I am using Java language
What I want is that Can any one help me to write a code that
When i click on delete option of any file or folder I get notify before delete that I ma deleting a file Whether I want to continue ?
I have seen many examples that notify after the file is deleted.
One thing I want to make clear is as I click on file placed Desktop or My document directory I must get notify that
You are deleting a file .do you want to continue ?
What I really need is I want the exact answer or code
Please help
I shall be very thankful to you
No, this is not possible in Java. The operating system handles the file access, and another process is not capable of preventing the system denying access to those files. The only way you could do this is by having a file system written in Java (say, a loopback mounted WebDAV share) to which you could intercept the file requests with this kind of information. But not only would this be difficult to achieve, it also would only work if all of the access you are doing is via your loopback mounted system; it wouldn't work for files located on the disk or from other network shares.
So, in summary, you cannot do this with any programming language without writing your own filesystem and using that to intercept requests.
Related
I saw the project Hive2Hive, I think it is a very good project and I am very interest.
I am involved with a project, that has to save the files of different applications in a File System just like this one.
See image here
Let me describe the structure of this project:
There are 2 Applications in 2 different servers.
The Agent:
is responsible to send the content of a folder to a Collector
This content is a snippet of the file
only sends information if the Collector asks
it listens the Collector and sends the content by the same door
after sending it, might delete or truncate the file or o nothing else
it needs the key(.ssh/id_rsa) and if necessary a user
With the key, it can do an context switch or user switch, thus being able to delete or truncate the file
it communicates with only a Collector
it needs the folder, where to search, an included list, excluded list and an action list
These lists are patterns
The action list, decides if the file will be deleted or truncated.
The Collector:
saves the content in a File System
knows, which content was saved in the File System
it can connect to many Agents
This application was developed by "our selfs" , but is very unreliable.
Files are deleted without knowing
Allot of spaghetti code and very old
Very little time to repair it and very hard to repair
When I saw the hive2hive, I see many interesting features:
File Synchronization
File Versioning and Conflict Management
File Watchdog / Change Detection (automated, configurable)
Users can use multiple clients (simulatenously)
Multiple users can use the same machine (simultaneously)
I would like to run the application headless, a program that runs in the background.
I have some questions:
How can I decide which files to synch?
I could have a list of files selected by a pattern, for example *.log
How can I send from a source server to a destination server and keep Versioning?
Is it possible to use key files?
Most of the examples were with user credentials. I prefer key file
How should I configure it?
4.1. Should I have 2 application?
One in the source the other in the destination
4.2. Should I have only one application?
Where should it be? Source or Destination
Can I keep the same format, many Agents and few Collectors?
I am the only person, that can implement this application, because of the time I am asking for help.
I would like to hear your opinion and advice.
Thank you very much in advance,
Best regards,
Luís
I'm opening many types of files using external applications which are available on phone. For security reasons I need to delete this file when the external app does not need it. How can I check if I can safely remove file which are used by third app ?
First of all you need to know which files are used by the third app. You can simply do it by analyzing, (decompiling, if needed) the source code of the application. After knowing all the files used by the third party app you need to check if the third party app actually running or not, because the third party app might use some temporary files, which could be removed when it's no longer open.
If you just want to make a simple cleaner, which cleans the trash of all the apps, then you should simply just remove certain file types (like .tmp files) and remove the cache of the apps.
First of all, I think there is no 100% way to determine if file is not used by another application.
I you are asking about files in sandbox of other apps, by the way you be able to remove such files because they have granted permissions only for app that they are belong to. So you need root access in this case.
You can remove file like cache,tmp ... files like system app manager does. If third-party is built correctly this should not affect application.
Also another method is to determine how often file is being used is based on unix file timestamps, they are
Access - the last time the file was read
Modify - the last time the file was modified (content has been modified)
Change - the last time meta data of the file was changed (e.g. permissions)
You can check for example the date when app was installed, than check access time of the file and determine does the application require this file.
But again there is no 100% guarantee that you won't brake an app.
When we want to load a static file e.g. a picture, a sound file, a file containing information about a game map,... we can store them as resources in jar file and use getClass.getResource("images/splash.png") (also getResourceAsStream) to load and use them. But when we want to read and write into a file like settings file, I don't think using resources is a good way, because i think resources are designed to store read/only files that are not supposed to change, like splash screen image or a game's background music; These are my reasons to think this way:
That is why return value of getResourceAsStream is an instance of InputStream and we don't have a similar function which gives us an OutputStream, because we're not supposed to alter resource files.
Writing into resources changes program .jar file and i guess it's not a good thing at all; Because if we do so: we can't use check-sums to verify file, if we are a limited user and system administrator doesn't give us write permission we can't make changes into main .jar file, user-specific preferences are hard or impossible to implement,...
So, my questions are:
Which parts of my thoughts and assumptions are right or wrong?
If they're right what is the best(I mean short and portable between OSs and Computers) way to store files like that? (Application setting/preferences, A game save file, ...)
(#Some user who may wants to mark this as duplicate: I don't think my question is a duplicate, i searched in the site, I admit it has some common parts with some questions but it's not duplicate!)
Your three observations in #2 above are valid reasons not to store settings in a resource file, regardless of the APIs provided.
There are a variety of ways to save settings in Java, including:
The Java system property "user.home" provides the user's home directory, to which the user should have write access. You can create an application-specific subdirectory underneath it.
Java provides a Preferences API. This may store settings in a directory or (on Windows) in the registry.
OSGI provides a preferences API.
If you're using the Eclipse RCP, you can write to the configuration directory using a ConfigurationScope. See the Eclipse FAQ "What is a preference scope").
I have a web application in GWT and a complementary desktop client also written in Java (so the same solution basically applies to both). In my program users can attach files, then download them later or do whatever. These files are stored as blobs and can be in just about any format. Many of the users that use Excel and Word want to be able to open the file, make changes, then have those changes stored back in the attached file. In other words, need an inline editing of attachments.
Any ideas on how to make this happen? Should I have an 'edit' mode that keeps a file handler while the file is open, and then store that File handler? Some way keeping track of whether the file is changing, or not?
Sorry about the late response. Amol >> I have that going. I want to save directly back to a blob as if it were a filehandle. Thought that was clear in my question.
I have decided that this is almost impossible with a web application without writing some kind of client interface for each and every potential file type - word, excel, pdf, graphics, etc...
I am using Java to develop an application, it needs to manage the file on the computer. The application have the ability/function to delete the file on the system. But I want to check whether the selected file is using/reading by another application or not first. Because I don't want to delete the file which is reading/using. How can I do so?
Maybe you could use tryLock()?
On Windows, you can't delete files which are in use ("locked"). Java itself doesn't offer an API to check.
If another application is using the file or actively reading it, then provided that application has done its job correctly (opening the file with a read lock), you won't be able to delete the file -- you'll get an IOException (specifically, a sharing violation). Catch the exception to know whether there was a problem.