diff --git a/src/main/scala/app/RepositoryViewerServlet.scala b/src/main/scala/app/RepositoryViewerServlet.scala
index dd44cdc..f9b4c81 100644
--- a/src/main/scala/app/RepositoryViewerServlet.scala
+++ b/src/main/scala/app/RepositoryViewerServlet.scala
@@ -20,6 +20,9 @@
  */
 class RepositoryViewerServlet extends ScalatraServlet with ServletBase {
   
+  /**
+   * Shows user information.
+   */
   get("/:owner") {
     val owner = params("owner")
     html.user.render(owner, getRepositories(owner).map(getRepositoryInfo(owner, _)))
@@ -109,7 +112,13 @@
       CommitInfo(latestRev.getName, latestRev.getCommitterIdent.getWhen, latestRev.getCommitterIdent.getName, latestRev.getShortMessage))
   }
   
-  def getRepositoryInfo(owner: String, repository: String) = {
+  /**
+   * Returns the repository information. It contains branch names and tag names.
+   * 
+   * @param owner the repository owner
+   * @param repository the repository name
+   */
+  def getRepositoryInfo(owner: String, repository: String): RepositoryInfo = {
     val git = Git.open(getRepositoryDir(owner, repository))
     RepositoryInfo(
       owner, repository, "http://localhost:8080/git/%s/%s.git".format(owner, repository),
@@ -127,8 +136,13 @@
   /**
    * Setup all branches for the repository viewer.
    * This method copies the repository and checkout branches.
+   * 
+   * TODO Should it be a repository update hook?
+   * 
+   * @param owner the repository owner
+   * @param repository the repository name
    */
-  def updateAllBranches(owner: String, repository: String) = {
+  def updateAllBranches(owner: String, repository: String): Unit = {
     val dir = getRepositoryDir(owner, repository)
     val git = Git.open(dir)
     
@@ -154,7 +168,13 @@
   }
   
   /**
-   * Provides the file list of the specified branch and path.
+   * Provides HTML of the file list.
+   * 
+   * @param owner the repository owner
+   * @param repository the repository name
+   * @param branch the branch name (optional)
+   * @param path the directory path (optional)
+   * @return HTML of the file list
    */
   def fileList(owner: String, repository: String, branch: String = "", path: String = ".") = {
     val branchName = if(branch.isEmpty){
diff --git a/src/main/scala/util/Directory.scala b/src/main/scala/util/Directory.scala
index 5f80f72..8a90349 100644
--- a/src/main/scala/util/Directory.scala
+++ b/src/main/scala/util/Directory.scala
@@ -2,20 +2,37 @@
 
 import java.io.File
 
+/**
+ * Provides directories used by GitBucket.
+ */
 object Directory {
 
   val GitBucketHome = new File(System.getProperty("user.home"), "gitbucket").getAbsolutePath
-    
+  
+  /**
+   * Repository names of the specified user.
+   */
   def getRepositories(owner: String): List[String] =
     new File("%s/repositories/%s".format(GitBucketHome, owner))
       .listFiles.filter(_.isDirectory).map(_.getName.replaceFirst("\\.git$", "")).toList
-    
+  
+  /**
+   * Substance directory of the repository.
+   */
   def getRepositoryDir(owner: String, repository: String): File =
     new File("%s/repositories/%s/%s.git".format(GitBucketHome, owner, repository))
   
+  /**
+   * Temporary directory which is used in the repository viewer.
+   */
   def getBranchDir(owner: String, repository: String, branch: String): File =
     new File("%s/tmp/%s/branches/%s/%s".format(GitBucketHome, owner, repository, branch))
   
+  /**
+   * Temporary directory which is used in the repository creation.
+   * GiyBucket generates initial repository contents in this directory and push them.
+   * This directory is removed after the repository creation.
+   */
   def getInitRepositoryDir(owner: String, repository: String): File =
     new File("%s/tmp/%s/init-%s".format(GitBucketHome, owner, repository))
 
diff --git a/src/main/scala/util/Implicits.scala b/src/main/scala/util/Implicits.scala
index dbf60d9..2d044e6 100644
--- a/src/main/scala/util/Implicits.scala
+++ b/src/main/scala/util/Implicits.scala
@@ -1,6 +1,10 @@
 package util
 
+/**
+ * Provides some usable implicit conversions.
+ */
 object Implicits {
+  
   implicit def extendsSeq[A](seq: Seq[A]) = new {
 
     def splitWith(condition: (A, A) => Boolean): Seq[Seq[A]] = split(seq)(condition)