I am using docx4j to load, manipulate and save Word files. Everything works perfectly but there is one thing i don't know how to implement it.
What I want is something like a version control - that means if you save a document it shall be possible to recover a earlier version of this document (e.g. by saving only the delta). Maybe you can describe it that is should be something like SVN or Git where you can go back to an earlier version of your files.
The problem is that i do not know any possibility to realize that. So I hope that anyone of you can help me. It would be fine if anyone at least know a package or something else that can do this with files in general and not especially with the docx Files.
Thanks for your help!
Edit: I am sorry that my question was imprecise. This was my first post here, in future i will improve ;)
JGit is a Java implementation of Git that will work with few dependencies. Similar libraries exist for SVN and CVS. Home-brewing a version control system is almost certainly a terrible idea, given the existence of good-quality solutions!
If you'd like some pure java implementatoin for document versioning, maybe you could go for: Jackrabbit
Similar questions have been already asked before. The 1.st answer (marked as correct one) on this question goes for Jackrabbit as well: Using a version control system as a data backend
I think you should use Git for this, I found a Java API called JavaGit, so you can have easy access the repository.
With Git you can have a local repository where you can commit files and switch versions. If you need it you could also push and pull the data to a remote location.
Better use JGit like Gian said!
The simplest possible way would be to use tools diff and patch. They were used as a core of CVS. I assume that you would like to run your application in Windows where they are not preinstalled. I don't know whether it would be easy / comfortable to use windows versions of this tools but you can always try to write similiar functionality on your own. Here you can find very good tutorial about finding differences between files and patching them: http://tuts.pinehead.tv/2012/09/18/introduction-using-diff-and-patch/ When you know the functionality it's quite easy to write something similiar on your own.
This can be a tricky thing to implement yourself, so I wouldn't recommend it.
I don't know much about your environment, but if you are able to use an off-the-shelf versioning repository, you'll save yourself much grief. You can try to use Git or SVN directly, which may be the simplest solution for your use case.
Since you're talking about MS Office files, however, you may be implementing some form of enterprise document management tool. In this case, the JCR specification is designed to provide access to files in a repository, with versioning and other metadata features. Here's the specification.
The Apache Jackrabbit project provides an open source implementation of this spec, as does the developers version of Alfresco.
Picking the right solution will really depend on what your users are trying to do with these files, what your deployment environment looks like (don't try to host Git on Windows, k?), and how custom your current codebase is (standard Servlet container? Java EE? home-rolled?).
Good luck!
Related
I'm writing java swing app. I need my app connect to server CentOS 5.5, using username + *.ppk file (I don't have password). Then, my app execute some command line on this server.
Is this possible ? What library is best for it ?
There is a number of libraries that support what you're trying to achieve in different ways.
Connecting to an SSH server via Java is no big thing anymore these days.
Those are some libraries that you might consider:
Ganymede
http://www.cleondris.ch/opensource/ssh2/
Ganymede was made by some students at the ETH Zurich and works quite well. I personally use it in a project that runs on a very old machine using Java 1.3. It doesn't require anything besides a JRE. It is, however, not very active anymore. There is that company that seems to support it (Cleondris), but I wouldn't know how reliable they are. Doesn't matter much though since it's open source anyways. If you need to run your app on old java versions or need to know, that your app runs withou the Java Cryptography Extension (JCE), you could chose this.
JSch
http://sourceforge.net/projects/jsch/
JSch too is a mature piece of software and just works. If you've ever used ant to do SSH/SCP related tasks, you probably know it already. It's always a bother since you have to provide it to ant manually :-)
The project is well maintained, as it seems and widely used. I used it in a lot of modern UI/Batch applications and was/am always happy with it. It does use JCE though and I did once experience problems with that (on an older JRE, but still). If you plan to distribute your software to clients unknown to you, this might be a problem. JCE needs stuff installed / configured inside the JRE installation itself. Probably works 99% of the time, but still...
SSHTools
http://sshtools.sourceforge.net/
Never used this one but heard good things. May be worth a try.
Converting ppk to OpenSSH format using Java
As this is obviously possible, it's only a matter of implementing it. Fortunately for you, there are actually multiple implementations around. It might even be implemented in one of the suggested SSH libraries, but I didn't check.
A quick google search revealed two choices to me:
trilead-putty-extension
https://github.com/kohsuke/trilead-putty-extension
Seems to me like a very nice choice. Even though it's an extension to Trilead SSH library (which, it seems, isn't available anymore), it's not a lot of code and could easily be integrated into an existing project. There is one class that does the work and can convert a ppk key into a openssh one. String to string, so no surprises there. Should really be a piece of cake.
I don't know what happend to Trilead. The company doesn't mention it anymore on their website, but it certrainly existed at some point (http://techtavern.wordpress.com/2008/11/13/about-trilead-ssh-open-source-project/).
By the way: The guy who wrote it is the one who also wrote Jenkins/Hudson. http://kohsuke.org/
"ChillKat" Java Library
http://www.example-code.com/java/ssh_ppk_to_pem.aspn
Well... this just as an alternative. Doesn't seem worth the effort and overhead to download a "multi-purpose" library just for that. You could maybe extract the relevant parts or let yourself be inspired by it. Maybe the trilead extension doesn't work and you have to pick this one, but I wouldn't consider it first choice.
You can of course always convert the .ppk file manually, as explained here: http://www.lmolnar.com/geek/how-to-convert-puttys-private-key-ppk-into-opensshs-private-key-format-in-linux/
And other places, I guess. There is the graphical tool puttygen too, which is included in putty-installer or downloadable standalone via the putty website (http://www.chiark.greenend.org.uk/~sgtatham/putty/).
Would you like to know more?
Check this: http://linuxmafia.com/ssh/java.html or write a comment.
If converting the .ppk to a less proprietary format (i.e. .pub rsa or dsa) is an option, then give a try to puttygen (usage: "puttygen keyfile.ppk -o id_rsa -O private-openssh") from the putty-tools package.
Then use SSHTools, a java API for SSH (and more)
One of options is to use SSHBlackbox package of our SecureBlackbox product. It supports loading of Putty keys and full scope of SSH-related functionality (SFTP requires SFTPBlackbox package). SecureBlackbox comes with extensive samples and support.
The current JSch version does not support *.ppk files,
but JSch can use those files by using jsch-agent-proxy via Putty's Pageant.
Install and open puttygen
Click on "Load an existing private key file"
Click on menu item "Conversions" -> "Export OpenSSH key"
Save file, and use this in your Java app
I am looking for good and practical resources that will help me use the Ant APIs effectively. The project website just gives the documentation of the API which is not useful at all. Very few websites seem to give very brief tutorials on the subject.
Is there some resource I am missing out on? How can I use the Ant APIs for simple tasks, without spending hours browsing through them and looking at source code?
Thanks.
(Answers to previously asked questions not helpful - How can i use Apache ANT Programmatically )
As it turns out, the lack of good resources on using the Ant API, is known and intended.
The bottom paragraph of this article from the Ant says -
The question you are probably asking yourself at this point is: How would I know which classes and methods have to be called in order to set up a dummy Project and Target? The answer is: you don't. Ultimately, you have to be willing to get your feet wet and read the source code. The above example is merely designed to whet your appetite and get you started. Go for it!
So this seems to be the only way to make best use of the API.
..Java program to programmatically build source files
If compiling/Jarring is all you need and you can run it in an SDK (as opposed to a plain JRE), look to the JavaCompiler class for compilation. Then use the Jar related classes to build the Jars.
All J2SE. Ant not included, Ant not required.
There is no better manual to understand ANT than : http://ant.apache.org/manual/index.html
I am not sure if you've gone through this link that explains in detail about creating a task. A word of caution, If you're new to ANT, there is no easy way to jump on this tutorial. Better to learn the basics before you come here. Refer above link for a good starting point.
I am planning to build a simple document management system. Preferably built around the java platform. Are there are best practices around this? The requirements are :
Ability to upload documents
Ability to Tag documents
Version the documents
Comment on documents
There are a couple of options that I am currently considering. The first option would be a simple API on top of SVN or CVS and use a DB backend to track tags, uploader, comments etc
Another option is to use the filesystem. Version the documents as copies in a versions folder and work with filenames.
Or, if there is an Open non GPL'ed doc management system, we could customize it to our needs and package it in our application. Does anybody have any experience building something like this?
You may want to take a look at Content repository API for Java and the several implementations (some of them free).
Take a look at the many Document Oriented Database systems out there. I can't speak about MongoDB or any of the others, but my experience with Couchdb has been fantastic.
http://couchdb.apache.org/
best part of it is that you communicate with it via a REST protocol.
The best way is to reuse the efforts of others. This particular wheel has been invented quite a bit of times.
Who will use this and for what purpose?
I'm involved in a project that, among other things, involves storing edits and changes to a large hierarchical document (HTML-formatted text). We want to include versioning of textual changes and of structural changes.
Currently we're maintaining the tree of document sections in a relational database, but as we start working on how to manage versioning of structural changes, it's clear that we're in danger of having to write a lot of the functionality that a version control system provides.
We don't want to reinvent the wheel. Is it possible that we could use an existing version control system as the data store, at least for the document itself? Presumably we could do so by writing out new versions to the filesystem, and keeping that directory under version control (and programmatically doing commits and so forth) but it would be better if we could directly interact with the repository via code.
The VCS that we are most familiar with is Subversion, but I'm not thrilled with how Subversion represents changes to the directory structure -- it would be nice if we could see that a particular revision included moving a section from Chapter 2 to Chapter 6, rather than just seeing a new version of the tree. This sounds more like the way a system like Mercurial handles changes to the structure.
Any advice? Do VCS's have public APIs and so forth? The project is in Java (with Spring) if it matters.
Maybe you could use a JCR (JSR-170) compliant repository like Jackrabbit instead. To me, what you're describing is exactly what JCR is for. Have a look at this article.
You can certainly program SCMs via APIs. Check out SVNKit for Java and Subversion, or JGit for Java and Git. Mercurial doesn't appear to offer such an API.
Whatever you do, wrap up your implementation in a suitable API, so you can swap one SCM for another, or maybe bin the concept of an SCM at some stage in the future. It may well be a pragmatic solution to your problem, however, and worthy of more investigation.
Try http://svnkit.com/ for Subversion.
Here you have a pure Java SVN lib SVNkit it can be used by Eclipse SVN integration so it should be fairly stable.
SVN and CVS are two very different systems that aim to address the same basic issue - source control.
They both work in distinct ways, so it's probably difficult to deal with them exactly the same.
What I'm wondering is, would it be conceivable to develop a programming library or API that exposes the same interface, but under the hood, can be set up to work with either an SVN or CVS repository?
I'm aiming to develop such a library in either .NET or Java (most likely .NET), but I wanted to get some thoughts on how feasible this would be, and if there's a better way to approach the problem.
The context of this is: I'm building a web-based service that will involve source control hosting, and I want to support both SVN and CVS so as to serve the largest amount of developers possible.
Personally I would ignore CVS for a new product. My feeling would be that the enormous extra effort to coerce it into looking like SVN would be better spent on other other stuff. I don't know your market, so I might be wrong, but that's got to be worth thinking about.
The MSSCCI API does something very similar:
http://alinconstantin.homeip.net/webdocs/scc/msscci.htm
The MSSCCI tries to make all source controls look the same from the perspective of the IDE.
viewvc lets you browse svn and cvs repositories. maybe there is an existing product which will already do what you want?