Hello I'm coding a simple CRUDE application that runs perfectly using JSF and DB4O.
I can add and list all the entities normally without errors.
I've used this code to persist the entities
bd = Db4oEmbedded.openFile(configuration, "db.data");
bd.store(client);
bd.commit();
the problem is that I cant locate the db.data file. I,ve done a search in the whole PC and still cant find it.
soo where DB4O store those entities, how is it possible??
thank you.
It must be in your project execution path. Usually db4o file name is called with extension yap. Better you can use relative path to the database file like
String dbPath = "c:/db/project.yap"; // better read from project resource
EmbeddedObjectContainer openFile = Db4oEmbedded.openFile(dbPath);
Related
My question seems to be pretty straight forward but, I haven't been able to find any solutions to this online. I've looked at a number of different types of objects like DataTables and DataAssets only to realize they are for static data alone.
The goal of my project is to have data-driven configurable assets where we can choose different configurations for our different objects. I have been able to successfully pull JSON data down from the database at run-time but, I would like to save said data to something like a Data Asset or something similar that I can read and write to. So when we pull from said database later we only pull updates to our different configurations and not the entire database (every time at start-up).
On a side note: would this be possible/feasible using an .ini file or is this kind of thing considered too big for something like that (i.e 1000+ json objects)?
Any solutions to this problem would be greatly appreciated.
Like you say, DataTable isn't really usable here. You'll need to utilize UE4's various File IO API utilities.
Obtaining a Local Path
This function converts a path relative to your intended save directory, into one that's relative to the UE4 executable, which is the format expected throughout UE4's File IO.
//DataUtilities.cpp
FString DataUtilities::FullSavePath(const FString& SavePath) {
return FPaths::Combine(FPaths::ProjectSavedDir(), SavePath);
}
"Campaign/profile1.json" as input would result in something like:
"<game.exe>/game/Saved/Campaign/profile1.json".
Before you write anything locally, you should find the appropriate place to do it. Using ProjectSaveDir() results in saving files to <your_game.exe>/your_game/Saved/ in packaged builds, or in your project's Saved folder in development builds. Additionally, FPaths has other named Dir functions if ProjectSavedDir() doesn't suit your purpose.
Using FPaths::Combine to concatenate paths is less error-prone than trying to append strings with '/'.
Storing generated JSON Text Data on Disk
I'll assume you have a valid JSON-filled FString (as opposed to a FJSONObject), since generating valid JSON is fairly trivial.
You could just try to write directly to the location of the full path given by the above function, but if the directory tree to it doesn't exist (i.e., first-run), it'll fail. So, to generate that path tree, there's some path processing and PlatformFile usage.
//DataUtilities.cpp
void DataUtilities::WriteSaveFile(const FString& SavePath, const FString& Data) {
auto FullPath = FullSavePath(SavePath);
FString PathPart, Disregard;
FPaths::Split(FullPath, PathPart, Disregard, Disregard);
IPlatformFile& PlatformFile = FPlatformFileManager::Get().GetPlatformFile();
if (PlaftormFile.CreateDirectoryTree(*PathPart)){
FFileHelper::SaveStringToFile(Data, *FullPath);
}
}
If you're unsure what any of this does, read up on FPaths and FPlatformFileManager in the documentation section below.
As for generating a JSON string: Instead of using the Json module's DOM, I generate JSON strings directly from my FStructs when needed, so I don't have experience with using the Json module's serialization functionality. This answer seems to cover that pretty well, however, if you go that route.
Pulling Textual Data off the Disk
// DataUtilities.cpp
bool DataUtilities::SaveFileExists(const FString& SavePath) {
return IFileManager::Get().FileExists(*FullSavePath(SavePath));
}
FString DataUtilities::ReadSaveFile(const FString& SavePath) {
FString Contents;
if(SaveFileExists(SavePath)) {
FFileHelper::LoadFileToString(Contents, *FullSavePath(SavePath));
}
return Contents;
}
As is fairly obvious, this only works for string or string-like data, of which JSON qualifies.
You could consolidate SaveFileExists into ReadSaveFile, but I found benefit in having a simple "does-this-exist" probe for other methods. YMMV.
I assume if you're already pulling JSON off a server, you have a means of deserializing it into some form of traversable container. If you don't, this is an example from the UE4 Answer Hub of using the Json module to do so.
Relevant Documentation
FFileHelper
FFileHelper::LoadFileToString
FFileHelper::SaveStringToFile
IFileManager
FPlatformFileManager
FPaths
UE4 Json.h (which you may already be using)
To address your side note: I would suggest using an extension that matches the type of content saved, if for nothing other than clarity of intention. I.e., descriptive_name.json for files containing JSON. If you know ahead of time that you will be reading/needing all hundreds or thousands of JSON objects at once, it would likely be better to group as many as possible into fewer files, to minimize overhead.
I am using the Drupal 7 Migrate module to create a series of nodes from JPG and EPS files. I can get them to import just fine. But I notice that when I am done importing them if I look at the nodes it creates, none of the attached filefield and thumbnail files contain filename information.
Upon inspecting the file_managed table I see that both the filename and filemime fields are empty for ONLY the files that I attached via the migrate module. This also creates an issue with downloading the files.
Now I think the problem has to do with the fact that I am using "file_link" instead of "file_copy" as the file operation I specify. The problem is I am importing around 2TB (thats Terabytes) of image files. We had to put in a special request with Rackspace just to get access to that much disk space on our server. So I can't go around copying from one directory to the next because of space issues. So "file_link" seems like the obvious choice.
Now you probably want to see how I am doing this exactly, so here is the code snippet:
$jpg_arguments = MigrateFileFieldHandler::arguments(NULL,
'file_link', FILE_EXISTS_RENAME, 'en', array('source_field' => 'jpg_name'),
array('source_field' => 'jpg_filename'), array('source_field' => 'jpg_filename'));
$this->addFieldMapping('field_image', 'jpg_uri')
->arguments($jpg_arguments);
As you can see I am specifying no base path (just like the beer.inc example file does). I have set file_link, the language, and the source fields for the description, title, and alt.
It is able to generate thumbnails from the JPGs. But still missing those columns of data in the db table. I traced through the functions the best I could but I don't see what is causing this. I tried running the uri in the table through the functions that generate the filename and the filemime and they output just fine. It is like something is removing just those segments of data.
Does anyone have any idea what this could be? I am using the Drupal 7 Migrate module version 2.2. It is running on Drupal 7.8.
Thanks,
Patrick
Ok, so I have found the answer to yet another question of mine. This is actually an issue with the migrate module itself. The issue is documented here. I will be repealing this bounty (as soon as I figure out how).
I'm including a number of images as "Content" in my deployed XAP for Mango.
I'd like to enumerate these at runtime - is there any way to do this?
I've tried enumerating resources like:
foreach (string key in Application.Current.Resources.Keys)
{
Debug.WriteLine("Resource:" + key);
}
But the images aren't included in the list. I've also tried using embedded resources instead - but that didn't help. I can read the streams using Application.GetResourceStream(uri) but obviously I need to know the names in order to do this.
This is no API baked in to WP7 that allows you to enumerate the contents of the Xap. You need to know the name of the content items before you can retreive them.
There probably is some code floating around somewhere that is able to sniff out the Zip catalog in the XAP however I would strongly recommend that you don't bother. Instead include some sensible resource such as an Xml file or ResourceDictionary that lists them.
Having found no practical way to read the Content files from a XAP I build such a list at design time using T4.
See an example at https://github.com/mrlacey/phonegap-wp7/blob/master/WP7Gap/WP7Gap/MainPage.xaml.cs
This seems the right way to go as:
a) I'd rather build the list once at design time rather than on every phone which needs the code.
and
b) I shouldn't ever be building the XAP without being certain about what files I'm including anyway.
Plus it's a manual step to set the build action on all such files so adding a manual step to "Run Custom Tool" once for each build isn't an issue for me.
There is no way to enumerate the files set as "Content".
However, there is a way to enumerate files at runtime, if you set your files as "Embedded Resource".
Here is how you can do this:
Set the Build Action of your images as "Embedded Resource".
Use Assembly.GetCallingAssembly().GetManifestResourceNames() to
enumerate the resources names
Use
Assembly.GetCallingAssembly().GetManifestResourceStream(resName)
to get the file streams.
Here is the code:
public void Test()
{
foreach (String resName in GetResourcesNames())
{
Stream s = GetStreamFromEmbeddedResource(resName);
}
}
string[] GetResourcesNames()
{
return Assembly.GetCallingAssembly().GetManifestResourceNames();
}
Stream GetStreamFromEmbeddedResource(string resName)
{
return Assembly.GetCallingAssembly().GetManifestResourceStream(resName);
}
EDIT : As quetzalcoatl noted, the drawback of this solution is that images are embedded in the DLL, so if you a high volume of images, the app load time might take a hit.
I currently am loading all images in a folder in my "MyPictures" folder on my machine which works fine...
foreach (string filename in Directory.GetFiles(Environment.GetFolderPath(Environment.SpecialFolder.MyPictures)))
What I really want to be able to do, though, is load all the images in my Images folder within my solution project. Can someone please tell me the correct syntax to do this?
[Nothing in your question (as it is currently stated) is really directly related to WPF as opposed to C# (and Windows development) in general, as far as I can tell. You might get a better reply if the question was tagged to C# as opposed to just WPF.]
I don't think there is a way to reference your solution's folder as such (nor does it really make much sense, as the users of your application won't in general have the solution, only the distributables).
If you need the directory to be within your solution folder somehow, maybe you should refer to the directory your executable resides in (...\SolutionDir\bin\Debug), which you can get using
System.IO.Path.GetDirectoryName(
System.Reflection.Assembly.GetExecutingAssembly()
.GetModules()[0].FullyQualifiedName);
(Of course, you could tack \..\.. to that to refer to the SolutionDir instead, but that'd be a bit ugly.)
Depending on the usage of the images, though, it'd probably be better to put them under one of the defined special directories -- Environment.SpecialFolder.CommonApplicationData sounds like the best candidate, if the images are to be shared by all users.
One way to access images stored in a folder inside the WPF project is to do the following:
If you have already added the images inside an Images folder, Add the images file names in the Resources.resx file under Properties. You can access the images in the code by the following
string imageFilename = "pack://application:,,,/APP.UI;component/Images/" + Properties.Resources.imagefilename;
var src = new BitmapImage();
src.UriSource = new Uri(imageFilename , UriKind.Absolute);
A friend of mine is now building a web application with J2EE and Struts, and it's going to be prepared to display pages in several languages.
I was told that the best way to support a multi-language site is to use a properties file where you store all the strings of your pages, something like:
welcome.english = "Welcome!"
welcome.spanish = "¡Bienvenido!"
...
This solution is ok, but what happens if your site displays news or something like that (a blog)? I mean, content that is not static, that is updated often... The people that keep the site have to write every new entry in each supported language, and store each version of the entry in the database. The application loads only the entries in the user's chosen language.
How do you design the database to support this kind of implementation?
Thanks.
Warning: I'm not a java hacker, so YMMV but...
The problem with using a list of "properties" is that you need a lot of discipline. Every time you add a string that should be output to the user you will need to open your properties file, look to see if that string (or something roughly equivalent to it) is already in the file, and then go and add the new property if it isn't. On top of this, you'd have to hope the properties file was fairly human readable / editable if you wanted to give it to an external translation team to deal with.
The database based approach is useful for all your database based content. Ideally you want to make it easy to tie pieces of content together with their translations. It only really falls down for all the places you may want to output something that isn't out of a database (error messages etc.).
One fairly old technology which we find still works really well, is to use gettext. Gettext or some variant seems to be available for most languages and platforms. The basic premise is that you wrap your output in a special function call like so:
echo _("Please do not press this button again");
Then running the gettext tools over your source code will extract all the instances wrapped like that into a "po" file. This will contain entries such as:
#: myfolder/my.source:239
msgid "Please do not press this button again"
msgstr ""
And you can add your translation to the appropriate place:
#: myfolder/my.source:239
msgid "Please do not press this button again"
msgstr "s’il vous plaît ne pas appuyer sur le bouton ci-dessous à nouveau"
Subsequent runs of the gettext tools simply update your po files. You don't even need to extract the po file from your source. If you know you may want to translate your site down the line, then you can just use the format shown above (the underscored function) with all your output. If you don't provide a po file it will just return whatever you put in the quotes. gettext is designed to work with locales so the users locale is used to retrieve the appropriate po file. This makes it really easy to add new translations.
Gettext Pros
Doesn't get in your way while coding
Very easy to add translations
PO files can be compiled down for speed
There are libraries available for most languages / platforms
There are good cross platform tools for dealing with translations. It is actually possible to get your translation team set up with a tool such as poEdit to make it very easy for them to manage translation projects
Gettext Cons
Solves your site "furniture" needs, but you would usually still want a database based approach for your database driven content
For more info on gettext see this wikipedia page
They way I have designed the database before is to have an News-table containing basic info like NewsID (int), NewsPubDate (datetime), NewsAuthor (varchar/int) and then have a linked table NewsText that has these columns: NewsID(int), NewsText(text), NewsLanguageID(int). And at last you have a Language-table that has LanguageID(int) and LanguageName(varchar).
Then, when you want to show your users the news-page you do:
SELECT NewsText FROM News INNER JOIN NewsText ON News.NewsID = NewsText.NewsID
WHERE NewsText.NewsLanguageID = <<Session["UserLanguageID"]>>
That Session-bit is a local variable where you store the users language when they log in or enters the site for the first time.
Java web applications support internationalization using the java standard tag library.
You've really got 2 problems. Static content and dynamic content.
for static content you can use jstl. It uses java ResourceBundles to accomplish this. I managed to get a Databased backed bundle working with the help of this site.
The second problem is dynamic content.
To solve this problem you'll need to store the data so that you can retrieve different translations based on the user's Locale. (Locale includes Country and Language).
It's not trivial, but it is something you can do with a little planning up front.
#Auron
thats what we apply it to. Our apps are all PHP, but gettext has a long heritage.
Looks like there is a good Java implementation
Tag libraries are fine if you're using JSP, but you can also achieve I18N using a template-based technology such as FreeMarker.