联系人ProfileProvider (四)

/**
* Performs a permission check on the write profile permission.
*/
public void enforceWritePermission() {//检查是否有写权限
mDelegate.getContext().enforceCallingOrSelfPermission(WRITE_PERMISSION, null);
}
/**
* 重写getDatabaseHelper，父类的方法
*/
@Override
protected ProfileDatabaseHelper getDatabaseHelper(Context context) {
return ProfileDatabaseHelper.getInstance(context);
}

@Override
protected ThreadLocal getTransactionHolder() {//得到线程本地存储的对象
return mDelegate.getTransactionHolder();
}

@Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
String sortOrder) {
enforceReadPermission(uri);//检查权限，如果没有权限抛出异常
mDelegate.substituteDb(getDatabaseHelper().getReadableDatabase());//替换数据库 profile.db
return mDelegate.queryLocal(uri, projection, selection, selectionArgs, sortOrder, -1);
}

@Override
protected Uri insertInTransaction(Uri uri, ContentValues values) {
enforceWritePermission();//检查写权限，如果不存在权限，抛出异常
useProfileDbForTransaction();//启动触发器，并切换数据库到profile.db
return mDelegate.insertInTransaction(uri, values);
}

@Override
protected int updateInTransaction(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {
enforceWritePermission();//检查写权限，如果不存在权限，抛出异常
useProfileDbForTransaction();//启动触发器，并切换数据库到profile.db
return mDelegate.updateInTransaction(uri, values, selection, selectionArgs);
}

@Override
protected int deleteInTransaction(Uri uri, String selection, String[] selectionArgs) {
enforceWritePermission();//检查写权限，如果不存在权限，抛出异常
useProfileDbForTransaction();//启动触发器，并切换数据库到profile.db
return mDelegate.deleteInTransaction(uri, selection, selectionArgs);
}

@Override
public AssetFileDescriptor openAssetFile(Uri uri, String mode) throws FileNotFoundException {
if (mode != null && mode.contains("w")) {
enforceWritePermission();//检查写权限，如果不存在权限，抛出异常
mDelegate.substituteDb(getDatabaseHelper().getWritableDatabase());//切换到profile.db上
} else {
enforceReadPermission(uri);//检查权限，如果不存在权限，抛出异常
mDelegate.substituteDb(getDatabaseHelper().getReadableDatabase());
}
return mDelegate.openAssetFileLocal(uri, mode);
}

private void useProfileDbForTransaction() {
ContactsTransaction transaction = getCurrentTransaction();//得到线程本地存储，mTreasactionLocal来自mDelegate对象
SQLiteDatabase db = getDatabaseHelper().getWritableDatabase();//子类重写了getDatabaseHelper（）方法 profile.db。
transaction.startTransactionForDb(db, ContactsProvider2.PROFILE_DB_TAG, this);
mDelegate.substituteDb(db);//切换数据库到profile.db
}

@Override
protected void notifyChange() {
mDelegate.notifyChange();
}

protected void notifyChange(boolean syncToNetwork) {
mDelegate.notifyChange(syncToNetwork);
}

protected Locale getLocale() {
return mDelegate.getLoca