Refactor notification filtering

[Sone.git] / src / main / java / net / pterodactylus / sone / notify / ReplyVisibilityFilter.java

diff --git a/src/main/java/net/pterodactylus/sone/notify/ReplyVisibilityFilter.java b/src/main/java/net/pterodactylus/sone/notify/ReplyVisibilityFilter.java
new file mode 100644 (file)
index 0000000..a76ae25
--- /dev/null
+++ b/src/main/java/net/pterodactylus/sone/notify/ReplyVisibilityFilter.java
@@ -0,0 +1,73 @@
+package net.pterodactylus.sone.notify;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+import net.pterodactylus.sone.data.Post;
+import net.pterodactylus.sone.data.PostReply;
+import net.pterodactylus.sone.data.Sone;
+
+import com.google.common.base.Optional;
+import com.google.common.base.Predicate;
+
+/**
+ * Filter that checks a {@link PostReply} for visibility.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+@Singleton
+public class ReplyVisibilityFilter {
+
+       private final PostVisibilityFilter postVisibilityFilter;
+
+       @Inject
+       public ReplyVisibilityFilter(@Nonnull PostVisibilityFilter postVisibilityFilter) {
+               this.postVisibilityFilter = postVisibilityFilter;
+       }
+
+       /**
+        * Checks whether a reply is visible to the given Sone. A reply is not
+        * considered visible if one of the following statements is true:
+        * <ul>
+        * <li>The reply does not have a post.</li>
+        * <li>The reply’s post {@link PostVisibilityFilter#isPostVisible(Sone, Post) is not visible}.</li>
+        * <li>The reply’s {@link PostReply#getTime() time} is in the future.</li>
+        * </ul>
+        * If none of these statements is true the reply is considered visible.
+        *
+        * @param sone
+        *              The Sone that checks for a post’s visibility (may be
+        *              {@code null} to skip Sone-specific checks, such as trust)
+        * @param reply
+        *              The reply to check for visibility
+        * @return {@code true} if the reply is considered visible, {@code false}
+        * otherwise
+        */
+       boolean isReplyVisible(@Nullable Sone sone, @Nonnull PostReply reply) {
+               checkNotNull(reply, "reply must not be null");
+               Optional<Post> post = reply.getPost();
+               if (!post.isPresent()) {
+                       return false;
+               }
+               if (!postVisibilityFilter.isPostVisible(sone, post.get())) {
+                       return false;
+               }
+               return reply.getTime() <= System.currentTimeMillis();
+       }
+
+       @Nonnull
+       public Predicate<PostReply> isVisible(@Nullable final Sone currentSone) {
+               return new Predicate<PostReply>() {
+                       @Nonnull
+                       @Override
+                       public boolean apply(@Nullable PostReply postReply) {
+                               return isReplyVisible(currentSone, postReply);
+                       }
+               };
+       }
+
+}