X-Git-Url: https://git.pterodactylus.net/?a=blobdiff_plain;f=src%2Fmain%2Fjava%2Fnet%2Fpterodactylus%2Fsone%2Fcore%2FSoneChangeDetector.java;fp=src%2Fmain%2Fjava%2Fnet%2Fpterodactylus%2Fsone%2Fcore%2FSoneChangeDetector.java;h=efcdc6effed5606769dd74922b825105f2a31f97;hb=bae04bf1966d021bd57d5cfc827e8f2b1cd247ce;hp=0000000000000000000000000000000000000000;hpb=39ad8597b568c51f095c07a8de4f5424db185d8e;p=Sone.git

diff --git a/src/main/java/net/pterodactylus/sone/core/SoneChangeDetector.java b/src/main/java/net/pterodactylus/sone/core/SoneChangeDetector.java
new file mode 100644
index 0000000..efcdc6e
--- /dev/null
+++ b/src/main/java/net/pterodactylus/sone/core/SoneChangeDetector.java
@@ -0,0 +1,114 @@
+package net.pterodactylus.sone.core;
+
+import static com.google.common.base.Optional.absent;
+import static com.google.common.base.Optional.fromNullable;
+import static com.google.common.collect.FluentIterable.from;
+
+import java.util.Collection;
+
+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;
+import com.google.common.collect.FluentIterable;
+
+/**
+ * Compares the contents of two {@link Sone}s and fires events for new and
+ * removed elements.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public class SoneChangeDetector {
+
+	private final Sone oldSone;
+	private Optional<PostProcessor> newPostProcessor = absent();
+	private Optional<PostProcessor> removedPostProcessor = absent();
+	private Optional<PostReplyProcessor> newPostReplyProcessor = absent();
+	private Optional<PostReplyProcessor> removedPostReplyProcessor = absent();
+
+	public SoneChangeDetector(Sone oldSone) {
+		this.oldSone = oldSone;
+	}
+
+	public void onNewPosts(PostProcessor newPostProcessor) {
+		this.newPostProcessor = fromNullable(newPostProcessor);
+	}
+
+	public void onRemovedPosts(PostProcessor removedPostProcessor) {
+		this.removedPostProcessor = fromNullable(removedPostProcessor);
+	}
+
+	public void onNewPostReplies(PostReplyProcessor newPostReplyProcessor) {
+		this.newPostReplyProcessor = fromNullable(newPostReplyProcessor);
+	}
+
+	public void onRemovedPostReplies(
+			PostReplyProcessor removedPostReplyProcessor) {
+		this.removedPostReplyProcessor = fromNullable(removedPostReplyProcessor);
+	}
+
+	public void detectChanges(Sone newSone) {
+		processPosts(from(newSone.getPosts()).filter(
+				notContainedIn(oldSone.getPosts())), newPostProcessor);
+		processPosts(from(oldSone.getPosts()).filter(
+				notContainedIn(newSone.getPosts())), removedPostProcessor);
+		processPostReplies(from(newSone.getReplies()).filter(
+				notContainedIn(oldSone.getReplies())), newPostReplyProcessor);
+		processPostReplies(from(oldSone.getReplies()).filter(
+				notContainedIn(newSone.getReplies())), removedPostReplyProcessor);
+	}
+
+	private void processPostReplies(FluentIterable<PostReply> postReplies,
+			Optional<PostReplyProcessor> postReplyProcessor) {
+		for (PostReply postReply : postReplies) {
+			notifyPostReplyProcessor(postReplyProcessor, postReply);
+		}
+	}
+
+	private void notifyPostReplyProcessor(
+			Optional<PostReplyProcessor> postReplyProcessor,
+			PostReply postReply) {
+		if (postReplyProcessor.isPresent()) {
+			postReplyProcessor.get()
+					.processPostReply(postReply);
+		}
+	}
+
+	private void processPosts(FluentIterable<Post> posts,
+			Optional<PostProcessor> newPostProcessor) {
+		for (Post post : posts) {
+			notifyPostProcessor(newPostProcessor, post);
+		}
+	}
+
+	private void notifyPostProcessor(Optional<PostProcessor> postProcessor,
+			Post newPost) {
+		if (postProcessor.isPresent()) {
+			postProcessor.get().processPost(newPost);
+		}
+	}
+
+	private <T> Predicate<T> notContainedIn(final Collection<T> posts) {
+		return new Predicate<T>() {
+			@Override
+			public boolean apply(T element) {
+				return !posts.contains(element);
+			}
+		};
+	}
+
+	public interface PostProcessor {
+
+		void processPost(Post post);
+
+	}
+
+	public interface PostReplyProcessor {
+
+		void processPostReply(PostReply postReply);
+
+	}
+
+}