diff --git a/src/Composer/Command/Command.php b/src/Composer/Command/Command.php
index 98298d139..227ee0479 100644
--- a/src/Composer/Command/Command.php
+++ b/src/Composer/Command/Command.php
@@ -12,6 +12,10 @@
 
 namespace Composer\Command;
 
+use Composer\Composer;
+use Composer\Console\Application;
+use Composer\IO\IOInterface;
+use Composer\IO\NullIO;
 use Symfony\Component\Console\Command\Command as BaseCommand;
 
 /**
@@ -23,18 +27,63 @@ use Symfony\Component\Console\Command\Command as BaseCommand;
 abstract class Command extends BaseCommand
 {
     /**
-     * @return \Composer\Composer
+     * @var \Composer\Composer
      */
-    protected function getComposer($required = true)
+    private $composer;
+
+    /**
+     * @var \Composer\IO\IOInterface
+     */
+    private $io;
+
+    /**
+     * @param   bool                $required
+     * @return  \Composer\Composer
+     */
+    public function getComposer($required = true)
     {
-        return $this->getApplication()->getComposer($required);
+        if (null === $this->composer) {
+            $application = $this->getApplication();
+            if ($application instanceof Application) {
+                /* @var $application    Application */
+                $this->composer = $application->getComposer();
+            }
+        }
+
+        return $this->composer;
     }
 
     /**
-     * @return \Composer\IO\ConsoleIO
+     * @param   \Composer\Composer  $composer
      */
-    protected function getIO()
+    public function setComposer(Composer $composer)
     {
-        return $this->getApplication()->getIO();
+        $this->composer = $composer;
+    }
+
+    /**
+     * @return \Composer\IO\IOInterface
+     */
+    public function getIO()
+    {
+        if (null === $this->io) {
+            $application = $this->getApplication();
+            if ($application instanceof Application) {
+                /* @var $application    Application */
+                $this->io = $application->getIO();
+            } else {
+                $this->io = new NullIO();
+            }
+        }
+
+        return $this->io;
+    }
+
+    /**
+     * @param   \Composer\IO\IOInterface    $io
+     */
+    public function setIO(IOInterface $io)
+    {
+        $this->io = $io;
     }
 }
diff --git a/src/Composer/Composer.php b/src/Composer/Composer.php
index 0ad14c450..61e0b0f7a 100644
--- a/src/Composer/Composer.php
+++ b/src/Composer/Composer.php
@@ -26,68 +26,128 @@ class Composer
 {
     const VERSION = '@package_version@';
 
+    /**
+     * @var Package\PackageInterface
+     */
     private $package;
+
+    /**
+     * @var Locker
+     */
     private $locker;
 
+    /**
+     * @var Repository\RepositoryManager
+     */
     private $repositoryManager;
+
+    /**
+     * @var Downloader\DownloadManager
+     */
     private $downloadManager;
+
+    /**
+     * @var Installer\InstallationManager
+     */
     private $installationManager;
 
+    /**
+     * @var Config
+     */
+    private $config;
+
+    /**
+     * @param   Package\PackageInterface    $package
+     * @return  void
+     */
     public function setPackage(PackageInterface $package)
     {
         $this->package = $package;
     }
 
+    /**
+     * @return  Package\PackageInterface
+     */
     public function getPackage()
     {
         return $this->package;
     }
 
+    /**
+     * @param   Config  $config
+     */
     public function setConfig(Config $config)
     {
         $this->config = $config;
     }
 
+    /**
+     * @return  Config
+     */
     public function getConfig()
     {
         return $this->config;
     }
 
+    /**
+     * @param   Package\Locker  $locker
+     */
     public function setLocker(Locker $locker)
     {
         $this->locker = $locker;
     }
 
+    /**
+     * @return  Package\Locker
+     */
     public function getLocker()
     {
         return $this->locker;
     }
 
+    /**
+     * @param   Repository\RepositoryManager    $manager
+     */
     public function setRepositoryManager(RepositoryManager $manager)
     {
         $this->repositoryManager = $manager;
     }
 
+    /**
+     * @return  Repository\RepositoryManager
+     */
     public function getRepositoryManager()
     {
         return $this->repositoryManager;
     }
 
+    /**
+     * @param   Downloader\DownloadManager  $manager
+     */
     public function setDownloadManager(DownloadManager $manager)
     {
         $this->downloadManager = $manager;
     }
 
+    /**
+     * @return  Doenloader\DownloadManager
+     */
     public function getDownloadManager()
     {
         return $this->downloadManager;
     }
 
+    /**
+     * @param   Installer\InstallationManager   $manager
+     */
     public function setInstallationManager(InstallationManager $manager)
     {
         $this->installationManager = $manager;
     }
 
+    /**
+     * @return  Installer\InstallationManager
+     */
     public function getInstallationManager()
     {
         return $this->installationManager;
diff --git a/src/Composer/Console/Application.php b/src/Composer/Console/Application.php
index 30f232acd..ea9712e41 100644
--- a/src/Composer/Console/Application.php
+++ b/src/Composer/Console/Application.php
@@ -35,7 +35,14 @@ use Composer\Util\ErrorHandler;
  */
 class Application extends BaseApplication
 {
+    /**
+     * @var Composer
+     */
     protected $composer;
+
+    /**
+     * @var ConsoleIO
+     */
     protected $io;
 
     public function __construct()
@@ -74,7 +81,8 @@ class Application extends BaseApplication
     }
 
     /**
-     * @return Composer
+     * @param   bool                $required
+     * @return  \Composer\Composer
      */
     public function getComposer($required = true)
     {
@@ -86,8 +94,6 @@ class Application extends BaseApplication
                     $this->io->write($e->getMessage());
                     exit(1);
                 }
-
-                return;
             }
         }
 
diff --git a/src/Composer/Factory.php b/src/Composer/Factory.php
index 0475a0688..721bfb6c9 100644
--- a/src/Composer/Factory.php
+++ b/src/Composer/Factory.php
@@ -70,9 +70,11 @@ class Factory
     /**
      * Creates a Composer instance
      *
-     * @param  IOInterface $io          IO instance
-     * @param  mixed       $localConfig either a configuration array or a filename to read from, if null it will read from the default filename
-     * @return Composer
+     * @param   IOInterface $io IO instance
+     * @param   array|string|null $localConfig either a configuration array or a filename to read from, if null it will
+     *          read from the default filename
+     * @throws  \InvalidArgumentException
+     * @return  Composer
      */
     public function createComposer(IOInterface $io, $localConfig = null)
     {
@@ -151,6 +153,11 @@ class Factory
         return $composer;
     }
 
+    /**
+     * @param   IO\IOInterface                  $io
+     * @param   Config                          $config
+     * @return  Repository\RepositoryManager
+     */
     protected function createRepositoryManager(IOInterface $io, Config $config)
     {
         $rm = new RepositoryManager($io, $config);
@@ -165,12 +172,20 @@ class Factory
         return $rm;
     }
 
+    /**
+     * @param   Repository\RepositoryManager $rm
+     * @param   string $vendorDir
+     */
     protected function addLocalRepository(RepositoryManager $rm, $vendorDir)
     {
         $rm->setLocalRepository(new Repository\InstalledFilesystemRepository(new JsonFile($vendorDir.'/composer/installed.json')));
         $rm->setLocalDevRepository(new Repository\InstalledFilesystemRepository(new JsonFile($vendorDir.'/composer/installed_dev.json')));
     }
 
+    /**
+     * @param   array   $localConfig
+     * @return  array
+     */
     protected function addPackagistRepository(array $localConfig)
     {
         $loadPackagist = true;
@@ -201,6 +216,10 @@ class Factory
         return $localConfig;
     }
 
+    /**
+     * @param   IO\IOInterface              $io
+     * @return  Downloader\DownloadManager
+     */
     public function createDownloadManager(IOInterface $io)
     {
         $dm = new Downloader\DownloadManager();
@@ -216,6 +235,14 @@ class Factory
         return $dm;
     }
 
+    /**
+     * @param   Repository\RepositoryManager    $rm
+     * @param   Downloader\DownloadManager      $dm
+     * @param   string                          $vendorDir
+     * @param   string                          $binDir
+     * @param   IO\IOInterface                  $io
+     * @return  Installer\InstallationManager
+     */
     protected function createInstallationManager(Repository\RepositoryManager $rm, Downloader\DownloadManager $dm, $vendorDir, $binDir, IOInterface $io)
     {
         $im = new Installer\InstallationManager($vendorDir);
@@ -226,9 +253,14 @@ class Factory
         return $im;
     }
 
+    /**
+     * @param   Repository\RepositoryManager    $rm
+     * @param   Installer\InstallationManager   $im
+     */
     protected function purgePackages(Repository\RepositoryManager $rm, Installer\InstallationManager $im)
     {
         foreach ($rm->getLocalRepositories() as $repo) {
+            /* @var $repo   Repository\WritableRepositoryInterface */
             foreach ($repo->getPackages() as $package) {
                 if (!$im->isPackageInstalled($repo, $package)) {
                     $repo->removePackage($package);
@@ -239,7 +271,8 @@ class Factory
 
     /**
      * @param  IOInterface $io     IO instance
-     * @param  mixed       $config either a configuration array or a filename to read from, if null it will read from the default filename
+     * @param  mixed       $config either a configuration array or a filename to read from, if null it will read from
+     *                             the default filename
      * @return Composer
      */
     public static function create(IOInterface $io, $config = null)
diff --git a/src/Composer/Repository/CompositeRepository.php b/src/Composer/Repository/CompositeRepository.php
index 53d3be821..ddfdf2810 100644
--- a/src/Composer/Repository/CompositeRepository.php
+++ b/src/Composer/Repository/CompositeRepository.php
@@ -105,6 +105,17 @@ class CompositeRepository implements RepositoryInterface
         return call_user_func_array('array_merge', $packages);
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function removePackage(PackageInterface $package)
+    {
+        foreach($this->repositories as $repository) {
+            /* @var $repository RepositoryInterface */
+            $repository->removePackage($package);
+        }
+    }
+
     /**
      * {@inheritdoc}
      */
diff --git a/src/Composer/Repository/RepositoryManager.php b/src/Composer/Repository/RepositoryManager.php
index 92738755a..cb4a616d8 100644
--- a/src/Composer/Repository/RepositoryManager.php
+++ b/src/Composer/Repository/RepositoryManager.php
@@ -166,7 +166,7 @@ class RepositoryManager
     /**
      * Returns all local repositories for the project.
      *
-     * @return array[RepositoryInterface]
+     * @return array[WritableRepositoryInterface]
      */
     public function getLocalRepositories()
     {