diff --git a/src/main/scala/app/WikiController.scala b/src/main/scala/app/WikiController.scala
index 1cf72ad..9cb6db7 100644
--- a/src/main/scala/app/WikiController.scala
+++ b/src/main/scala/app/WikiController.scala
@@ -1,10 +1,14 @@
 package app
 
-import util.{WikiUtil, JGitUtil}
+import service._
+import util.JGitUtil
+import util.Directory._
 import jp.sf.amateras.scalatra.forms._
 import org.eclipse.jgit.api.Git
 
-class WikiController extends ControllerBase {
+class WikiController extends WikiControllerBase with WikiService
+
+trait WikiControllerBase extends ControllerBase { self: WikiService =>
 
   case class WikiPageEditForm(pageName: String, content: String, message: Option[String], currentPageName: String)
   
@@ -26,7 +30,7 @@
     val owner      = params("owner")
     val repository = params("repository")
     
-    WikiUtil.getPage(owner, repository, "Home") match {
+    getWikiPage(owner, repository, "Home") match {
       case Some(page) => wiki.html.wiki("Home", page, 
         JGitUtil.getRepositoryInfo(owner, repository, servletContext))
       case None => wiki.html.wikiedit("Home", None, 
@@ -39,7 +43,7 @@
     val repository = params("repository")
     val pageName   = params("page")
     
-    WikiUtil.getPage(owner, repository, pageName) match {
+    getWikiPage(owner, repository, pageName) match {
       case Some(page) => wiki.html.wiki(pageName, page, 
         JGitUtil.getRepositoryInfo(owner, repository, servletContext))
       case None => wiki.html.wikiedit(pageName, None, 
@@ -52,7 +56,7 @@
     val repository = params("repository")
     val page       = params("page")
     
-    JGitUtil.withGit(WikiUtil.getWikiRepositoryDir(owner, repository)){ git =>
+    JGitUtil.withGit(getWikiRepositoryDir(owner, repository)){ git =>
       wiki.html.wikihistory(Some(page),
         JGitUtil.getCommitLog(git, "master", path = page + ".md")._1,
         JGitUtil.getRepositoryInfo(owner, repository, servletContext))
@@ -65,9 +69,9 @@
     val page       = params("page")
     val commitId   = params("commitId").split("\\.\\.\\.")
     
-    JGitUtil.withGit(WikiUtil.getWikiRepositoryDir(owner, repository)){ git =>
+    JGitUtil.withGit(getWikiRepositoryDir(owner, repository)){ git =>
       wiki.html.wikicompare(Some(page),
-        WikiUtil.getDiffs(git, commitId(0), commitId(1)),
+        getWikiDiffs(git, commitId(0), commitId(1)),
         JGitUtil.getRepositoryInfo(owner, repository, servletContext))
     }
   }
@@ -77,9 +81,9 @@
     val repository = params("repository")
     val commitId   = params("commitId").split("\\.\\.\\.")
     
-    JGitUtil.withGit(WikiUtil.getWikiRepositoryDir(owner, repository)){ git =>
+    JGitUtil.withGit(getWikiRepositoryDir(owner, repository)){ git =>
       wiki.html.wikicompare(None,
-        WikiUtil.getDiffs(git, commitId(0), commitId(1)),
+        getWikiDiffs(git, commitId(0), commitId(1)),
         JGitUtil.getRepositoryInfo(owner, repository, servletContext))
     }
   }
@@ -90,7 +94,7 @@
     val page       = params("page")
     
     wiki.html.wikiedit(page, 
-        WikiUtil.getPage(owner, repository, page), 
+        getWikiPage(owner, repository, page), 
         JGitUtil.getRepositoryInfo(owner, repository, servletContext))
   }
   
@@ -98,7 +102,7 @@
     val owner      = params("owner")
     val repository = params("repository")
     
-    WikiUtil.savePage(owner, repository, form.currentPageName, form.pageName, 
+    saveWikiPage(owner, repository, form.currentPageName, form.pageName, 
         form.content, context.loginUser, form.message.getOrElse(""))
     
     redirect("%s/%s/wiki/%s".format(owner, repository, form.pageName))
@@ -116,7 +120,7 @@
     val owner      = params("owner")
     val repository = params("repository")
     
-    WikiUtil.savePage(owner, repository, form.currentPageName, form.pageName, 
+    saveWikiPage(owner, repository, form.currentPageName, form.pageName, 
         form.content, context.loginUser, form.message.getOrElse(""))
     
     redirect("%s/%s/wiki/%s".format(owner, repository, form.pageName))
@@ -127,7 +131,7 @@
     val repository = params("repository")
     val page       = params("page")
     
-    WikiUtil.deletePage(owner, repository, page, context.loginUser, "Delete %s".format(page))
+    deleteWikiPage(owner, repository, page, context.loginUser, "Delete %s".format(page))
     
     redirect("%s/%s/wiki".format(owner, repository))
   }
@@ -136,7 +140,7 @@
     val owner      = params("owner")
     val repository = params("repository")
     
-    wiki.html.wikipages(WikiUtil.getPageList(owner, repository), 
+    wiki.html.wikipages(getWikiPageList(owner, repository), 
         JGitUtil.getRepositoryInfo(owner, repository, servletContext))
   }
   
@@ -144,7 +148,7 @@
     val owner      = params("owner")
     val repository = params("repository")
     
-    JGitUtil.withGit(WikiUtil.getWikiRepositoryDir(owner, repository)){ git =>
+    JGitUtil.withGit(getWikiRepositoryDir(owner, repository)){ git =>
       wiki.html.wikihistory(None,
         JGitUtil.getCommitLog(git, "master")._1, 
         JGitUtil.getRepositoryInfo(owner, repository, servletContext))
@@ -174,7 +178,7 @@
   
   def unique: Constraint = new Constraint(){
     def validate(name: String, value: String): Option[String] = {
-      if(WikiUtil.getPageList(params("owner"), params("repository")).contains(value)){
+      if(getWikiPageList(params("owner"), params("repository")).contains(value)){
         Some("Page already exists.")
       } else {
         None
diff --git a/src/main/scala/service/WikiService.scala b/src/main/scala/service/WikiService.scala
new file mode 100644
index 0000000..f356f39
--- /dev/null
+++ b/src/main/scala/service/WikiService.scala
@@ -0,0 +1,191 @@
+package service
+
+import java.io.File
+import java.util.Date
+import org.eclipse.jgit.api.Git
+import org.apache.commons.io.FileUtils
+import app.DiffInfo
+import util.{Directory, JGitUtil}
+import org.eclipse.jgit.lib.RepositoryBuilder
+import org.eclipse.jgit.treewalk.CanonicalTreeParser
+import org.eclipse.jgit.treewalk.TreeWalk
+import org.eclipse.jgit.revwalk.RevCommit
+import org.eclipse.jgit.revwalk.RevWalk
+import org.eclipse.jgit.diff.DiffEntry.ChangeType
+
+object WikiService {
+  
+  /**
+   * The model for wiki page.
+   * 
+   * @param name the page name
+   * @param content the page content
+   * @param committer the last committer
+   * @param time the last modified time
+   */
+  case class WikiPageInfo(name: String, content: String, committer: String, time: Date)
+  
+  /**
+   * The model for wiki page history.
+   * 
+   * @param name the page name
+   * @param committer the committer the committer
+   * @param message the commit message
+   * @param date the commit date
+   */
+  case class WikiPageHistoryInfo(name: String, committer: String, message: String, date: Date)
+  
+}
+
+trait WikiService {
+  
+  import WikiService._
+  
+//  /**
+//   * Returns the directory of the wiki repository.
+//   */
+//  def getWikiRepositoryDir(owner: String, repository: String): File =
+//    new File("%s/%s/%s.wiki.git".format(Directory.RepositoryHome, owner, repository))
+//  
+//  /**
+//   * Returns the directory of the wiki working directory which is cloned from the wiki repository.
+//   */
+//  def getWikiWorkDir(owner: String, repository: String): File = 
+//    new File("%s/tmp/%s/%s.wiki".format(Directory.GitBucketHome, owner, repository))
+
+  // TODO synchronized?
+  def createWikiRepository(owner: String, repository: String): Unit = {
+    val dir = Directory.getWikiRepositoryDir(owner, repository)
+    if(!dir.exists){
+      val repo = new RepositoryBuilder().setGitDir(dir).setBare.build
+      try {
+        repo.create
+        saveWikiPage(owner, repository, "Home", "Home", "Welcome to the %s wiki!!".format(repository), owner, "Initial Commit")
+      } finally {
+        repo.close
+      }
+    }
+  }
+  
+  /**
+   * Returns the wiki page.
+   */
+  def getWikiPage(owner: String, repository: String, pageName: String): Option[WikiPageInfo] = {
+    // TODO create wiki repository in the repository setting changing.
+    createWikiRepository(owner, repository)
+    
+    JGitUtil.withGit(Directory.getWikiRepositoryDir(owner, repository)){ git =>
+      try {
+        JGitUtil.getFileList(git, "master", ".").find(_.name == pageName + ".md").map { file =>
+          WikiPageInfo(file.name, new String(git.getRepository.open(file.id).getBytes, "UTF-8"), file.committer, file.time)
+        }
+      } catch {
+        // TODO no commit, but it should not judge by exception.
+        case e: NullPointerException => None
+      }
+    }
+  }
+  
+  def getWikiPageList(owner: String, repository: String): List[String] = {
+    JGitUtil.getFileList(Git.open(Directory.getWikiRepositoryDir(owner, repository)), "master", ".")
+      .filter(_.name.endsWith(".md"))
+      .map(_.name.replaceFirst("\\.md$", ""))
+      .sortBy(x => x)
+  }
+  
+  // TODO synchronized
+  /**
+   * Save the wiki page.
+   */
+  def saveWikiPage(owner: String, repository: String, currentPageName: String, newPageName: String,
+      content: String, committer: String, message: String): Unit = {
+    
+    // TODO create wiki repository in the repository setting changing.
+    createWikiRepository(owner, repository)
+    
+    val workDir = Directory.getWikiWorkDir(owner, repository)
+    
+    // clone
+    if(!workDir.exists){
+      Git.cloneRepository
+        .setURI(Directory.getWikiRepositoryDir(owner, repository).toURI.toString)
+        .setDirectory(workDir)
+        .call
+    }
+    
+    // write as file
+    JGitUtil.withGit(workDir){ git =>
+      val file = new File(workDir, newPageName + ".md")
+      val added = if(!file.exists || FileUtils.readFileToString(file, "UTF-8") != content){
+        FileUtils.writeStringToFile(file, content, "UTF-8")
+        git.add.addFilepattern(file.getName).call
+        true
+      } else {
+        false
+      }
+    
+      // delete file
+      val deleted = if(currentPageName != "" && currentPageName != newPageName){
+        git.rm.addFilepattern(currentPageName + ".md").call
+        true
+      } else {
+        false
+      }
+    
+      // commit and push
+      if(added || deleted){
+        // TODO committer's mail address
+        git.commit.setAuthor(committer, committer + "@devnull").setMessage(message).call
+        git.push.call
+      }
+    }
+  }
+  
+  /**
+   * Delete the wiki page.
+   */
+  def deleteWikiPage(owner: String, repository: String, pageName: String, committer: String, message: String): Unit = {
+    // TODO create wiki repository in the repository setting changing.
+    createWikiRepository(owner, repository)
+    
+    val workDir = Directory.getWikiWorkDir(owner, repository)
+    
+    // clone
+    if(!workDir.exists){
+      Git.cloneRepository
+        .setURI(Directory.getWikiRepositoryDir(owner, repository).toURI.toString)
+        .setDirectory(workDir)
+        .call
+    }
+    
+    // delete file
+    new File(workDir, pageName + ".md").delete
+    
+    JGitUtil.withGit(workDir){ git =>
+      git.rm.addFilepattern(pageName + ".md").call
+    
+      // commit and push
+      // TODO committer's mail address
+      git.commit.setAuthor(committer, committer + "@devnull").setMessage(message).call
+      git.push.call
+    }
+  }
+  
+  def getWikiDiffs(git: Git, commitId1: String, commitId2: String): List[DiffInfo] = {
+      // get diff between specified commit and its previous commit
+      val reader = git.getRepository.newObjectReader
+      
+      val oldTreeIter = new CanonicalTreeParser
+      oldTreeIter.reset(reader, git.getRepository.resolve(commitId1 + "^{tree}"))
+      
+      val newTreeIter = new CanonicalTreeParser
+      newTreeIter.reset(reader, git.getRepository.resolve(commitId2 + "^{tree}"))
+      
+      import scala.collection.JavaConverters._
+      git.diff.setNewTree(newTreeIter).setOldTree(oldTreeIter).call.asScala.map { diff =>
+        DiffInfo(diff.getChangeType, diff.getOldPath, diff.getNewPath,
+            JGitUtil.getContent(git, diff.getOldId.toObjectId, false).map(new String(_, "UTF-8")), 
+            JGitUtil.getContent(git, diff.getNewId.toObjectId, false).map(new String(_, "UTF-8")))
+      }.toList
+  }   
+}
diff --git a/src/main/scala/util/Directory.scala b/src/main/scala/util/Directory.scala
index 6bfed55..96dcddb 100644
--- a/src/main/scala/util/Directory.scala
+++ b/src/main/scala/util/Directory.scala
@@ -47,4 +47,16 @@
   def getInitRepositoryDir(owner: String, repository: String): File =
     new File("%s/tmp/%s/init-%s".format(GitBucketHome, owner, repository))
   
+  /**
+   * Substance directory of the wiki repository.
+   */
+  def getWikiRepositoryDir(owner: String, repository: String): File =
+    new File("%s/%s/%s.wiki.git".format(Directory.RepositoryHome, owner, repository))
+  
+  /**
+   * Wiki working directory which is cloned from the wiki repository.
+   */
+  def getWikiWorkDir(owner: String, repository: String): File = 
+    new File("%s/tmp/%s/%s.wiki".format(Directory.GitBucketHome, owner, repository))
+  
 }
\ No newline at end of file
diff --git a/src/main/scala/util/WikiUtil.scala b/src/main/scala/util/WikiUtil.scala
deleted file mode 100644
index c91fff0..0000000
--- a/src/main/scala/util/WikiUtil.scala
+++ /dev/null
@@ -1,179 +0,0 @@
-package util
-
-import java.io.File
-import java.util.Date
-import org.eclipse.jgit.api.Git
-import org.apache.commons.io.FileUtils
-import org.eclipse.jgit.lib.RepositoryBuilder
-import app.DiffInfo
-import org.eclipse.jgit.treewalk.CanonicalTreeParser
-import org.eclipse.jgit.revwalk.RevCommit
-import org.eclipse.jgit.treewalk.TreeWalk
-import org.eclipse.jgit.revwalk.RevWalk
-import org.eclipse.jgit.diff.DiffEntry.ChangeType
-
-object WikiUtil {
-  
-  /**
-   * The model for wiki page.
-   * 
-   * @param name the page name
-   * @param content the page content
-   * @param committer the last committer
-   * @param time the last modified time
-   */
-  case class WikiPageInfo(name: String, content: String, committer: String, time: Date)
-  
-  /**
-   * The model for wiki page history.
-   * 
-   * @param name the page name
-   * @param committer the committer the committer
-   * @param message the commit message
-   * @param date the commit date
-   */
-  case class WikiPageHistoryInfo(name: String, committer: String, message: String, date: Date)
-  
-  /**
-   * Returns the directory of the wiki repository.
-   */
-  def getWikiRepositoryDir(owner: String, repository: String): File =
-    new File("%s/%s/%s.wiki.git".format(Directory.RepositoryHome, owner, repository))
-  
-  /**
-   * Returns the directory of the wiki working directory which is cloned from the wiki repository.
-   */
-  def getWikiWorkDir(owner: String, repository: String): File = 
-    new File("%s/tmp/%s/%s.wiki".format(Directory.GitBucketHome, owner, repository))
-
-  // TODO synchronized?
-  def createWikiRepository(owner: String, repository: String): Unit = {
-    val dir = getWikiRepositoryDir(owner, repository)
-    if(!dir.exists){
-      val repo = new RepositoryBuilder().setGitDir(dir).setBare.build
-      try {
-        repo.create
-        savePage(owner, repository, "Home", "Home", "Welcome to the %s wiki!!".format(repository), owner, "Initial Commit")
-      } finally {
-        repo.close
-      }
-    }
-  }
-  
-  /**
-   * Returns the wiki page.
-   */
-  def getPage(owner: String, repository: String, pageName: String): Option[WikiPageInfo] = {
-    // TODO create wiki repository in the repository setting changing.
-    createWikiRepository(owner, repository)
-    
-    JGitUtil.withGit(getWikiRepositoryDir(owner, repository)){ git =>
-      try {
-        JGitUtil.getFileList(git, "master", ".").find(_.name == pageName + ".md").map { file =>
-          WikiPageInfo(file.name, new String(git.getRepository.open(file.id).getBytes, "UTF-8"), file.committer, file.time)
-        }
-      } catch {
-        // TODO no commit, but it should not judge by exception.
-        case e: NullPointerException => None
-      }
-    }
-  }
-  
-  def getPageList(owner: String, repository: String): List[String] = {
-    JGitUtil.getFileList(Git.open(getWikiRepositoryDir(owner, repository)), "master", ".")
-      .filter(_.name.endsWith(".md"))
-      .map(_.name.replaceFirst("\\.md$", ""))
-      .sortBy(x => x)
-  }
-  
-  // TODO synchronized
-  /**
-   * Save the wiki page.
-   */
-  def savePage(owner: String, repository: String, currentPageName: String, newPageName: String,
-      content: String, committer: String, message: String): Unit = {
-    
-    // TODO create wiki repository in the repository setting changing.
-    createWikiRepository(owner, repository)
-    
-    val workDir = getWikiWorkDir(owner, repository)
-    
-    // clone
-    if(!workDir.exists){
-      Git.cloneRepository.setURI(getWikiRepositoryDir(owner, repository).toURI.toString).setDirectory(workDir).call
-    }
-    
-    // write as file
-    JGitUtil.withGit(workDir){ git =>
-      val file = new File(workDir, newPageName + ".md")
-      val added = if(!file.exists || FileUtils.readFileToString(file, "UTF-8") != content){
-        FileUtils.writeStringToFile(file, content, "UTF-8")
-        git.add.addFilepattern(file.getName).call
-        true
-      } else {
-        false
-      }
-    
-      // delete file
-      val deleted = if(currentPageName != "" && currentPageName != newPageName){
-        git.rm.addFilepattern(currentPageName + ".md").call
-        true
-      } else {
-        false
-      }
-    
-      // commit and push
-      if(added || deleted){
-        // TODO committer's mail address
-        git.commit.setAuthor(committer, committer + "@devnull").setMessage(message).call
-        git.push.call
-      }
-    }
-  }
-  
-  /**
-   * Delete the wiki page.
-   */
-  def deletePage(owner: String, repository: String, pageName: String, committer: String, message: String): Unit = {
-    // TODO create wiki repository in the repository setting changing.
-    createWikiRepository(owner, repository)
-    
-    val workDir = getWikiWorkDir(owner, repository)
-    
-    // clone
-    if(!workDir.exists){
-      Git.cloneRepository.setURI(getWikiRepositoryDir(owner, repository).toURI.toString).setDirectory(workDir).call
-    }
-    
-    // delete file
-    new File(workDir, pageName + ".md").delete
-    
-    JGitUtil.withGit(workDir){ git =>
-      git.rm.addFilepattern(pageName + ".md").call
-    
-      // commit and push
-      // TODO committer's mail address
-      git.commit.setAuthor(committer, committer + "@devnull").setMessage(message).call
-      git.push.call
-    }
-  }
-  
-  def getDiffs(git: Git, commitId1: String, commitId2: String): List[DiffInfo] = {
-      // get diff between specified commit and its previous commit
-      val reader = git.getRepository.newObjectReader
-      
-      val oldTreeIter = new CanonicalTreeParser
-      oldTreeIter.reset(reader, git.getRepository.resolve(commitId1 + "^{tree}"))
-      
-      val newTreeIter = new CanonicalTreeParser
-      newTreeIter.reset(reader, git.getRepository.resolve(commitId2 + "^{tree}"))
-      
-      import scala.collection.JavaConverters._
-      git.diff.setNewTree(newTreeIter).setOldTree(oldTreeIter).call.asScala.map { diff =>
-        DiffInfo(diff.getChangeType, diff.getOldPath, diff.getNewPath,
-            JGitUtil.getContent(git, diff.getOldId.toObjectId, false).map(new String(_, "UTF-8")), 
-            JGitUtil.getContent(git, diff.getNewId.toObjectId, false).map(new String(_, "UTF-8")))
-      }.toList
-  }    
-  
-}
\ No newline at end of file
diff --git a/src/main/twirl/wiki/wiki.scala.html b/src/main/twirl/wiki/wiki.scala.html
index f5c0f5e..2c9ab3d 100644
--- a/src/main/twirl/wiki/wiki.scala.html
+++ b/src/main/twirl/wiki/wiki.scala.html
@@ -1,4 +1,4 @@
-@(pageName: String, page: util.WikiUtil.WikiPageInfo, repository: app.RepositoryInfo)(implicit context: app.Context)
+@(pageName: String, page: service.WikiService.WikiPageInfo, repository: app.RepositoryInfo)(implicit context: app.Context)
 @import view.helpers
 @import context._
 @html.main(pageName + " - " + repository.owner + "/" + repository.name){
diff --git a/src/main/twirl/wiki/wikiedit.scala.html b/src/main/twirl/wiki/wikiedit.scala.html
index de5c140..771c8af 100644
--- a/src/main/twirl/wiki/wikiedit.scala.html
+++ b/src/main/twirl/wiki/wikiedit.scala.html
@@ -1,4 +1,4 @@
-@(pageName: String, page: Option[util.WikiUtil.WikiPageInfo], repository: app.RepositoryInfo)(implicit context: app.Context)
+@(pageName: String, page: Option[service.WikiService.WikiPageInfo], repository: app.RepositoryInfo)(implicit context: app.Context)
 @import view.helpers
 @import context._
 @html.main((if(pageName == "") "New Page" else pageName) + " - " + repository.owner + "/" + repository.name){