Move post-related database functionality into its own class.
[Sone.git] / src / main / java / net / pterodactylus / sone / database / memory / MemoryPostDatabase.java
index eed00ea..fb66162 100644 (file)
-/*
- * Sone - MemoryPostDatabase.java - Copyright © 2013 David Roden
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
 package net.pterodactylus.sone.database.memory;
 
-import static com.google.common.base.Preconditions.checkNotNull;
-
 import java.util.Collection;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
-import java.util.UUID;
 import java.util.concurrent.locks.ReadWriteLock;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 
 import net.pterodactylus.sone.data.Post;
-import net.pterodactylus.sone.data.Sone;
-import net.pterodactylus.sone.data.impl.AbstractPostBuilder;
-import net.pterodactylus.sone.database.PostBuilder;
-import net.pterodactylus.sone.database.PostDatabase;
-import net.pterodactylus.sone.database.SoneProvider;
-import net.pterodactylus.util.config.Configuration;
-import net.pterodactylus.util.config.ConfigurationException;
+import net.pterodactylus.sone.database.DatabaseException;
+import net.pterodactylus.sone.utils.Optionals;
 
+import com.google.common.base.Function;
 import com.google.common.base.Optional;
-import com.google.inject.Inject;
+import com.google.common.collect.FluentIterable;
+import com.google.common.collect.HashMultimap;
+import com.google.common.collect.Multimap;
 
 /**
- * Memory-based {@link PostDatabase} implementation.
+ * Groups {@link Post}-related database functions.
  *
  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  */
-public class MemoryPostDatabase implements PostDatabase {
+class MemoryPostDatabase {
 
-       /** The lock. */
        private final ReadWriteLock lock = new ReentrantReadWriteLock();
-
-       /** The Sone provider. */
-       private final SoneProvider soneProvider;
-
-       /** All posts by their ID. */
-       private final Map<String, Post> allPosts = new HashMap<String, Post>();
-
-       /** All posts by their Sones. */
-       private final Map<String, Collection<Post>> sonePosts = new HashMap<String, Collection<Post>>();
-
-       /** All posts by their recipient. */
-       private final Map<String, Collection<Post>> recipientPosts = new HashMap<String, Collection<Post>>();
-
-       /** Whether posts are known. */
+       private final MemoryDatabase database;
+       private final ConfigurationLoader configurationLoader;
+       private final Multimap<String, String> sonePosts = HashMultimap.create();
+       private final Map<String, String> postSones = new HashMap<String, String>();
+       private final Map<String, Long> postTimes = new HashMap<String, Long>();
+       private final Map<String, String> postRecipients = new HashMap<String, String>();
+       private final Multimap<String, String> recipientPosts = HashMultimap.create();
+       private final Map<String, String> postTexts = new HashMap<String, String>();
        private final Set<String> knownPosts = new HashSet<String>();
 
-       /**
-        * Creates a new memory database.
-        *
-        * @param soneProvider
-        *            The Sone provider
-        */
-       @Inject
-       public MemoryPostDatabase(SoneProvider soneProvider) {
-               this.soneProvider = soneProvider;
+       MemoryPostDatabase(MemoryDatabase database, ConfigurationLoader configurationLoader) {
+               this.database = database;
+               this.configurationLoader = configurationLoader;
        }
 
-       //
-       // POSTPROVIDER METHODS
-       //
-
-       /**
-        * {@inheritDocs}
-        */
-       @Override
-       public Optional<Post> getPost(String postId) {
-               lock.readLock().lock();
-               try {
-                       return Optional.fromNullable(allPosts.get(postId));
-               } finally {
-                       lock.readLock().unlock();
-               }
+       void start() {
+               loadKnownPosts();
        }
 
-       /**
-        * {@inheritDocs}
-        */
-       @Override
-       public Collection<Post> getPosts(String soneId) {
-               return new HashSet<Post>(getPostsFrom(soneId));
+       void stop() {
+               saveKnownPosts();
        }
 
-       /**
-        * {@inheritDocs}
-        */
-       @Override
-       public Collection<Post> getDirectedPosts(String recipientId) {
+       Optional<Post> getPost(String postId) {
                lock.readLock().lock();
                try {
-                       Collection<Post> posts = recipientPosts.get(recipientId);
-                       return (posts == null) ? Collections.<Post> emptySet() : new HashSet<Post>(posts);
+                       if (!postSones.containsKey(postId)) {
+                               return Optional.absent();
+                       }
+                       String sender = postSones.get(postId);
+                       String recipientId = postRecipients.get(postId);
+                       long time = postTimes.get(postId);
+                       String text = postTexts.get(postId);
+                       return Optional.<Post>of(
+                                       new MemoryPost(database, database, postId, sender, recipientId, time, text));
                } finally {
                        lock.readLock().unlock();
                }
        }
 
-       //
-       // POSTBUILDERFACTORY METHODS
-       //
-
-       /**
-        * {@inheritDocs}
-        */
-       @Override
-       public PostBuilder newPostBuilder() {
-               return new MemoryPostBuilder(soneProvider);
-       }
-
-       //
-       // POSTSTORE METHODS
-       //
-
-       /**
-        * {@inheritDocs}
-        */
-       @Override
-       public void storePost(Post post) {
-               checkNotNull(post, "post must not be null");
-               lock.writeLock().lock();
+       Collection<Post> getPostsFrom(String soneId) {
+               lock.readLock().lock();
                try {
-                       allPosts.put(post.getId(), post);
-                       getPostsFrom(post.getSone().getId()).add(post);
-                       if (post.getRecipientId().isPresent()) {
-                               getPostsTo(post.getRecipientId().get()).add(post);
-                       }
+                       return FluentIterable.from(sonePosts.get(soneId))
+                                       .transform(postLoader)
+                                       .transform(Optionals.<Post>get())
+                                       .toList();
                } finally {
-                       lock.writeLock().unlock();
+                       lock.readLock().unlock();
                }
        }
 
-       /**
-        * {@inheritDocs}
-        */
-       @Override
-       public void removePost(Post post) {
-               checkNotNull(post, "post must not be null");
-               lock.writeLock().lock();
+       Collection<Post> getDirectedPosts(String recipientId) {
+               lock.readLock().lock();
                try {
-                       allPosts.remove(post.getId());
-                       getPostsFrom(post.getSone().getId()).remove(post);
-                       if (post.getRecipientId().isPresent()) {
-                               getPostsTo(post.getRecipientId().get()).remove(post);
-                       }
-                       post.getSone().removePost(post);
+                       return FluentIterable.from(recipientPosts.get(recipientId))
+                                       .transform(postLoader)
+                                       .transform(Optionals.<Post>get())
+                                       .toList();
                } finally {
-                       lock.writeLock().unlock();
+                       lock.readLock().unlock();
                }
        }
 
-       /**
-        * {@inheritDocs}
-        */
-       @Override
-       public void storePosts(Sone sone, Collection<Post> posts) throws IllegalArgumentException {
-               checkNotNull(sone, "sone must not be null");
-               /* verify that all posts are from the same Sone. */
-               for (Post post : posts) {
-                       if (!sone.equals(post.getSone())) {
-                               throw new IllegalArgumentException(String.format("Post from different Sone found: %s", post));
-                       }
-               }
-
+       void storePosts(String soneId, Collection<Post> posts) {
                lock.writeLock().lock();
                try {
-                       /* remove all posts by the Sone. */
-                       getPostsFrom(sone.getId()).clear();
+                       removePostsFor(soneId);
                        for (Post post : posts) {
-                               allPosts.remove(post.getId());
-                               if (post.getRecipientId().isPresent()) {
-                                       getPostsTo(post.getRecipientId().get()).remove(post);
-                               }
-                       }
-
-                       /* add new posts. */
-                       getPostsFrom(sone.getId()).addAll(posts);
-                       for (Post post : posts) {
-                               allPosts.put(post.getId(), post);
-                               if (post.getRecipientId().isPresent()) {
-                                       getPostsTo(post.getRecipientId().get()).add(post);
-                               }
+                               storePost(post);
                        }
                } finally {
                        lock.writeLock().unlock();
                }
        }
 
-       /**
-        * {@inheritDocs}
-        */
-       @Override
-       public void removePosts(Sone sone) {
-               checkNotNull(sone, "sone must not be null");
-               lock.writeLock().lock();
-               try {
-                       /* remove all posts by the Sone. */
-                       getPostsFrom(sone.getId()).clear();
-                       for (Post post : sone.getPosts()) {
-                               allPosts.remove(post.getId());
-                               if (post.getRecipientId().isPresent()) {
-                                       getPostsTo(post.getRecipientId().get()).remove(post);
-                               }
-                       }
-               } finally {
-                       lock.writeLock().unlock();
+       void storePost(Post post) {
+               String soneId = post.getSone().getId();
+               final String postId = post.getId();
+               sonePosts.put(soneId, postId);
+               postSones.put(postId, soneId);
+               postRecipients.put(postId, post.getRecipientId().orNull());
+               if (post.getRecipientId().isPresent()) {
+                       recipientPosts.put(post.getRecipientId().get(), postId);
                }
+               postTimes.put(postId, post.getTime());
+               postTexts.put(postId, post.getText());
        }
 
-       //
-       // POSTDATABASE METHODS
-       //
-
-       /**
-        * {@inheritDocs}
-        */
-       @Override
-       public void loadKnownPosts(Configuration configuration, String prefix) {
+       void removePostsFor(String soneId) {
                lock.writeLock().lock();
                try {
-                       int postCounter = 0;
-                       while (true) {
-                               String knownPostId = configuration.getStringValue(prefix + postCounter++ + "/ID").getValue(null);
-                               if (knownPostId == null) {
-                                       break;
-                               }
-                               knownPosts.add(knownPostId);
+                       for (String postId : sonePosts.removeAll(soneId)) {
+                               removePost(postId);
                        }
                } finally {
                        lock.writeLock().unlock();
                }
        }
 
-       /**
-        * {@inheritDocs}
-        */
-       @Override
-       public void saveKnownPosts(Configuration configuration, String prefix) throws ConfigurationException {
-               lock.readLock().lock();
+       void removePost(String postId) {
+               lock.writeLock().lock();
                try {
-                       int postCounter = 0;
-                       for (String knownPostId : knownPosts) {
-                               configuration.getStringValue(prefix + postCounter++ + "/ID").setValue(knownPostId);
+                       postSones.remove(postId);
+                       String recipient = postRecipients.remove(postId);
+                       if (recipient != null) {
+                               recipientPosts.remove(recipient, postId);
                        }
-                       configuration.getStringValue(prefix + postCounter + "/ID").setValue(null);
+                       postTimes.remove(postId);
+                       postTexts.remove(postId);
                } finally {
-                       lock.readLock().unlock();
+                       lock.writeLock().unlock();
                }
        }
 
-       //
-       // PACKAGE-PRIVATE METHODS
-       //
-
-       /**
-        * Returns whether the given post is known.
-        *
-        * @param post
-        *            The post
-        * @return {@code true} if the post is known, {@code false} otherwise
-        */
-       boolean isPostKnown(Post post) {
+       boolean isPostKnown(String postId) {
                lock.readLock().lock();
                try {
-                       return knownPosts.contains(post.getId());
+                       return knownPosts.contains(postId);
                } finally {
                        lock.readLock().unlock();
                }
        }
 
-       /**
-        * Sets whether the given post is known.
-        *
-        * @param post
-        *            The post
-        * @param known
-        *            {@code true} if the post is known, {@code false} otherwise
-        */
-       void setPostKnown(Post post, boolean known) {
+       void setPostKnown(String postId, boolean known) {
                lock.writeLock().lock();
                try {
                        if (known) {
-                               knownPosts.add(post.getId());
+                               knownPosts.add(postId);
                        } else {
-                               knownPosts.remove(post.getId());
+                               knownPosts.remove(postId);
                        }
+                       saveKnownPosts();
                } finally {
                        lock.writeLock().unlock();
                }
        }
 
-       //
-       // PRIVATE METHODS
-       //
-
-       /**
-        * Gets all posts for the given Sone, creating a new collection if there is
-        * none yet.
-        *
-        * @param soneId
-        *            The ID of the Sone to get the posts for
-        * @return All posts
-        */
-       private Collection<Post> getPostsFrom(String soneId) {
-               Collection<Post> posts = null;
-               lock.readLock().lock();
-               try {
-                       posts = sonePosts.get(soneId);
-               } finally {
-                       lock.readLock().unlock();
-               }
-               if (posts != null) {
-                       return posts;
-               }
-
-               posts = new HashSet<Post>();
+       private void loadKnownPosts() {
+               Set<String> knownPosts = configurationLoader.loadKnownPosts();
                lock.writeLock().lock();
                try {
-                       sonePosts.put(soneId, posts);
+                       this.knownPosts.clear();
+                       this.knownPosts.addAll(knownPosts);
                } finally {
                        lock.writeLock().unlock();
                }
-
-               return posts;
        }
 
-       /**
-        * Gets all posts that are directed the given Sone, creating a new
-        * collection if there is none yet.
-        *
-        * @param recipientId
-        *            The ID of the Sone to get the posts for
-        * @return All posts
-        */
-       private Collection<Post> getPostsTo(String recipientId) {
-               Collection<Post> posts = null;
+       private void saveKnownPosts() {
                lock.readLock().lock();
                try {
-                       posts = recipientPosts.get(recipientId);
+                       configurationLoader.saveKnownPosts(knownPosts);
                } finally {
                        lock.readLock().unlock();
                }
-               if (posts != null) {
-                       return posts;
-               }
-
-               posts = new HashSet<Post>();
-               lock.writeLock().lock();
-               try {
-                       recipientPosts.put(recipientId, posts);
-               } finally {
-                       lock.writeLock().unlock();
-               }
-
-               return posts;
        }
 
-       /**
-        * {@link PostBuilder} implementation that creates a {@link MemoryPost}.
-        *
-        * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
-        */
-       private class MemoryPostBuilder extends AbstractPostBuilder {
-
-               /**
-                * Creates a new memory post builder.
-                *
-                * @param soneProvider
-                *            The Sone provider
-                */
-               public MemoryPostBuilder(SoneProvider soneProvider) {
-                       super(soneProvider);
-               }
-
-               /**
-                * {@inheritDocs}
-                */
+       private Function<String, Optional<Post>> postLoader = new Function<String, Optional<Post>>() {
                @Override
-               public Post build() throws IllegalStateException {
-                       validate();
-                       Post post = new MemoryPost(MemoryPostDatabase.this, soneProvider, randomId ? UUID.randomUUID().toString() : id, senderId, recipientId, currentTime ? System.currentTimeMillis() : time, text);
-                       post.setKnown(isPostKnown(post));
-                       return post;
+               public Optional<Post> apply(String input) {
+                       return getPost(input);
                }
-
-       }
+       };
 
 }