add OCAccount

add OCAccount

src/com/owncloud/android/lib/refactor/OCContext.java

@@ -2,6 +2,7 @@ package com.owncloud.android.lib.refactor;
 
 import android.net.Uri;
 
+import com.owncloud.android.lib.refactor.account.OCAccount;
 import com.owncloud.android.lib.refactor.authentication.OCCredentials;
 
 
@@ -18,33 +19,13 @@ public class OCContext {
     private static final boolean PARAM_SINGLE_COOKIE_HEADER_VALUE = true;
     private static final String PARAM_PROTOCOL_VERSION = "http.protocol.version";
 
-    private OCCredentials mCredentials = null;
+    private OCAccount mOCAccount;
-    private Uri mBaseUri;
 
-    public class Builder {
+    public OCContext(OCAccount account) {
-        OCContext ocContext = new OCContext();
+        mOCAccount = account;
-
-        public Builder setCredentials(OCCredentials credentials) {
-            ocContext.mCredentials = credentials;
-            return this;
-        }
-
-        public Builder setBaseUri(Uri baseUri) {
-            ocContext.mBaseUri = baseUri;
-            return this;
-        }
-
-        public OCContext build() {
-            return ocContext;
-        }
     }
 
-
+    public OCAccount getOCAccount() {
-    public OCCredentials getCredentials() {
+        return mOCAccount;
-        return mCredentials;
-    }
-
-    public Uri getBaseUri() {
-        return mBaseUri;
     }
 }

src/com/owncloud/android/lib/refactor/RemoteOperation.java

@@ -1,5 +1,7 @@
 package com.owncloud.android.lib.refactor;
 
+import android.net.Uri;
+
 import java.util.Map;
 
 import okhttp3.OkHttpClient;
@@ -29,16 +31,26 @@ public abstract class RemoteOperation {
         return httpClient;
     }
 
+    public Uri.Builder getBaseUriBuilder() {
+        return mContext.getOCAccount().getBaseUri().buildUpon();
+    }
+
     public Request.Builder getRequestBuilder() {
         Request.Builder builder = new Request.Builder();
 
         for(Map.Entry<String, String> header
-                : mContext.getCredentials().getCredentialHeaders().entrySet()) {
+                : mContext.getOCAccount()
+                .getCredentials()
+                .getCredentialHeaders()
+                .entrySet()) {
             builder.addHeader(header.getKey(), header.getValue());
         }
 
         //TODO: Remove this part once SAML is obsolet
-        final String credentialCookie = mContext.getCredentials().getCredentialCookie();
+        final String credentialCookie = mContext
+                .getOCAccount()
+                .getCredentials()
+                .getCredentialCookie();
         if(credentialCookie == null) {
             builder.addHeader("Cookie", credentialCookie);
         }

src/com/owncloud/android/lib/refactor/RemoteOperationResult.java

@@ -27,7 +27,7 @@ package com.owncloud.android.lib.refactor;
 import android.accounts.Account;
 import android.accounts.AccountsException;
 
-import com.owncloud.android.lib.refactor.utils.AccountUtils;
+import com.owncloud.android.lib.refactor.exceptions.AccountNotFoundException;
 import com.owncloud.android.lib.refactor.exceptions.CertificateCombinedException;
 import com.owncloud.android.lib.refactor.exceptions.OperationCancelledException;
 import com.owncloud.android.lib.refactor.utils.ErrorMessageParser;
@@ -71,7 +71,7 @@ public class RemoteOperationResult implements Serializable {
     /**
      * Generated - should be refreshed every time the class changes!!
      */
-    private static final long serialVersionUID = 4968939884332372230L;
+    private static final long serialVersionUID = 4968939884332652230L;
 
     private static final String TAG = RemoteOperationResult.class.getSimpleName();
 
@@ -184,7 +184,7 @@ public class RemoteOperationResult implements Serializable {
         } else if (e instanceof UnknownHostException) {
             mCode = ResultCode.HOST_NOT_AVAILABLE;
 
-        } else if (e instanceof AccountUtils.AccountNotFoundException) {
+        } else if (e instanceof AccountNotFoundException) {
             mCode = ResultCode.ACCOUNT_NOT_FOUND;
 
         } else if (e instanceof AccountsException) {
@@ -444,9 +444,9 @@ public class RemoteOperationResult implements Serializable {
             if(mException instanceof DavException) return "Unexpected WebDAV exception";
             if(mException instanceof HttpException) return "HTTP violation";
             if(mException instanceof IOException) return "Unrecovered transport exception";
-            if(mException instanceof AccountUtils.AccountNotFoundException) {
+            if(mException instanceof AccountNotFoundException) {
                 Account failedAccount =
-                        ((AccountUtils.AccountNotFoundException) mException).getFailedAccount();
+                        ((AccountNotFoundException) mException).getFailedAccount();
                 return mException.getMessage() + " (" +
                         (failedAccount != null ? failedAccount.name : "NULL") + ")";
 

src/com/owncloud/android/lib/refactor/account/AccountTypeUtils.java

@@ -22,7 +22,7 @@
  *
  */
 
-package com.owncloud.android.lib.refactor.utils;
+package com.owncloud.android.lib.refactor.account;
 
 /**
  * @author masensio

src/com/owncloud/android/lib/refactor/account/AccountUtils.java

@@ -23,7 +23,7 @@
  *
  */
 
-package com.owncloud.android.lib.refactor.utils;
+package com.owncloud.android.lib.refactor.account;
 
 import android.accounts.Account;
 import android.accounts.AccountManager;
@@ -33,16 +33,23 @@ import android.accounts.OperationCanceledException;
 import android.content.Context;
 import android.net.Uri;
 
-import com.owncloud.android.lib.common.OwnCloudClient;
-import com.owncloud.android.lib.common.accounts.AccountTypeUtils;
-import com.owncloud.android.lib.common.authentication.OwnCloudCredentials;
 import com.owncloud.android.lib.common.authentication.OwnCloudCredentialsFactory;
-import com.owncloud.android.lib.common.utils.Log_OC;
+import com.owncloud.android.lib.refactor.Log_OC;
+import com.owncloud.android.lib.refactor.OCContext;
+import com.owncloud.android.lib.refactor.authentication.OCCredentials;
+import com.owncloud.android.lib.refactor.authentication.credentials.OCBasicCredentials;
+import com.owncloud.android.lib.refactor.authentication.credentials.OCBearerCredentials;
+import com.owncloud.android.lib.refactor.authentication.credentials.OCSamlSsoCredentials;
+import com.owncloud.android.lib.refactor.exceptions.AccountNotFoundException;
 import com.owncloud.android.lib.resources.status.OwnCloudVersion;
 
-import org.apache.commons.httpclient.Cookie;
+import org.apache.commons.httpclient.auth.AuthenticationException;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import okhttp3.Cookie;
 
 public class AccountUtils {
 
@@ -59,7 +66,7 @@ public class AccountUtils {
     public static String getWebDavUrlForAccount(Context context, Account account)
         throws AccountNotFoundException {
 
-        return getBaseUrlForAccount(context, account) + OwnCloudClient.WEBDAV_PATH_4_0;
+        return getBaseUrlForAccount(context, account) + OCContext.WEBDAV_PATH_4_0;
     }
 
 
@@ -121,73 +128,65 @@ public class AccountUtils {
     }
 
     /**
-     * @return
+     * @return OCCredentials
      * @throws IOException
      * @throws AuthenticatorException
      * @throws OperationCanceledException
      */
-    public static OwnCloudCredentials getCredentialsForAccount(Context context, Account account)
+
+    /**
+     *
+     * @param context an Android context
+     * @param account the coresponding Android account
+     * @return
+     * @throws OperationCanceledException
+     * @throws AuthenticatorException
+     * @throws IOException
+     */
+    public static OCCredentials getCredentialsForAccount(Context context, Account account)
         throws OperationCanceledException, AuthenticatorException, IOException {
 
-        OwnCloudCredentials credentials = null;
+        final AccountManager am = AccountManager.get(context);
-        AccountManager am = AccountManager.get(context);
+        final String supportsOAuth2 = am.getUserData(account, AccountUtils.Constants.KEY_SUPPORTS_OAUTH2);
-
+        final boolean isOauth2 = supportsOAuth2 != null && supportsOAuth2.equals("TRUE");
-        String supportsOAuth2 = am.getUserData(account, AccountUtils.Constants.KEY_SUPPORTS_OAUTH2);
-        boolean isOauth2 = supportsOAuth2 != null && supportsOAuth2.equals("TRUE");
-
         String supportsSamlSSo = am.getUserData(account,
                 AccountUtils.Constants.KEY_SUPPORTS_SAML_WEB_SSO);
-
+        final boolean isSamlSso = supportsSamlSSo != null && supportsSamlSSo.equals("TRUE");
-        boolean isSamlSso = supportsSamlSSo != null && supportsSamlSSo.equals("TRUE");
+        final String username = AccountUtils.getUsernameForAccount(account);
-
-        String username = AccountUtils.getUsernameForAccount(account);
-        OwnCloudVersion version = new OwnCloudVersion(am.getUserData(account, Constants.KEY_OC_VERSION));
 
         if (isOauth2) {
-            String accessToken = am.blockingGetAuthToken(
+            final String accessToken = am.blockingGetAuthToken(
                 account,
                 AccountTypeUtils.getAuthTokenTypeAccessToken(account.type),
                 false);
 
-            credentials = OwnCloudCredentialsFactory.newBearerCredentials(username, accessToken);
+            return new OCBearerCredentials(username, accessToken);
 
         } else if (isSamlSso) {
-            String accessToken = am.blockingGetAuthToken(
-                account,
-                AccountTypeUtils.getAuthTokenTypeSamlSessionCookie(account.type),
-                false);
 
-            credentials = OwnCloudCredentialsFactory.newSamlSsoCredentials(username, accessToken);
+            try {
+                final String accessToken = am.blockingGetAuthToken(
+                        account,
+                        AccountTypeUtils.getAuthTokenTypeSamlSessionCookie(account.type),
+                        false);
+
+                return new OCSamlSsoCredentials(username, accessToken,
+                        Uri.parse(getBaseUrlForAccount(context, account)));
+            } catch (AccountNotFoundException e) {
+                throw new AuthenticationException("Account not found", e);
+            }
 
         } else {
-            String password = am.blockingGetAuthToken(
+            final String password = am.blockingGetAuthToken(
                 account,
                 AccountTypeUtils.getAuthTokenTypePass(account.type),
                 false);
 
-            credentials = OwnCloudCredentialsFactory.newBasicCredentials(
+            return new OCBasicCredentials(username, password);
-                username,
-                password,
-                version.isPreemptiveAuthenticationPreferred()
-            );
         }
-
-        return credentials;
-
     }
 
 
-    public static String buildAccountNameOld(Uri serverBaseUrl, String username) {
-        if (serverBaseUrl.getScheme() == null) {
-            serverBaseUrl = Uri.parse("https://" + serverBaseUrl.toString());
-        }
-        String accountName = username + "@" + serverBaseUrl.getHost();
-        if (serverBaseUrl.getPort() >= 0) {
-            accountName += ":" + serverBaseUrl.getPort();
-        }
-        return accountName;
-    }
-
     public static String buildAccountName(Uri serverBaseUrl, String username) {
         if (serverBaseUrl.getScheme() == null) {
             serverBaseUrl = Uri.parse("https://" + serverBaseUrl.toString());
@@ -203,80 +202,60 @@ public class AccountUtils {
         return accountName;
     }
 
-    public static void saveClient(OwnCloudClient client, Account savedAccount, Context context) {
+    public static void saveCookies(List<Cookie> cookies, Account savedAccount, Context context) {
 
         // Account Manager
         AccountManager ac = AccountManager.get(context.getApplicationContext());
 
-        if (client != null) {
+        if (cookies != null && cookies.size() != 0) {
-            String cookiesString = client.getCookiesString();
+            StringBuilder cookiesString = new StringBuilder();
-            if (!"".equals(cookiesString)) {
+            for (Cookie cookie : cookies) {
-                ac.setUserData(savedAccount, Constants.KEY_COOKIES, cookiesString);
+                cookiesString.append(cookiesString + cookie.toString() + ";");
-                // Log_OC.d(TAG, "Saving Cookies: "+ cookiesString );
             }
+
+            ac.setUserData(savedAccount, Constants.KEY_COOKIES, cookiesString.toString());
         }
 
     }
 
 
     /**
-     * Restore the client cookies persisted in an account stored in the system AccountManager.
+     *  Restore the client cookies persisted in an account stored in the system AccountManager.
      *
-     * @param account           Stored account.
+     * @param account
-     * @param client            Client to restore cookies in.
+     * @param context
-     * @param context           Android context used to access the system AccountManager.
+     * @return
+     * @throws AccountsException
      */
-    public static void restoreCookies(Account account, OwnCloudClient client, Context context) {
+    public static List<Cookie> getCookiesFromAccount(Account account, Context context) throws AccountsException {
         if (account == null) {
             Log_OC.d(TAG, "Cannot restore cookie for null account");
+            return new ArrayList<>();
+        }
 
-        } else {
+        Log_OC.d(TAG, "Restoring cookies for " + account.name);
-            Log_OC.d(TAG, "Restoring cookies for " + account.name);
 
-            // Account Manager
+        final AccountManager am = AccountManager.get(context.getApplicationContext());
-            AccountManager am = AccountManager.get(context.getApplicationContext());
+        final Uri serverUri = Uri.parse(getBaseUrlForAccount(context, account));
+        final String cookiesString = am.getUserData(account, Constants.KEY_COOKIES);
+        final List<Cookie> cookies = new ArrayList<>();
 
-            Uri serverUri = (client.getBaseUri() != null) ? client.getBaseUri() : client.getWebdavUri();
+        if (cookiesString != null) {
+            String[] rawCookies = cookiesString.split(";");
+            for (String rawCookie : rawCookies) {
+                final int equalPos = rawCookie.indexOf('=');
 
-            String cookiesString = am.getUserData(account, Constants.KEY_COOKIES);
+                cookies.add(new Cookie.Builder()
-            if (cookiesString != null) {
+                        .name(rawCookie.substring(0, equalPos))
-                String[] cookies = cookiesString.split(";");
+                        .value(rawCookie.substring(equalPos + 1))
-                if (cookies.length > 0) {
+                        .domain(serverUri.getHost())
-                    for (int i = 0; i < cookies.length; i++) {
+                        .path(serverUri.getPath())
-                        Cookie cookie = new Cookie();
+                        .build());
-                        int equalPos = cookies[i].indexOf('=');
-                        cookie.setName(cookies[i].substring(0, equalPos));
-                        cookie.setValue(cookies[i].substring(equalPos + 1));
-                        cookie.setDomain(serverUri.getHost());    // VERY IMPORTANT
-                        cookie.setPath(serverUri.getPath());    // VERY IMPORTANT
-
-                        client.getState().addCookie(cookie);
-                    }
-                }
             }
         }
+        return cookies;
     }
 
-    public static class AccountNotFoundException extends AccountsException {
-
-        /**
-         * Generated - should be refreshed every time the class changes!!
-         */
-        private static final long serialVersionUID = -1684392454798508693L;
-
-        private Account mFailedAccount;
-
-        public AccountNotFoundException(Account failedAccount, String message, Throwable cause) {
-            super(message, cause);
-            mFailedAccount = failedAccount;
-        }
-
-        public Account getFailedAccount() {
-            return mFailedAccount;
-        }
-    }
-
-
     public static class Constants {
         /**
          * Version should be 3 numbers separated by dot so it can be parsed by

src/com/owncloud/android/lib/refactor/account/OCAccount.java

@@ -0,0 +1,155 @@
+/* ownCloud Android Library is available under MIT license
+ *   Copyright (C) 2016 ownCloud GmbH.
+ *
+ *   Permission is hereby granted, free of charge, to any person obtaining a copy
+ *   of this software and associated documentation files (the "Software"), to deal
+ *   in the Software without restriction, including without limitation the rights
+ *   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ *   copies of the Software, and to permit persons to whom the Software is
+ *   furnished to do so, subject to the following conditions:
+ *
+ *   The above copyright notice and this permission notice shall be included in
+ *   all copies or substantial portions of the Software.
+ *
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ *   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ *   BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ *   ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ *   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ *   THE SOFTWARE.
+ *
+ */
+
+package com.owncloud.android.lib.refactor.account;
+
+
+import android.accounts.Account;
+import android.accounts.AccountManager;
+import android.accounts.AuthenticatorException;
+import android.accounts.OperationCanceledException;
+import android.content.Context;
+import android.net.Uri;
+
+import com.owncloud.android.lib.refactor.authentication.OCCredentials;
+import com.owncloud.android.lib.refactor.authentication.credentials.OCAnonymousCredentials;
+import com.owncloud.android.lib.refactor.exceptions.AccountNotFoundException;
+
+import java.io.IOException;
+
+/**
+ * OwnCloud Account
+ * 
+ * @author David A. Velasco
+ */
+public class OCAccount {
+
+    private Uri mBaseUri;
+    private OCCredentials mCredentials;
+    private String mDisplayName;
+    private String mSavedAccountName;
+    private Account mSavedAccount;
+
+
+    /**
+     * Constructor for already saved OC accounts.
+     *
+     * Do not use for anonymous credentials.
+     */
+    public OCAccount(Account savedAccount, Context context) throws AccountNotFoundException {
+        if (savedAccount == null) {
+            throw new IllegalArgumentException("Parameter 'savedAccount' cannot be null");
+        }
+
+        if (context == null) {
+            throw new IllegalArgumentException("Parameter 'context' cannot be null");
+        }
+
+        mSavedAccount = savedAccount;
+        mSavedAccountName = savedAccount.name;
+        mCredentials = null;    // load of credentials is delayed
+
+        AccountManager ama = AccountManager.get(context.getApplicationContext());
+        String baseUrl = ama.getUserData(mSavedAccount, AccountUtils.Constants.KEY_OC_BASE_URL);
+        if (baseUrl == null ) {
+            throw new AccountNotFoundException(mSavedAccount, "Account not found", null);
+        }
+        mBaseUri = Uri.parse(AccountUtils.getBaseUrlForAccount(context, mSavedAccount));
+        mDisplayName = ama.getUserData(mSavedAccount, AccountUtils.Constants.KEY_DISPLAY_NAME);
+    }
+
+
+    /**
+     * Constructor for non yet saved OC accounts.
+     *
+     * @param baseUri           URI to the OC server to get access to.
+     * @param credentials       Credentials to authenticate in the server. NULL is valid for anonymous credentials.
+     */
+    public OCAccount(Uri baseUri, OCCredentials credentials) {
+        if (baseUri == null) {
+            throw new IllegalArgumentException("Parameter 'baseUri' cannot be null");
+        }
+        mSavedAccount = null;
+        mSavedAccountName = null;
+        mBaseUri = baseUri;
+        mCredentials = credentials != null
+                ? credentials
+                : new OCAnonymousCredentials();
+        String username = mCredentials.getUsername();
+        if (username != null) {
+            mSavedAccountName = AccountUtils.buildAccountName(mBaseUri, username);
+        }
+    }
+
+    /**
+     * Method for deferred load of account attributes from AccountManager
+     *
+     * @param context
+     * @throws AccountNotFoundException
+     * @throws AuthenticatorException
+     * @throws IOException
+     * @throws OperationCanceledException
+     */
+    public void loadCredentials(Context context)
+        throws AccountNotFoundException, AuthenticatorException,
+                IOException, OperationCanceledException {
+
+        if (context == null) {
+            throw new IllegalArgumentException("Parameter 'context' cannot be null");
+        }
+
+        if (mSavedAccount != null) {
+            mCredentials = AccountUtils.getCredentialsForAccount(context, mSavedAccount);
+        }
+    }
+
+    public Uri getBaseUri() {
+        return mBaseUri;
+    }
+            
+    public OCCredentials getCredentials() {
+        return mCredentials;
+    }
+    
+    public String getName() {
+    	return mSavedAccountName;
+    }
+
+    public Account getSavedAccount() {
+        return mSavedAccount;
+    }
+
+    public String getDisplayName() {
+        if (mDisplayName != null && mDisplayName.length() > 0) {
+            return mDisplayName;
+        } else if (mCredentials != null) {
+            return mCredentials.getUsername();
+        } else if (mSavedAccount != null) {
+            return AccountUtils.getUsernameForAccount(mSavedAccount);
+        } else {
+            return null;
+        }
+    }
+
+}

src/com/owncloud/android/lib/refactor/authentication/oauth/operations/OAuth2GetAccessTokenOperation.java

@@ -84,13 +84,6 @@ public class OAuth2GetAccessTokenOperation extends RemoteOperation {
     @Override
     public RemoteOperationResult exec() {
         try {
-
-            final Uri uri = getOCContext()
-                    .getBaseUri()
-                    .buildUpon()
-                    .appendEncodedPath(mAccessTokenEndpointPath)
-                    .build();
-
             final RequestBody requestBody = new MultipartBody.Builder()
                     .setType(MultipartBody.FORM)
                     .addFormDataPart(OAuth2Constants.KEY_GRANT_TYPE, mGrantType)
@@ -100,7 +93,10 @@ public class OAuth2GetAccessTokenOperation extends RemoteOperation {
                     .build();
 
             final Request request = getRequestBuilder()
-                    .url(uri.toString())
+                    .url(getBaseUriBuilder()
+                            .appendEncodedPath(mAccessTokenEndpointPath)
+                            .build()
+                            .toString())
                     .method("POST", requestBody)
                     .build();
 
@@ -109,6 +105,7 @@ public class OAuth2GetAccessTokenOperation extends RemoteOperation {
                     .execute();
 
             final String responseData = response.body().string();
+            
             if (responseData != null && responseData.length() > 0) {
                 JSONObject tokenJson = new JSONObject(responseData);
                 Map<String, String> accessTokenResult =

src/com/owncloud/android/lib/refactor/authentication/oauth/operations/OAuth2RefreshAccessTokenOperation.java

@@ -79,8 +79,6 @@ public class OAuth2RefreshAccessTokenOperation extends RemoteOperation {
     @Override
     public RemoteOperationResult exec() {
         try {
-
-
             final RequestBody requestBody = new MultipartBody.Builder()
                     .setType(MultipartBody.FORM)
                     .addFormDataPart(OAuth2Constants.KEY_GRANT_TYPE,
@@ -90,20 +88,15 @@ public class OAuth2RefreshAccessTokenOperation extends RemoteOperation {
                     .build();
 
             final Request request = getRequestBuilder()
-                    .url(getOCContext().getBaseUri().buildUpon()
+                    .url(getBaseUriBuilder()
                             .appendEncodedPath(mAccessTokenEndpointPath)
                             .build()
                             .toString())
                     .method("POST", requestBody)
                     .build();
 
-
-            OCCredentials oauthCredentials = new OCBasicCredentials(
-                    mClientId,
-                    mClientSecret
-            );
-
             final Response response = getClient().newCall(request).execute();
+
             final String responseData = response.body().string();
             Log_OC.d(TAG, "OAUTH2: raw response from POST TOKEN: " + responseData);
 

src/com/owncloud/android/lib/refactor/exceptions/AccountNotFoundException.java

@@ -0,0 +1,23 @@
+package com.owncloud.android.lib.refactor.exceptions;
+
+import android.accounts.Account;
+import android.accounts.AccountsException;
+
+public class AccountNotFoundException extends AccountsException {
+
+    /**
+     * Generated - should be refreshed every time the class changes!!
+     */
+    private static final long serialVersionUID = -1684392454778508693L;
+
+    private Account mFailedAccount;
+
+    public AccountNotFoundException(Account failedAccount, String message, Throwable cause) {
+        super(message, cause);
+        mFailedAccount = failedAccount;
+    }
+
+    public Account getFailedAccount() {
+        return mFailedAccount;
+    }
+}

src/com/owncloud/android/lib/refactor/operations/PropfindOperation.java

@@ -13,6 +13,7 @@ public class PropfindOperation extends RemoteOperation {
     @Override
     public RemoteOperationResult exec() {
 
+
         return null;
     }
 }