNotification.getElements()) {
 117                         if (isPostVisible(currentSone, post)) {
 118                                 newPosts.add(post);
 119                         }
 120                 }
 121                 if (newPosts.isEmpty()) {
 122                         return null;
 123                 }
 124                 if (newPosts.size() == newPostNotification.getElements().size()) {
 125                         return newPostNotification;
 126                 }
 127                 ListNotification<Post> filteredNotification = new ListNotification<Post>(newPostNotification);
 128                 filteredNotification.setElements(newPosts);
 129                 filteredNotification.setLastUpdateTime(newPostNotification.getLastUpdatedTime());
 130                 return filteredNotification;
 131         }
 132
 133         /**
 134          * Filters the new replies of the given notification. If {@code currentSone}
 135          * is {@code null}, {@code null} is returned and the notification is
 136          * subsequently removed. Otherwise only replies that are replies to posts
 137          * that are posted by friend Sones of the given Sone are retained; all other
 138          * replies are removed.
 139          *
 140          * @param newReplyNotification
 141          *            The new-reply notification
 142          * @param currentSone
 143          *            The current Sone, or {@code null} if not logged in
 144          * @return The filtered new-reply notification, or {@code null} if the
 145          *         notification should be removed
 146          */
 147         public static ListNotification<PostReply> filterNewReplyNotification(ListNotification<PostReply> newReplyNotification, Sone currentSone) {
 148                 if (currentSone == null) {
 149                         return null;
 150                 }
 151                 List<PostReply> newReplies = new ArrayList<PostReply>();
 152                 for (PostReply reply : newReplyNotification.getElements()) {
 153                         if (isReplyVisible(currentSone, reply)) {
 154                                 newReplies.add(reply);
 155                         }
 156                 }
 157                 if (newReplies.isEmpty()) {
 158                         return null;
 159                 }
 160                 if (newReplies.size() == newReplyNotification.getElements().size()) {
 161                         return newReplyNotification;
 162                 }
 163                 ListNotification<PostReply> filteredNotification = new ListNotification<PostReply>(newReplyNotification);
 164                 filteredNotification.setElements(newReplies);
 165                 filteredNotification.setLastUpdateTime(newReplyNotification.getLastUpdatedTime());
 166                 return filteredNotification;
 167         }
 168
 169         /**
 170          * Filters the given posts, using {@link #isPostVisible(Sone, Post)} to
 171          * decide whether a post should be contained in the returned list. If
 172          * {@code currentSone} is not {@code null} it is used to filter out posts
 173          * that are from Sones that are not followed or not trusted by the given
 174          * Sone.
 175          *
 176          * @param posts
 177          *            The posts to filter
 178          * @param currentSone
 179          *            The current Sone (may be {@code null})
 180          * @return The filtered posts
 181          */
 182         public static List<Post> filterPosts(Collection<Post> posts, Sone currentSone) {
 183                 List<Post> filteredPosts = new ArrayList<Post>();
 184                 for (Post post : posts) {
 185                         if (isPostVisible(currentSone, post)) {
 186                                 filteredPosts.add(post);
 187                         }
 188                 }
 189                 return filteredPosts;
 190         }
 191
 192         /**
 193          * Checks whether a post is visible to the given Sone. A post is not
 194          * considered visible if one of the following statements is true:
 195          * <ul>
 196          * <li>The post does not have a Sone.</li>
 197          * <li>The post’s {@link Post#getTime() time} is in the future.</li>
 198          * </ul>
 199          * <p>
 200          * If {@code post} is not {@code null} more checks are performed, and the
 201          * post will be invisible if:
 202          * </p>
 203          * <ul>
 204          * <li>The Sone of the post is not the given Sone, the given Sone does not
 205          * follow the post’s Sone, and the given Sone is not the recipient of the
 206          * post.</li>
 207          * <li>The trust relationship between the two Sones can not be retrieved.</li>
 208          * <li>The given Sone has explicitely assigned negative trust to the post’s
 209          * Sone.</li>
 210          * <li>The given Sone has not explicitely assigned negative trust to the
 211          * post’s Sone but the implicit trust is negative.</li>
 212          * </ul>
 213          * If none of these statements is true the post is considered visible.
 214          *
 215          * @param sone
 216          *            The Sone that checks for a post’s visibility (may be
 217          *            {@code null} to skip Sone-specific checks, such as trust)
 218          * @param post
 219          *            The post to check for visibility
 220          * @return {@code true} if the post is considered visible, {@code false}
 221          *         otherwise
 222          */
 223         public static boolean isPostVisible(Sone sone, Post post) {
 224                 checkNotNull(post, "post must not be null");
 225                 if (!post.isLoaded()) {
 226                         return false;
 227                 }
 228                 Sone postSone = post.getSone();
 229                 if (sone != null) {
 230                         Trust trust = postSone.getIdentity().getTrust((OwnIdentity) sone.getIdentity());
 231                         if (trust != null) {
 232                                 if ((trust.getExplicit() != null) && (trust.getExplicit() < 0)) {
 233                                         return false;
 234                                 }
 235                                 if ((trust.getExplicit() == null) && (trust.getImplicit() != null) && (trust.getImplicit() < 0)) {
 236                                         return false;
 237                                 }
 238                         } else {
 239                                 /*
 240                                  * a null trust means that the trust updater has not yet
 241                                  * received a trust value for this relation. if we return false,
 242                                  * the post feed will stay empty until the trust updater has
 243                                  * received trust values. to prevent this we simply assume that
 244                                  * posts are visible if there is no trust.
 245                                  */
 246                         }
 247                         if ((!postSone.equals(sone)) && !sone.hasFriend(postSone.getId()) && !sone.getId().equals(post.getRecipientId().orNull())) {
 248                                 return false;
 249                         }
 250                 }
 251                 if (post.getTime() > System.currentTimeMillis()) {
 252                         return false;
 253                 }
 254                 return true;
 255         }
 256
 257         /**
 258          * Checks whether a reply is visible to the given Sone. A reply is not
 259          * considered visible if one of the following statements is true:
 260          * <ul>
 261          * <li>The reply does not have a post.</li>
 262          * <li>The reply’s post does not have a Sone.</li>
 263          * <li>The Sone of the reply’s post is not the given Sone, the given Sone
 264          * does not follow the reply’s post’s Sone, and the given Sone is not the
 265          * recipient of the reply’s post.</li>
 266          * <li>The trust relationship between the two Sones can not be retrieved.</li>
 267          * <li>The given Sone has explicitely assigned negative trust to the post’s
 268          * Sone.</li>
 269          * <li>The given Sone has not explicitely assigned negative trust to the
 270          * reply’s post’s Sone but the implicit trust is negative.</li>
 271          * <li>The reply’s post’s {@link Post#getTime() time} is in the future.</li>
 272          * <li>The reply’s {@link Reply#getTime() time} is in the future.</li>
 273          * </ul>
 274          * If none of these statements is true the reply is considered visible.
 275          *
 276          * @param sone
 277          *            The Sone that checks for a post’s visibility (may be
 278          *            {@code null} to skip Sone-specific checks, such as trust)
 279          * @param reply
 280          *            The reply to check for visibility
 281          * @return {@code true} if the reply is considered visible, {@code false}
 282          *         otherwise
 283          */
 284         public static boolean isReplyVisible(Sone sone, PostReply reply) {
 285                 checkNotNull(reply, "reply must not be null");
 286                 Optional<Post> post = reply.getPost();
 287                 if (!post.isPresent()) {
 288                         return false;
 289                 }
 290                 if (!isPostVisible(sone, post.get())) {
 291                         return false;
 292                 }
 293                 if (reply.getTime() > System.currentTimeMillis()) {
 294                         return false;
 295                 }
 296                 return true;
 297         }
 298
 299 }