Blog Client with Factory and Validator

This implements a simple initial blog client that covers the basic blog
actions, but no deletion/removal of blogs, yet.

Classes for Blogs and Blog Post Headers have been introduced along with
the associated factories.

A `BlogPostValidator` has been added that validates incoming blog posts.

Closes #402
Closes #404

briar-api/src/org/briarproject/api/blogs/Blog.java

@@ -0,0 +1,32 @@
+package org.briarproject.api.blogs;
+
+import org.briarproject.api.forum.Forum;
+import org.briarproject.api.identity.Author;
+import org.briarproject.api.sync.Group;
+import org.jetbrains.annotations.NotNull;
+
+public class Blog extends Forum {
+
+	@NotNull
+	private final String description;
+	@NotNull
+	private final Author author;
+
+	public Blog(@NotNull Group group, @NotNull String name,
+			@NotNull String description, @NotNull Author author) {
+		super(group, name, null);
+
+		this.description = description;
+		this.author = author;
+	}
+
+	@NotNull
+	public String getDescription() {
+		return description;
+	}
+
+	@NotNull
+	public Author getAuthor() {
+		return author;
+	}
+}

briar-api/src/org/briarproject/api/blogs/BlogConstants.java

@@ -0,0 +1,39 @@
+package org.briarproject.api.blogs;
+
+import static org.briarproject.api.sync.SyncConstants.MAX_MESSAGE_BODY_LENGTH;
+
+public interface BlogConstants {
+
+	/** The maximum length of a blogs's name in UTF-8 bytes. */
+	int MAX_BLOG_TITLE_LENGTH = 100;
+
+	/** The length of a blogs's description in UTF-8 bytes. */
+	int MAX_BLOG_DESC_LENGTH = 240;
+
+	/** The maximum length of a blog post's content type in UTF-8 bytes. */
+	int MAX_CONTENT_TYPE_LENGTH = 50;
+
+	/** The length of a blog post's title in UTF-8 bytes. */
+	int MAX_BLOG_POST_TITLE_LENGTH = 100;
+
+	/** The length of a blog post's teaser in UTF-8 bytes. */
+	int MAX_BLOG_POST_TEASER_LENGTH = 240;
+
+	/** The maximum length of a blog post's body in bytes. */
+	int MAX_BLOG_POST_BODY_LENGTH = MAX_MESSAGE_BODY_LENGTH - 1024;
+
+	// Metadata keys
+	String KEY_DESCRIPTION = "description";
+	String KEY_TITLE = "title";
+	String KEY_TEASER = "teaser";
+	String KEY_HAS_BODY = "hasBody";
+	String KEY_TIMESTAMP = "timestamp";
+	String KEY_PARENT = "parent";
+	String KEY_AUTHOR_ID = "id";
+	String KEY_AUTHOR_NAME = "name";
+	String KEY_PUBLIC_KEY = "publicKey";
+	String KEY_AUTHOR = "author";
+	String KEY_CONTENT_TYPE = "contentType";
+	String KEY_READ = "read";
+
+}

briar-api/src/org/briarproject/api/blogs/BlogFactory.java

@@ -0,0 +1,17 @@
+package org.briarproject.api.blogs;
+
+import org.briarproject.api.FormatException;
+import org.briarproject.api.identity.Author;
+import org.briarproject.api.sync.Group;
+import org.jetbrains.annotations.NotNull;
+
+public interface BlogFactory {
+
+	/** Creates a blog with the given name, description and author. */
+	Blog createBlog(@NotNull String name, @NotNull String description,
+			@NotNull Author author);
+
+	/** Parses a blog with the given Group and description */
+	Blog parseBlog(@NotNull Group g, @NotNull String description)
+			throws FormatException;
+}

briar-api/src/org/briarproject/api/blogs/BlogManager.java

@@ -0,0 +1,48 @@
+package org.briarproject.api.blogs;
+
+import org.briarproject.api.FormatException;
+import org.briarproject.api.db.DbException;
+import org.briarproject.api.db.Transaction;
+import org.briarproject.api.identity.LocalAuthor;
+import org.briarproject.api.sync.ClientId;
+import org.briarproject.api.sync.GroupId;
+import org.briarproject.api.sync.MessageId;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Collection;
+
+public interface BlogManager {
+
+	/** Returns the unique ID of the blog client. */
+	ClientId getClientId();
+
+	/** Creates a new Blog. */
+	Blog addBlog(LocalAuthor localAuthor, String name, String description)
+			throws DbException;
+
+	/** Stores a local blog post. */
+	void addLocalPost(BlogPost p) throws DbException;
+
+	/** Returns the blog with the given ID. */
+	Blog getBlog(GroupId g) throws DbException;
+
+	/** Returns the blog with the given ID. */
+	Blog getBlog(Transaction txn, GroupId g) throws DbException;
+
+	/** Returns all blogs to which the localAuthor created. */
+	Collection<Blog> getBlogs(LocalAuthor localAuthor) throws DbException;
+
+	/** Returns all blogs to which the user subscribes. */
+	Collection<Blog> getBlogs() throws DbException;
+
+	/** Returns the body of the blog post with the given ID. */
+	@Nullable
+	byte[] getPostBody(MessageId m) throws DbException;
+
+	/** Returns the headers of all posts in the given blog. */
+	Collection<BlogPostHeader> getPostHeaders(GroupId g) throws DbException;
+
+	/** Marks a blog post as read or unread. */
+	void setReadFlag(MessageId m, boolean read) throws DbException;
+
+}

briar-api/src/org/briarproject/api/blogs/BlogPost.java

@@ -0,0 +1,43 @@
+package org.briarproject.api.blogs;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import org.briarproject.api.forum.ForumPost;
+import org.briarproject.api.identity.Author;
+import org.briarproject.api.sync.Message;
+import org.briarproject.api.sync.MessageId;
+
+public class BlogPost extends ForumPost {
+
+	@Nullable
+	private final String title;
+	@NotNull
+	private final String teaser;
+	private final boolean hasBody;
+
+	public BlogPost(@Nullable String title, @NotNull String teaser,
+			boolean hasBody, @NotNull Message message,
+			@Nullable MessageId parent, @NotNull Author author,
+			@NotNull String contentType) {
+		super(message, parent, author, contentType);
+
+		this.title = title;
+		this.teaser = teaser;
+		this.hasBody = hasBody;
+	}
+
+	@Nullable
+	public String getTitle() {
+		return title;
+	}
+
+	@NotNull
+	public String getTeaser() {
+		return teaser;
+	}
+
+	public boolean hasBody() {
+		return hasBody;
+	}
+}

briar-api/src/org/briarproject/api/blogs/BlogPostFactory.java

@@ -0,0 +1,19 @@
+package org.briarproject.api.blogs;
+
+import org.briarproject.api.FormatException;
+import org.briarproject.api.identity.LocalAuthor;
+import org.briarproject.api.sync.GroupId;
+import org.briarproject.api.sync.MessageId;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.security.GeneralSecurityException;
+
+public interface BlogPostFactory {
+
+	BlogPost createBlogPost(@NotNull GroupId groupId, @Nullable String title,
+			@NotNull String teaser, long timestamp, @Nullable MessageId parent,
+			@NotNull LocalAuthor author, @NotNull String contentType,
+			@Nullable byte[] body)
+			throws FormatException, GeneralSecurityException;
+}

briar-api/src/org/briarproject/api/blogs/BlogPostHeader.java

@@ -0,0 +1,43 @@
+package org.briarproject.api.blogs;
+
+import org.briarproject.api.clients.PostHeader;
+import org.briarproject.api.identity.Author;
+import org.briarproject.api.identity.Author.Status;
+import org.briarproject.api.sync.MessageId;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+public class BlogPostHeader extends PostHeader {
+
+	@Nullable
+	private final String title;
+	@NotNull
+	private final String teaser;
+	private final boolean hasBody;
+
+	public BlogPostHeader(@Nullable String title, @NotNull String teaser,
+			boolean hasBody, @NotNull MessageId id,
+			@Nullable MessageId parentId, long timestamp,
+			@NotNull Author author,	@NotNull Status authorStatus,
+			@NotNull String contentType, boolean read) {
+		super(id, parentId, timestamp, author, authorStatus, contentType, read);
+
+		this.title = title;
+		this.teaser = teaser;
+		this.hasBody = hasBody;
+	}
+
+	@Nullable
+	public String getTitle() {
+		return title;
+	}
+
+	@NotNull
+	public String getTeaser() {
+		return teaser;
+	}
+
+	public boolean hasBody() {
+		return hasBody;
+	}
+}