I'm designing a new application in JSE which I want to internationalize.
I've never done such an application. I'm looking for the best practices about the internationalization. The application while be writing the translated data in files or DB. I've searched about best practices but I didn't found anything about my main question(the first one).
Should I put all the internationalization data in some layer or next to the object they are about ?
Could I directly use the properties files as a kind of enum to do a switch case ?
Or can I reverse engineer the data catched and know the default internationalize value and work with it?
I did encounter several strategies. I would start with a properties file.
One factor is that the data must be professionally maintained:
keep it in version control.
keep a version number for us humans, "1.0.23"
keep the texts ordered and nice, to help translation.
keep a second properties file with a glossary for consistent translation.
Undermore I did see generating properties or java ListResourceBundles from DocBook XML, Excel, translation memories. And yes, database.
Maintenance of data must be done careful, as several different parties will use the text at different times.
Programming tools, consistency checks and preparing data, communicating are tasks not to neglect.
Properties files are not entirely ideal, but IDEs have generally some support for them.
Set up everything for UTF-8, though take notice that properties files use ISO-8859-1, but you can use \uXXXX escaping or do a encoding conversion in your build process. ListResourceBundle java sources, generated than, would be an alternative.
I have 46000 xml files that all share a common structure but there are variations and the number of files makes it impossible to figure out a common xml schema for all of them. Is there a tool that may help me to extract a schema from all these files or at least something that may give me a close enough idea of what is mandatory and what is optional?
Preferably, of course, a schema according to some standard or a DTD.
And, as I work entirely in Linux, a Linux tool or a program that works in Linux is OK. I am quite fluent in C, Java, Javascript, Groovy, Python (2.7 and 3) and a number of other languages.
Looking deeper into the problem and after scanning other posts I found out that inst2xsd is the tool for this kind of tasks.
In Android applications, resources are specified in xml documents, which automatically are built into the R class, readily accessible within the source code as strongly typed.
Is there any way I could use a similar approach for a regular Java desktop application?
What I'd like to accomplish, is both the removal of strings from the code (as a separation of "layers", more or less) and to make it easy to add support for localization, by simply telling the program to choose the xml file corresponding to the desired language.
I've googled around a bit, but the things I'm looking for seem to be drowning in results about parsing or outputting xml, rather than tools utilizing xml to generate code.
Eclipse's message bundle implementation (used by plugins for example) integrates with the Externalize Strings feature and generates both a static class and a resource properties file for your strings:
http://www.eclipse.org/eclipse/platform-core/documents/3.1/message_bundles.html
For this integration to work Eclipse needs to see org.eclipse.osgi.util.NLS on the class path. From memory, the dependencies of the libraries it was available in were a little tricky for the project I used this approach in, so I just got the source and have it as a stand-alone class in my core module (see the comments for more on that).
It provides the type safety you're looking for and the IDE features save a lot of time. I've found no downsides to the approach so far.
Edit: this is actually what ghostbust555 mentioned in the comments, but not clear in that article that this isn't limited to Eclipse plugins and you refer to your resources via static members of a messages class.
I haven't seen any mention of others using this approach with their own applications, but to me it makes complete sense given the IDE integration and type safety.
I'm not sure if this is what you mean but check out internationalization- http://netbeans.org/kb/docs/java/gui-automatic-i18n.html
Are you looking for something that parses XML files and generates Java instances of similar "struct-like" objects, like JAXP, and JAXB?
I came across ResGen which, given resource bundle XML files generates Java files that can be used to access the resources in a type-safe way.
http://eigenbase.sourceforge.net/resgen/
(Disclaimer: I looked at a number of posts on here before asking, I found this one particularly helpful, I was just looking for a bit of a sanity check from you folks if possible)
Hi All,
I have an internal Java product that I have built for processing data files for loading into a database (AKA an ETL tool). I have pre-rolled stages for XSLT transformation, and doing things like pattern replacing within the original file. The input files can be of any format, they may be flat data files or XML data files, you configure the stages you require for the particular datafeed being loaded.
I have up until now ignored the issue of file encoding (a mistake I know), because all was working fine (in the main). However, I am now coming up against file encoding issues, to cut a long story short, because of the nature of the way stages can be configured together, I need to detect the file encoding of the input file and create a Java Reader object with the appropriate arguments. I just wanted to do a quick sanity check with you folks before I dive into something I can't claim to fully comprehend:
Adopt a standard file encoding of UTF-16 (I'm not ruling out loading double-byte characters in the future) for all files that are output from every stage within my toolkit
Use JUniversalChardet or jchardet to sniff the input file encoding
Use the Apache Commons IO library to create a standard reader and writer for all stages (am I right in thinking this doesn't have a similar encoding-sniffing API?)
Do you see any pitfalls/have any extra wisdom to offer in my outlined approach?
Is there any way I can be confident of backwards compatibility with any data loaded using my existing approach of letting the Java runtime decide the encoding of windows-1252?
Thanks in advance,
-James
With flat character data files, any encoding detection will need to rely on statistics and heuristics (like the presence of a BOM, or character/pattern frequency) because there are byte sequences that will be legal in more than one encoding, but map to different characters.
XML encoding detection should be more straightforward, but it is certainly possible to create ambiguously encoded XML (e.g. by leaving out the encoding in the header).
It may make more sense to use encoding detection APIs to indicate the probability of error to the user rather than rely on them as decision makers.
When you transform data from bytes to chars in Java, you are transcoding from encoding X to UTF-16(BE). What gets sent to your database depends on your database, its JDBC driver and how you've configured the column. That probably involves transcoding from UTF-16 to something else. Assuming you're not altering the database, existing character data should be safe; you might run into issues if you intend parsing BLOBs. If you've already parsed files written in disparate encodings, but treated them as another encoding, the corruption has already taken place - there are no silver bullets to fix that. If you need to alter the character set of a database from "ANSI" to Unicode, that might get painful.
Adoption of Unicode wherever possible is a good idea. It may not be possible, but prefer file formats where you can make encoding unambiguous - things like XML (which makes it easy) or JSON (which mandates UTF-8).
Option 1 strikes me as breaking backwards compatibility (certainly in the long run), although the "right way" to go (the right way option generally does break backwards compatibility) with perhaps additional thoughts about if UTF-8 would be a good choice.
Sniffing the encoding strikes me as reasonable if you have a limited, known set of encodings that you tested to know that your sniffer correctly distinguishes and identifies.
Another option here is to use some form of meta-data (file naming convention if nothing else more robust is an option) that lets your code know that the data was provided according to the UTF-16 standard and behave accordingly, otherwise convert it to the UTF-16 standard before moving forward.
For a current project the decision has to be made whether to use XML and an XSL-transformation to produce HTML or to directly use HTML-templates.
I'd be interested in arguments for or against the XSL-approach. I understand that in cases where you have to support many different layouts, an XSL-solution has a lot of advantages, but why would you choose it in those cases where you only have to support one target layout?
Edit: We're talking about Java here.
XSLT is a functional programming language and you can use it to create frontends as rich as any templating system. However, you shouldn't — you and your team will go insane.
Both options present the opportunity of transforming objects into a presentation form in a logical sort of way. XSLT is best suited for creating more XML, which might lead you to believe that it's a perfect candidate to use to create XHTML. However, creating XHTML shouldn't be the primary goal — Creating a user experience is. Don't concern yourself with the medium.
Two significant drawbacks to XSLT concern the syntax: Your templates, and the templates that they include, and the templates that those templates include will all be gigantic and verbose. Second, you'll have to do a lot of functional programming, and less-experienced engineers may be confused and terrified when they encounter a recursive template with an accumulating function parameter instead of a simple for loop.
If you're attracted by the beauty of transforming logically-constructed, valid XML entities, consider instead a type-safe templating system that transforms beans instead. Check out Google XML Pages, and create logically-organized, type-safe templates that will be easy for future engineers to pick up and extend.
I created an XML/XSLT-driven UI for an enterprise product about 5 years ago. We're still using it, and I can now look back on my experience and see many pros and cons:
Pros:
XSL is a powerful declarative language, useful & fun for experienced developers, and transforms can do pretty amazing things in a few lines of code
XSL is designed for use with XML, so if your data is already XML then it makes a lot of sense
Separation of concerns (rendering vs. data) is better than many template languages
XSL-based rendering can be easily "subclassed". By that I mean: let's say you have data class A with associated template A.xslt. For class B derived from A, you can easily create B.xslt with only the small differences, and include A.xslt for inherited behaviors. This makes it less succeptible to breaking due to changes in A.xslt.
The above point also gives you the power to do overrides. For class A with associated A.xslt, we can easily switch the associated template to A-custom.xslt, which is a few small changes plus inheritance of A.xslt. We can do this on the fly in the field and again, the benefit is that A-custom.xslt is only a few lines, not an entire modified copy of the original A.xslt. The small footprint means it's more likely to work with multiple versions of A.xslt.
In .NET 2.0, XSLT is compiled and becomes very fast. There may be similar tech for Java. (Most template languages do this now too.)
In .NET, it's possible to create an "Object XPath Navigator", which lets you transform your data objects without having to convert them to an XML object. Again there may be similar tech in Java
XSLT is smart about HTML & handles escaping, white space issues, etc. well
Cons:
XSL is a powerful declarative language, confusing to newer programmers - and fewer people know XSLT well
XSL is verbose. XML is often verbose too.
XSL transforms are probably slower than "native" templates. Even when compiled there's still more state overhead to XSL than most template languages
It's hard to pass parameters to XSLs, you have to either send them in line with your data (forcing you to create extra XML) or via system-specific methods (which may also involve constructing XML data)
If you don't have an ObjectXPathNavigator or equivalent, you'll incur significant overhead when turning your data objects into XML for transformation
Depending on the capabilities of your transformer, you may also incur buffering overhead as you transform into a string buffer and then send that string to the output device
The more advanced your XSLT usage, the less likely it is that your tools will support you (specifically as you start to use includes or faster ways to pass XML data in)
I'll try to update as I think of more issues. I think that looking back now, my verdict would be to stick with a common template language. What were once big issues when I selected XML/XSLT have now been addressed by newer and more mature revisions of the major template engines. We do still benefit greatly from the ability to inherit .xslt files, which is something most template engines don't do well. But in the end the value of having lots of developers providing examples is far greater (compare ASP.NET answers vs XSLT answers on StackOverflow, for instance.)
Hope that helps!
I've done significant development using XSLT and it has been both tremendously successful and a complete failure at two different sites.
A few thoughts before a conclusion:
I don't think anyone would argue that XSLT is far more powerful than a template parsing engine, it's a functional language.
Although it's not as widely adopted as most procedural languages, it's still a real language that's being used out there for actual projects, people can be hired already with knowledge of XSLT and it's a transferable skill for your current staff.
XSLT has also been around for a while now, the implementations are mature, I'm sure this is the case for long running templating engines (like Velocity) but newer engines may be less robust.
Whatever template language you decide on it's unlikely to be as well documented as XSLT. Check out any of the Michael Kay Programmer's reference series for an example on how to do a great reference book.
Tool support is generally very good ... if you have a budget. XMLSpy and Stylus Studio have both been very useful for me in the past.
XSLT is not only hard but, more importantly, different. Most people are not Computer Science graduates formally trained in functional programming. The majority of programmers will write XSLT in a procedural style which will not harness any power of the language and give you a maintenance headache.
XSLT transforms can be slow and can take a lot of memory. You may have problems if you have a stylesheet with a large XML input.
I love XSLT but whether you should use it or not comes down to a few points:
Are you committed to XSLT? Do you have serious in-house expertise in XSLT? Are you prepared to get some?
Is your data in XML? Does it make sense in XML? Do you have someone in-house who loves your data enough to make sure it's well structured and there's always an appropriate schema?
Unless the answer to those questions is yes and you have complex data that requires a complex rendering process, I wouldn't consider using XSLT ... especially if there's no experience in the team. Bad XSLT is much, much, much worse than a bad template.
However, it can render complex data in a maintainable fashion which would be impossible using many of today's templating engines.
Going the XSL way will future-proof your application. Meaning, if you decide in the future to add more templates with different layouts you will be able capitalize on those advantages. In my current project we save off the XML used (in an XMLType or CLOB) and allow other applications to access the data and XSL templates to generate documents via a web service. This was an after thought of the original design that was super easy to implement due to our decision to use XML/XSL.
XSLT has the advantage of being able to also produce output in other document types (i.e. pdf) and pdf output is very likely nowadays. XML/XSLT does also separate data from the view.
When we have done XSLT in the past, it was to allow the ability to extend our product. The output remained the same, only the presentation layer needed to change. This allowed us a lot of flexibility when we had clients that wanted to "customize" their UI, since all we needed to do was replace the XSLT file. If you foresee needing to make a lot of those kinds of changes, XSLT might be your answer.
However, as stated above, the XSLT syntax and functional programming mentality can make it difficult to effectively produce templates. We found that we liked to stick to the tricks that we learned and when we had client requests that fell outside of what we already knew, no one wanted to volunteer for the ticket. Usually someone eventually figured out how to do the task and our "bag of tricks" got larger, but it was often very cumbersome to figure out new things.
If you don't foresee change the UI ever, or at least not much, XSLT may not be worth the extra effort.
Please don't use XML/XSLT for web front-ends. I was in projects like this and it's horrible. Often you have to first produce the XML from objects or something similar, which doesn't make sense. A second point is, that there are so many good HTML editors out there for free, but I've found none for XSLT. So editing complex XSLT is no fun. I would recommend to go with HTML templates and a common template engine.
Depending on your application, having an XML layer that is then transformed to XHTML via XSLT also meens, that you can write easy WebServices to the XML layer - allowing your customers to consume your sites data...
Having the XML sent to the browser with a transformation link (forgot the exact syntax...) also meens less bandwith needed, as the XSLT file will stay the same and you only need to pass the raw XML it is built from - sort of like using an external CSS style sheet instead of adding the style attributes to your markup ;)
I think you need to examine what the source of your data will be. As mentioned by boris callens earlier, if the you are pulling from a database you will have to transform first to XML, then apply your transformations. Should the data source be RSS or the like, then XSLT is a natural choice.
XPATH and XSLT has a high learning curve and functional programming can be daunting to get your arms around. In time crunch this may not be the right choice.
For front end work JSON has a lighter payload, and is readily supported by jQuery and other Javascript libraries. You may want to consider JSON as the data protocol as the jQuery library is far more accessible to developers and the time to productivity with the framework is far less than with XSLT, embedded Javascript in tags, awful syntax and all the other minutia that come with XML/XPATH/XSLT on the front end.
Keep it simple. That's a principle that one gets to appreciate more and more.
Velocity or Freemarker are incredibly flexible and versatile. Your code base will be clear, easily understandable, and it will run much (much) faster than the X monstrosities.
http://fishbowl.pastiche.org/2002/02/12/xslt_is_the_spawn_of_satan/
I see how the XSL approach can be handy if your data is already XML.
But usually it isn't. It's somewhere in a database, needs to be generated on the spot or comes from some service.
Creating XML from this source to then be able to create HTML from that XML is useless in my opinion. I would stick with (X)Html templates.
In contrast to HTML, there are a lot of XML tools available if you need to do parsing and processing of the templates in any way. So you should choose XML to get the benefits of using tools and libraries for XML.
However, that said, it may just be that XHTML fits your needs, since this gives you full support of XML tools and libraries while still being normal HTML which is correctly processed by modern web browsers. If you need to do post-processing of those later on, you can still apply XSLT to the XHTML data.
I've used XML & XSLT in a previous project, financial web sites, and it worked well for us, but:
We had multiple customers, which
varied the number of outputs we had.
We could replace the XSLT stylesheet
and this made changes to the site
easier to manage for the developers
We had a specialist web editor on the team. We gave them example XML & they could edit the stylesheets directly
If there were ever any wording changes that needed to go onto the website yesterday ( it was a bank, this happened surprisingly often), we could just deploy the new XSLT without redeploying the entire site.
Multiple different output formats were needed. We used FOP for transformation to PDF, which is based upon the same sort of technology, so wasn't too hard for us to understand :-)
The main reason I see for using XSLT is if you have multiple sites all based upon the same XML, but requiring different HTML output.
XML + XSLT are really cool. You have the ability to output many types of target formats in the future.
But ne aware of embedded HTML in the XML. Firefox XSLT doesn't support "disable-output-escaping". See Bugzilla.
We use XSLT to generate html in our content management system and it works just fine.
Some hints: Don't try to generate all the page at once from one big hairy XML, you'll go insane. Use the HTML template (plain text/html file with styles, decorations and basic markup) with embedded markers (like, <!--MENU-->, <!--CONTENT-->), and replace markers with xslt-transformation of appropriate data.
Having said that, I doubt you really need xslt if you only going to have one layout, forever.