It's been about 6 years since I had to do any Java programming, and even longer since I had to do any notable amount of Java programming. While I remember the language, I was always weak on all the other things, such as all the tools for building programs and such. In fact, I've forgotten more than I remember - and I was self taught in the first place.
In the past I based my organization of code on what I had seen in some open source projects, so I had directories set up with something like com/mybiz/util and com/mybiz/network and so on. I'd put the source code for the classes in the appropriate directory and make sure it was in the package that matched that path. Then if I had to change the code (like for a bug fix or to add a new routine in an existing class), it was easy for me - change it and recompile the class. As I recall, imports for the classes in the root directory for my project (it was all tied together) to use these classes were no problem with that setup.
Then someone told me about Eclipse, but the biggest thing I remember doing was refactoring in it. Until then, my IDE was a console window and a text editor.
So I still have a lot of classes in that hierarchy - com/mybiz/util (and so on). But now I'm using this code for personal libraries, so it's in com/tango/util and com/tango/network and such. I've having to make changes here and there to code to make it more universal and to remove stuff that was specific to the business for one reason or another.
I want to use these classes as libraries for my projects in Eclipse now. I'd rather not just compile and put them all into a jar, since many of the classes are still being fine tuned and need recompiling. I'd rather just be able to tell Eclipse, "Use this bundle of source code in the "com/tango..." directory tree and then just use something like "import com.tango.util.FileUtils" in my source code.
Even more, I'd like to be able to specify this as a library or some kind of available source code or resource in Eclipse so it's easily added (or added by default) to each project I create.
Can I do this? Or should I be looking into something else or another way to handle it instead? Again, I'd rather just have the source code included, since it's still being changed around and being recompiled.
For the refactoring "magic" you want to use Eclipse needs to know all source files to execute, so you have to have all your source code added into an Eclipse Java project.
However, if you want to have a set of classes that are available for multiple projects, nobody stops you from creating multiple projects, and setting up dependencies between them. The easiest way to achieve this is to add a dependency in the New Java Project wizard (be careful not to press the finish button after setting up the project name but use the Next button where you can add existing Java projects into the build path).
If all your source code is available in either a single, or some interdependent Eclipse Java projects, then Eclipse will take care of compiling all the classes. Usually, Eclipse is intelligent enough to only recompile what needs to be changed, so this process is really swift (at least most of the time).
I hope this answer is helpful enough - if not, feel free to ask for further information.
Edit: Adding information about Java libraries support.
If your "library" project does not change, but you have a jar for it (typically a case of an externally downloaded library), Eclipse allows you to define User Libraries - libraries that can be added to build path of a Java project. To create such a User Library, open Preferences, go to the page Java/*Build Path*/User Libraries, where you can define libraries that consist of one or more jar files.
However, if you are developing your own libraries, and your project does not go into a gigantic size (e.g. several million lines of code), I recommend adding the library project as source into the Eclipse workspace, as in my experience that is easier to maintain in the long run.
First, I would suggest using IntelliJ (in my opinion it's much better than eclipse) but it is very possible to do this and simple as well. So to save time lets pretend all the classes you need in the future library are Network.class, FileUtils.class, and Helper.class. First make a new folder on your desktop called My Libraries. Right click on it and hit Send To, then Compressed Zip Folder.:
Once that's done drag your class files into the folder.
Open up Eclipse and choose a workspace. Once you've done that, you should show up with the default Eclipse screen. Now hit the File tab and hover over New, then go to Java Project.
You will show up with another screen. Enter the name for your project and click Next. Hit the Libraries tab and then click Add External Jars.
Now navigate to your Compressed Zip and click Open.
You now have your library added.
Here is a little ASCII Chart so you can remember:
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Folder -> Class Files -> Compressed Zip -> Eclipse -> New Project -> Next -> Libraries -> Add External Jars -> Compressed Zip (Library)
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Related
I'm currently trying to write my first own library. It's just for testing, I want to find out how libraries are written, compiled, distributed and used in order to prepare for some upcoming personal projects.
Yet, what really causes me to wonder, is why exactly my Javadoc isn't compiled with the Library. I know that comments and annotations are not compiled, but for example the JDK (which is basically a huge library) comes with a working doc as well.
I've tried to compile a JAR (libraries aree normally JARs, right?) from not the compile output, but the sources (so I had a JAR of .java files), but this failed to be included in IntelliJ. I could add it as an external library, but neither did it show up in my explorer, not could I import or use any of my classes.
I know there must be a mistake somewhere here, all libraries I've ver used, whether it was Java, C# or whatever else always came with a working documentation (IntelliJ shold show that on mouse hover), and I'd like to know how to correctly build a library that I can share with a team partner, so he just needs to download it, add it as a library in IntelliJ and has all the functionality, but also the documentation.
Thanks to everyone in advance!
Because it isn't needed, and would bloat the file size of the executable. If you have a library in C or C++, the documentation may be bundled in a zip file, but you won't find it in the compiled .so or .dll. One just holds the binary and resources needed for the project. The .jar is equivalent of that- it's the compiled output. Documentation is hosted/downloaded separately.
When you download the JDK, you're not just downloading a giant .jar. It includes other things, like documentation in the download.
I'd like to know how to correctly build a library that I can share with a team partner, so he just needs to download it, add it as a library in IntelliJ and has all the functionality, but also the documentation.
The short answer is that you provide your team partners with your project source code as well as the binaries. They then can configure their IDE (Intellij, NetBeans, Eclipse, whatever) with the location of the source code and the IDE will be able to extract the javadoc comments on the fly and render them as requested.
Sharing the source code also has the additional benefit that your partners can debug their (and your) code better. By themselves, javadocs are rarely sufficient for debugging complicated problems.
Alright, if everyone ever has this probelm again, here's a complete tutorial:
As #Gabe Sechan already said, the Doc is not compiled into the JAR for some valid reasons. Instead, I recommend you to add the following to your JAR:
module compilation output
content of "src" directory / alternatively: module sources
Build --> Artifacts --> All Artifacts.
Now, if you add your library JAR into a project, it will show "Classes" and "Sources" in the right tab, as IntelliJ automatically recognizes you've bundled both into the JAR.
Now, IntelliJ should show your documentation, as it lives within the source files.
If, for some reason, IntelliJ switches from its "fancy" documentation popup to unformatted plain text, proceed as follows:
Navigate to File -> Settings -> Advanced Settings, and in the 5th block, where it says "Documentation Components", just tick everything you find. That's gonna fix it.
Thanks to Gabe Sechan again, your answer helped me to understand what won't work, and finally I've found a way to make it work myself.
So I took a Coursera course that had me work with external libraries. Two .jar files which most of the weekly projects depended upon.
I'm not entirely sure how eclipse compiles and runs the files, and how it links to these external libraries -- what is the proper way of organizing this? Do I put a copy of each .jar file in each project directory?
Is there another, cleaner way that I should be organizing this?
Thanks --
As a beginner programmer it is OK to put it in each project. But consider that this is ongoing work and at some time in future you want to upgrade to a new version of these external libraries. Then you would have to copy it everywhere.
Instead another option is to store them in one place and add it in classpath in each project. Now you have only one copy of it, which is always better.
Now, if and when you do get a new version then the file names might change, so you will still have to change the classpath of each project.
But I advise you to worry about these and other such problems later. For now, focus on programming related problems rather than configuration.
If you want to maintain your libraries professionally in a formal manor then you're better of using a build tool like Gradle of Maven.
I'd suggest you to use Gradle to maintain the project since it has a whole lot of useful build tools available to you to use. Eclipse has a Gradle plugin available which allows you to use Gradle projects with it. See link below.
To give you a idea of how Gradle is used professionally. Android uses it by default to maintain their projects now. So Android java projects uses the Gradle build tool to maintain its library sources, compilation processes and such.
The difference between a Gradle project and a normal java project is that a Gradle project has a list of pre-defined scripts available to you which fetches the libraries, compiles them and prepares them before exporting the final bundle (jar). So really all Gradle does in before hand is fetch the libraries and prepares the specified tools before compilation so you won't need to mess with them your self. It prepares your project directory and remotely maintains your libraries so if they're available from a repository then it'll make sure to prepare them appropriately in before hand and setup your projects directories.
So really the difference you'd physically notice is that instead of using the default Eclipse export button to create your bundle (jar) you'd instead use a button from the side menu which the Gradle plugin adds and also you'd cleanly list the libraries in a structured order in a file that gets added to your project root.
If you want to get a basic understanding of how it works and really want to start to proffesionally or formally structure your project then try to create a very basic android app in Android Studio. see link below
If this isn't what you want at all and don't want to take it to this advanced level yet then adding the library bundles into some kind of lib folder that's located in your project root is properly best practice.
If you wonder why? Well basically different projects might use different versions of the library which may add or remove support to them. So to keep the versions consistent and make sure to have the right version available to you, you have the direct source near the project it self.
Here's some useful link:
http://www.vogella.com/tutorials/EclipseGradle/article.html
http://developer.android.com/sdk/index.html
Background:
Here at the office my group uses a common linux environment where we do our code development. Our code is kept in CVS. The latest releases of our various libraries are kept in a specific directory (ie /data/group_projects/lib). Our Makefiles/Ant builds all specify what libraries are needed. We use autoconf to create the makefile after checkout for most C/C++ projects. We've just got Eclipse (3.4) installed and are planning to incorporate it into our workflow.
Problem:
So, when I check out a project from CVS through the Eclipse interface and then I have to set up all of the library paths (and include paths for C/C++). For some of our projects, this could be a lot of work. Is there a good way to save these paths along with the code when I check it back into CVS?
Ideally, when the next person checks out the code in Eclipse, the paths (and anything else they might need) will automatically be set up and they will be able to compile straight away.
Efforts:
I know that the include/lib path info is kept in a .cproject or a .classpath file (C/C++ or Java respectively). I thought I could export this info through Export -> Preferences. The resulting epf file doesn't have any path data in it unfortunately. I tried directly adding the .cproject file to one of my projects (so I could then put it into CVS) but Eclipse really doesn't seem to want me to do that.
I am quite new to Eclipse (esp using CDT), but maybe the necessary path info can be pulled out of build.xml/Makefile automatically by Eclipse? There seems to be a bit of a disconnect in Eclipse between the buildfile/makefile and the jar/include files that the IDE uses for checking your code as you type it. Maybe I am missing something?? I'm planning to put some serious time into researching Eclipse over the next few days so hopefully the inner workings will become much more clear to me.
I've asked the guys here at the office but no one is much of an Eclipse guru. My searches haven't turned up much . . I did see a suggestion to add all external jars to Java -> Build Path -> User Libraries under Eclipse Preferences. For us, each user would have to set this up once but afterward all of our java libraries would be available to whatever project we decided to check out. Unfortunately, it doesn't seem as though I can do the same thing for CDT.
What would you suggest? Am I missing a setting or function of Eclipse? Or am I going about this the wrong way? Please let me know what you think. I'd really appreciate it. Thanks!
You simply need to share the .project, .cproject and .classpath files through CVS. You can do this from the cvs command line, or select then 'Team/add file to version control'.
You don't need to add these files to the project explicitly: they are inherently part of it.
Obviously, if you do this, you need to make sure they are location-independent.
See:
eclipse wiki
Safari books
I've done this in Eclipse, and it's not too hard. You have to check in the .project and .classpath files. There are one or two places where Eclipse doesn't correctly automatically check out the files when you want to edit them, so when you get a read-only error you have to go manually do it, but for the most part it works.
The paths need to be all relative.
If relative paths is a problem, you can also take advantage of workspace variables in Eclipse. The developer sets their workspace variables appropriately on their machine (e.g., OPENGL_INCLUDE_PATH ), and then in the builder you can set the environment to pass that path along.
I am using Eclipse 3.4.2 to develop my code. As part of my project definition I reference a utility library to which I have attached the source code. So far, so good - I can see that source when I bring up classes from the library and while I am debugging.
Now however I would like to make a change to one of the classes while still retaining all the features of the Eclipse Java editor (specifically things like tool tips and quick fix). These features seem to work when I'm viewing the source (I can CTRL+LClick through method names for instance), but it is read-only. On the other hand I can explicitly open the source file which will allow me to edit it, but I lose all of the "smart" editing features.
I've recently switched to Eclipse from IntelliJ where this was possible so I'm hoping it is in Eclipse as well. Note that although I could simply include the code as a project in my workspace, I'd really rather not. The workspace is already quite large and I don't want to further slow Eclipse down by adding projects I rarely would ever touch.
I am not sure I get your question right. When you add a precompiled library to your projects build path (the JAR) and attach source to this JAR, Eclipse will show you the source code when you click on a .class inside the JAR. The same goes for the debugger, which will also allow you to step through the code lines in the source, if the classes in the JAR were compiled with line number information.
Now what you seem to want to do is modify the classes inside the JAR (the source view is just an overlay which can even be off, if you attach a different version of the source), which is not possible, because they are wrapped up in binary form in the JAR archive - even though Eclipse is smart enough to display them individually.
I guess you would expect your changes to be hot-swapped into the running program by the debugger. This can only be done through a recompile once you finished your changes. Usually Eclipse does that automatically when you save a Java source file. As your source file is however not part of the workspace (or an external folder explicitly declared as Java source) - it will not do that recompile and swap.
I'd recommend to include the source of your external library as a project in Eclipse and not worry about performance too much - I work with 3.4.2 every day and my workspace has about 45 open projects with several 10.000 classes and millions of lines of code. I assign a Gigabyte of RAM to the Eclipse VM and have no problems with that on a Core2Duo 2.6GHz machine.
I'm soon going to check in the very first commit of a new Java project. I work with Eclipse Ganymede and a bunch of plug ins are making things a little bit easier.
Previously I've been part of projects where the entire Eclipse project was checked in. It's quite convenient to get the project settings after a check out. However this approach still was not problem free:
I strongly suspect that some Eclipse configuration files would change without user interaction (from when I used Eclipse Europa), making them appear as changed (as they were changed, but not interactively) when it's time to do a commit.
There are settings unique to each development machine as well as settings global for all developers on a project. Keeping these apart was hard.
Sometime if the Eclipse version was different from others Eclipse would get angry and mess up the project configuration. Another case is that it change the format so it gets updated, and if commited messes up the configuration for others.
For this specific project I have another reason not to commit the project files:
There might be developers who prefer NetBeans which will join the project later. However they won't join within the coming months.
How do you organize this? What do you check into versioning control and what do you keep outside? What do you consider best practice in this kind of situation?
At a minimum you should be check-in the .project and .classpath files. If anybody on your team is hard-coding an external JAR location in the .classpath you should put them up against the wall and shoot them. I use Maven to manage my dependencies but if you are not using maven you should create user libraries for your external JARs with with a consistent naming convention.
After that you need to consider things on a plug-in by plug-in basis. For example I work with Spring so I always check-in the .springBeans and likewise for CheckStyle I always check-in the .checkstyle project.
It gets a bit trickier when it comes to the configuration in the .settings folder but I generally check-in the following if I change the default settings for my project and want them shared with the rest of the team:
.settings/org.eclipse.jdt.ui.prefs - it contains the settings for the import ordering
.settings/org.eclipse.jdt.core.prefs - it contains the settings for the compiler version
In general I haven't noticed Ganymede modifying files without me modifying the project preferences.
I recommend to use maven so that the entire life cycle is outside of any IDE. You can easily create an eclipse project with it on the command line and you can use whatever you want, if it's not eclipse. It has it's quirks but takes out a lot of bitterness when it comes to dependencies and build management.
In our world, we check in the entire Eclipse project and the entire parallel but separate Netbeans project. Our motivations for this were entirely focused on "when I do a checkout, I want a functional configuration immediately afterward." This means that we had to do some work:
Create runnable configurations for each primary IDE (people like what they like). This includes main class, working directory, VM parameters, etc.
Create useful start up scripts for all of our relevant scenarios.
Create edited datasets that don't cause the checkout to take too much longer (it's a big project).
This philosophy was worth cash money (or at least labor hours which are almost more valuable) when our new hire was able to check out the project from Subversion into Eclipse and immediately run a functional system with a (small) real data set without any fuss or bother on his part.
Follow up: this philosophy of "make the new guy's life easier" paid off again when he changed IDEs (he decided to try Netbeans after using Eclipse for quite a long time and decided to stick with it for a while). No configuration was required at all, he just opened the Netbeans project in the same directory that Eclipse had been pointing to. Elapsed switchover time: approximately 60 seconds.
I only ever check in things are done by humans, anything else that is generated (whether automaticly or not) should be easy to regenerate again and is liable to change (as you've stated). The only exeption to this is when the generated files are hard (requires alot of human intervention ;) ) to get it right. How ever things like this should really be automated some how.
Try to port your project to a build system like maven. It has everything you need to get the same experience of the project on every machine you use.
There are plugins for just everything. Like the eclipse plugin. You just type "mvn eclipse:eclipse" and the plugin generates your entire ready to work eclipse project.
To give the answer to your question. Never check in files that are not being used by your project at any time in the development cycle. That means that metadata files like eclipse properties etc. should never be checked in in a SCM.
I like checking in the .project, .classpath, and similar files only if they will be identical on any Eclipse user's machine anyway. (People using other IDEs should be able to check out and build your project regardless, but that issue is orthogonal to whether or not to check in Eclipse-only files.)
If different users working on the project will want to make changes or tweaks to their .project or .classpath or other files, I recommend that you do not check them into source control. It will only cause headaches in the long run.
I use IntelliJ, which has XML project files. I don't check those in, because they change frequently and are easy to recreate if I need to.
I don't check in JAR files. I keep those in a separate repository, a la Maven 2.
I don't check in WARs or JARs or javadocs or anything else that can be generated.
I do check in SQL and scripts and Java source and XML config.
I'd suggest having the actual project files ignored by the version control system due to the downsides you mentioned.
If there is enough consistent information in the project settings that there would be benefit from having it accessible, copy it to a location that Eclipse doesn't treat as special, and you'll have it available to work with on checkout (and copy back to where Eclipse will pay attention to it). There is a decent chance that keeping the actual project files separate from the controlled ones will result in loss of synch, so I'd only suggest this if there is clear benefit from having the settings available (or you're confident that you'll be able to keep them synchronised)
In our case, we used to check in the project files (.project and .classpath) to make it easy for all developers to create their project workspace. A common preferences file and team project set were located in source control as well, so creating your workspace was as simple as import preferences and import team project set. This worked very well, but does rely on everyone having a consistent environment, any customizations would have to be applied after the basic workspace is created.
We still do this for the most part, but Maven is now used so of course dependency management is handled via Maven instead. To avoid conflicting information, the .project and .classpath were removed from source control and are now generated via maven goals before we import the team project set. This would easily allow for different environments, as you would simply need scripts to generate the IDE specific portions based on the Maven configuration.
PS-For ease of maintenance though, I prefer having everyone use the same environment. Anything else inevitably becomes a full time maintenance job for someone.
Netbeans 6.5 has an improved Eclipse project import which is supposed to sync changes from Netbeans back to Eclipse: http://wiki.netbeans.org/NewAndNoteWorthyNB65#section-NewAndNoteWorthyNB65-EclipseProjectImportAndSynchronization
Don't. Only check in the source code of your projects.
As a response to:
"There are settings unique to each development machine as well as settings global for all developers on a project. Keeping these apart was hard."
Eclipse offers a number of ways to keep local settings manageable: Java Classpath Variables (Java > Build Path > Classpath Variables) are one, 'Linked Resources' (General > Workspace > Linked Resources) are another http://help.eclipse.org/stable/index.jsp?topic=/org.eclipse.platform.doc.user/concepts/concepts-13.htm Creating a README that states which settings to set before building/running the project works pretty well in my opinion.
Now how to make sure your continuous build system understands the changes that were made to the eclipse settings, thats another issue... (I have a separate build.xml for ant that I keep up to date by hand)