diff --git a/src/Grant/AbstractGrant.php b/src/Grant/AbstractGrant.php
index fd5cb52f..3734f91a 100644
--- a/src/Grant/AbstractGrant.php
+++ b/src/Grant/AbstractGrant.php
@@ -11,10 +11,13 @@
 
 namespace League\OAuth2\Server\Grant;
 
-use League\OAuth2\Server\AuthorizationServer;
-use League\OAuth2\Server\Entity\ClientEntity;
-use League\OAuth2\Server\Entity\ScopeEntity;
+use League\Event\Emitter;
+use League\OAuth2\Server\Entities\Interfaces\ClientEntityInterface;
+use League\OAuth2\Server\Entities\ScopeEntity;
 use League\OAuth2\Server\Exception;
+use League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface;
+use League\OAuth2\Server\Repositories\ClientRepositoryInterface;
+use League\OAuth2\Server\Repositories\ScopeRepositoryInterface;
 
 /**
  * Abstract grant class
@@ -29,32 +32,54 @@ abstract class AbstractGrant implements GrantTypeInterface
     protected $identifier = '';
 
     /**
-     * Response type
+     * Grant responds with
      *
      * @var string
      */
-    protected $responseType;
+    protected $respondsWith = 'token';
 
     /**
-     * Callback to authenticate a user's name and password
-     *
-     * @var callable
+     * @var \Symfony\Component\HttpFoundation\Request
      */
-    protected $callback;
+    protected $request;
 
     /**
-     * AuthServer instance
-     *
-     * @var \League\OAuth2\Server\AuthorizationServer
+     * @var ClientRepositoryInterface
      */
-    protected $server;
+    protected $clientRepository;
 
     /**
-     * Access token expires in override
-     *
-     * @var int
+     * @var AccessTokenRepositoryInterface
      */
-    protected $accessTokenTTL;
+    protected $accessTokenRepository;
+
+    /**
+     * @var \League\Event\Emitter
+     */
+    protected $emitter;
+
+    /**
+     * @var ScopeRepositoryInterface
+     */
+    protected $scopeRepository;
+
+    /**
+     * @param \League\Event\Emitter                                             $emitter
+     * @param \League\OAuth2\Server\Repositories\ClientRepositoryInterface      $clientRepository
+     * @param \League\OAuth2\Server\Repositories\ScopeRepositoryInterface       $scopeRepository
+     * @param \League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface $accessTokenRepository
+     */
+    public function __construct(
+        Emitter $emitter,
+        ClientRepositoryInterface $clientRepository,
+        ScopeRepositoryInterface $scopeRepository,
+        AccessTokenRepositoryInterface $accessTokenRepository
+    ) {
+        $this->emitter = $emitter;
+        $this->clientRepository = $clientRepository;
+        $this->scopeRepository = $scopeRepository;
+        $this->accessTokenRepository = $accessTokenRepository;
+    }
 
     /**
      * {@inheritdoc}
@@ -67,74 +92,27 @@ abstract class AbstractGrant implements GrantTypeInterface
     /**
      * {@inheritdoc}
      */
-    public function setIdentifier($identifier)
+    public function respondsWith()
     {
-        $this->identifier = $identifier;
-
-        return $this;
+        return $this->respondsWith;
     }
 
     /**
-     * {@inheritdoc}
+     * @param string                $scopeParamValue A string containing a delimited set of scope identifiers
+     * @param string                $scopeDelimiter  The delimiter between the scopes in the value string
+     * @param ClientEntityInterface $client
+     * @param string                $redirectUri
+     *
+     * @return \League\OAuth2\Server\Entities\ScopeEntity[]
+     * @throws \League\OAuth2\Server\Exception\InvalidScopeException
      */
-    public function getResponseType()
-    {
-        return $this->responseType;
-    }
-
-    /**
-     * Get the TTL for an access token
-     *
-     * @return int The TTL
-     */
-    public function getAccessTokenTTL()
-    {
-        if ($this->accessTokenTTL) {
-            return $this->accessTokenTTL;
-        }
-
-        return $this->server->getAccessTokenTTL();
-    }
-
-    /**
-     * Override the default access token expire time
-     *
-     * @param int $accessTokenTTL
-     *
-     * @return self
-     */
-    public function setAccessTokenTTL($accessTokenTTL)
-    {
-        $this->accessTokenTTL = $accessTokenTTL;
-
-        return $this;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function setAuthorizationServer(AuthorizationServer $server)
-    {
-        $this->server = $server;
-
-        return $this;
-    }
-
-    /**
-     * Given a list of scopes, validate them and return an array of Scope entities
-     *
-     * @param string                                    $scopeParam  A string of scopes (e.g. "profile email birthday")
-     * @param \League\OAuth2\Server\Entity\ClientEntity $client      Client entity
-     * @param string|null                               $redirectUri The redirect URI to return the user to
-     *
-     * @return \League\OAuth2\Server\Entity\ScopeEntity[]
-     *
-     * @throws \League\OAuth2\Server\Exception\InvalidScopeException If scope is invalid, or no scopes passed when required
-     * @throws
-     */
-    public function validateScopes($scopeParam = '', ClientEntity $client, $redirectUri = null)
-    {
-        $scopesList = explode($this->server->getScopeDelimiter(), $scopeParam);
+    public function validateScopes(
+        $scopeParamValue,
+        $scopeDelimiter,
+        ClientEntityInterface $client,
+        $redirectUri = null
+    ) {
+        $scopesList = explode($scopeDelimiter, trim($scopeParamValue));
 
         for ($i = 0; $i < count($scopesList); $i++) {
             $scopesList[$i] = trim($scopesList[$i]);
@@ -143,53 +121,19 @@ abstract class AbstractGrant implements GrantTypeInterface
             }
         }
 
-        if (
-            $this->server->scopeParamRequired() === true
-            && $this->server->getDefaultScope() === null
-            && count($scopesList) === 0
-        ) {
-            throw new Exception\InvalidRequestException('scope');
-        } elseif (count($scopesList) === 0 && $this->server->getDefaultScope() !== null) {
-            if (is_array($this->server->getDefaultScope())) {
-                $scopesList = $this->server->getDefaultScope();
-            } else {
-                $scopesList = [0 => $this->server->getDefaultScope()];
-            }
-        }
-
         $scopes = [];
-
         foreach ($scopesList as $scopeItem) {
-            $scope = $this->server->getScopeStorage()->get(
+            $scope = $this->scopeRepository->get(
                 $scopeItem,
                 $this->getIdentifier(),
-                $client->getId()
+                $client->getIdentifier()
             );
 
             if (($scope instanceof ScopeEntity) === false) {
                 throw new Exception\InvalidScopeException($scopeItem, $redirectUri);
             }
 
-            $scopes[$scope->getId()] = $scope;
-        }
-
-        return $scopes;
-    }
-
-    /**
-     * Format the local scopes array
-     *
-     * @param  \League\OAuth2\Server\Entity\ScopeEntity[]
-     *
-     * @return array
-     */
-    protected function formatScopes($unformated = [])
-    {
-        $scopes = [];
-        foreach ($unformated as $scope) {
-            if ($scope instanceof ScopeEntity) {
-                $scopes[$scope->getId()] = $scope;
-            }
+            $scopes[] = $scope;
         }
 
         return $scopes;
diff --git a/src/Grant/ClientCredentialsGrant.php b/src/Grant/ClientCredentialsGrant.php
index e219c633..f875143d 100644
--- a/src/Grant/ClientCredentialsGrant.php
+++ b/src/Grant/ClientCredentialsGrant.php
@@ -11,12 +11,14 @@
 
 namespace League\OAuth2\Server\Grant;
 
-use League\OAuth2\Server\Entity\AccessTokenEntity;
-use League\OAuth2\Server\Entity\ClientEntity;
-use League\OAuth2\Server\Entity\SessionEntity;
-use League\OAuth2\Server\Event;
+use DateInterval;
+use League\Event\Event;
+use League\OAuth2\Server\Entities\AccessTokenEntity;
+use League\OAuth2\Server\Entities\Interfaces\ClientEntityInterface;
 use League\OAuth2\Server\Exception;
-use League\OAuth2\Server\Util\SecureKey;
+use League\OAuth2\Server\ResponseTypes\ResponseTypeInterface;
+use League\OAuth2\Server\Utils\SecureKey;
+use Symfony\Component\HttpFoundation\Request;
 
 /**
  * Client credentials grant class
@@ -31,92 +33,70 @@ class ClientCredentialsGrant extends AbstractGrant
     protected $identifier = 'client_credentials';
 
     /**
-     * Response type
+     * Return an access token
      *
-     * @var string
+     * @param \Symfony\Component\HttpFoundation\Request                 $request
+     * @param \League\OAuth2\Server\ResponseTypes\ResponseTypeInterface $responseType
+     * @param \DateInterval                                             $accessTokenTTL
+     * @param string                                                    $scopeDelimiter
+     *
+     * @return \League\OAuth2\Server\ResponseTypes\ResponseTypeInterface
+     * @throws \League\OAuth2\Server\Exception\InvalidClientException
+     * @throws \League\OAuth2\Server\Exception\InvalidRequestException
+     * @throws \League\OAuth2\Server\Exception\InvalidScopeException
      */
-    protected $responseType = null;
-
-    /**
-     * AuthServer instance
-     *
-     * @var \League\OAuth2\Server\AuthorizationServer
-     */
-    protected $server = null;
-
-    /**
-     * Access token expires in override
-     *
-     * @var int
-     */
-    protected $accessTokenTTL = null;
-
-    /**
-     * Complete the client credentials grant
-     *
-     * @return array
-     *
-     * @throws
-     */
-    public function completeFlow()
-    {
+    public function getAccessTokenAsType(
+        Request $request,
+        ResponseTypeInterface $responseType,
+        DateInterval $accessTokenTTL,
+        $scopeDelimiter = ' '
+    ) {
         // Get the required params
-        $clientId = $this->server->getRequest()->request->get('client_id', $this->server->getRequest()->getUser());
+        $clientId = $request->request->get('client_id', $request->getUser());
         if (is_null($clientId)) {
             throw new Exception\InvalidRequestException('client_id');
         }
 
-        $clientSecret = $this->server->getRequest()->request->get('client_secret',
-            $this->server->getRequest()->getPassword());
+        $clientSecret = $request->request->get('client_secret', $request->getPassword());
         if (is_null($clientSecret)) {
             throw new Exception\InvalidRequestException('client_secret');
         }
 
         // Validate client ID and client secret
-        $client = $this->server->getClientStorage()->get(
+        $client = $this->clientRepository->get(
             $clientId,
             $clientSecret,
             null,
             $this->getIdentifier()
         );
 
-        if (($client instanceof ClientEntity) === false) {
-            $this->server->getEventEmitter()->emit(new Event\ClientAuthenticationFailedEvent($this->server->getRequest()));
+        if (($client instanceof ClientEntityInterface) === false) {
+            $this->emitter->emit(new Event('client.authentication.failed', $request));
             throw new Exception\InvalidClientException();
         }
 
         // Validate any scopes that are in the request
-        $scopeParam = $this->server->getRequest()->request->get('scope', '');
-        $scopes = $this->validateScopes($scopeParam, $client);
-
-        // Create a new session
-        $session = new SessionEntity($this->server);
-        $session->setOwner('client', $client->getId());
-        $session->associateClient($client);
+        $scopeParam = $request->request->get('scope', '');
+        $scopes = $this->validateScopes($scopeParam, $scopeDelimiter, $client);
 
         // Generate an access token
-        $accessToken = new AccessTokenEntity($this->server);
-        $accessToken->setId(SecureKey::generate());
-        $accessToken->setExpireTime($this->getAccessTokenTTL() + time());
+        $accessToken = new AccessTokenEntity();
+        $accessToken->setIdentifier(SecureKey::generate());
+        $accessToken->setExpiryDateTime((new \DateTime())->add($accessTokenTTL));
+        $accessToken->setClient($client);
+        $accessToken->setOwner('client', $client->getIdentifier());
 
         // Associate scopes with the session and access token
         foreach ($scopes as $scope) {
-            $session->associateScope($scope);
+            $accessToken->addScope($scope);
         }
 
-        foreach ($session->getScopes() as $scope) {
-            $accessToken->associateScope($scope);
-        }
+        // Save the token
+        $this->accessTokenRepository->create($accessToken);
 
-        // Save everything
-        $session->save();
-        $accessToken->setSession($session);
-        $accessToken->save();
+        // Inject access token into token type
+        $responseType->setAccessToken($accessToken);
 
-        $this->server->getTokenType()->setSession($session);
-        $this->server->getTokenType()->setParam('access_token', $accessToken->getId());
-        $this->server->getTokenType()->setParam('expires_in', $this->getAccessTokenTTL());
-
-        return $this->server->getTokenType()->generateResponse();
+        return $responseType;
     }
 }