How to get Eclipse to create bin/main and bin/test - eclipse

I want my Ant build to take all Java sources from src/main/*, compile them, and place them inside bin/main/. I also want it to compile src/test/* sources to bin/test/. I wan this behavior because I want to package the binaries into different JARs, and if they all just go to a single bin/ directory it will be impossible* (extremely difficult!) to know which class files belong where.
When I go to configure my build path and then click the Source tab I see an area toward the bottom where it reads Default output folder: and then allows you to browser for its location.
I'm wondering how to create bin/main and bin/test in an existing project without "breaking" Eclipse (it happens). I'm also wondering that if I just have my Ant build make and delete those directories during the clean-n-build process, that Eclipse might not care what the default output is set to. But I can't find any documentation either way.
Thanks in advance for any help here.

In Eclipse, you can only have one output folder per project for your compiled Java files. So you cannot get Eclipse to do the split you want (i.e. compile src/main to bin/main and src/test to bin/test).
You can, if you want, create two Eclipse projects, one main project and one test project, where the test project depends on (and tests) the main project. However, in that case, each project should be in its own directory structure, which is not what you are asking for. But this is a common approach.
Another way, which I would recommend, would be to not mix Ant compilation and Eclipse's compilation. Make the Ant script the way you describe (i. e. compile the main and test directories separately and create two separate jar files). Change the Eclipse compile directory to something different, for instance bin/eclipse. Use the Ant script when making official builds or building for release. Use Eclipse's building only for development/debugging. This way, your two build systems will not get in each other's way and confuse each other.
Hope this answers your question and I understood it correctly. Good luck!

Related

How do you tell sbt-eclipse to ignore (errors of) a very specific folder under /src

I have an infrastructure project that contains other projects as resources. (Because it compiles them on the fly). One of those contained projects is deliberately one that fails to compile.
This makes the entire project show in eclipse as "with errors".
How can I make sbt-eclipse configure eclipse such that e.g. anything under src/main/resources/foo should be ignored?
Of course this isn't exactly the scenario eclipse was built for, but might there be some clean way around it? as much as it matters, sbt itself does not try to compile these resources.
If not, maybe a way to tell eclipse to not even load source
directories under src/main/resources?
Thanks!

Eclipse: script compiler as part of a project

This question is not limited to lex and yacc, but how can I add a custom script compiler as part of a project? For example, I have the following files in the project:
grammar.y
grammar.l
test.script
The binary 'script_compiler' will be generated using grammar.y and grammar.l compiled by lex, yacc and g++. And then I want to use that generated script_compiler to compile test.script to generate CompiledScript.java. This file should be compiled along with the rest of the java files in the project. This setting is possible with XCode or make, but is it also possible with Eclipse alone? If not, how about together with Maven plugin?
(I might setup the script compiler as a separate project, but it would be nice if they can be put in the same project so that changes to the grammar files can be applied immediately)
Thanks in advance for your help!
You can add a custom "Builder" from the project properties dialog. This can be an ant script (with an optional target) or any other script or executable.
There are also maven plugins for ant and other scripting languages
If you just want to run an external program in Maven this is what you want: http://mojo.codehaus.org/exec-maven-plugin/ -- you can then run Maven targets from your IDE or command line and it should do the right thing either way.
To integrate with the normal compilation bind the plugin to the "generate-sources" phase and add the location where the Java files are generated to the "sourceRoot" option of the exec plugin. That way the compiler will pick them up.
Ideally you generate the code into a folder "target/generated-sources/MY_SCRIPT_NAME". That is the standard location for generated sources in the Maven world and e.g. IntelliJ IDEA will pick up source files inside of that location. Note that this doesn't work if the files are directly in "target/generated-sources".
The other option is to write your own Maven plugin, which is actually quite easy as well. See e.g. https://github.com/peterbecker/maven-code-generator

Writing an Eclipse-aware Ant task

I would like to write a simple Ant task that would interact with an Eclipse workspace to get some information from it. I would like to be able to use the various Eclipse API's (for example, IWorkspace).
My question is what would be the simplest way to go about doing this.
I have excellent knowledge of the Eclipse platform as a user of it - but none with development for Eclipse. I understand that, in runtime, my Ant task will have to be invoked under the same JRE as the workspace - that's a restriction I'm willing to be bound to.
I started by creating a Java project to hold my Ant task. I believe that the only thing in my way now is how to define the JAR dependency on Eclipse's JARs. I obviously don't want to depend on one specific Eclipse JAR as these are versioned (for example, Eclipse's "Resources" plugin). Is it possible to have my Java project buildtime-depend on "whatever the current JAR is for the Resources plugin"?
I think this article quite much addresses your problem: http://www.ibm.com/developerworks/rational/library/09/eclipsecustomanttasks/
It is targeted to the IBM Rational Application Developer, but that one is based on Eclipse and AFAIS there is not overly much non-eclipse-specific happening here, at least not regarding the specifics about how to make the task available in Eclipse (writing the plugin definition etc).
So, you want an Ant task that runs within Eclipse. And as you say, it's clear that those tasks are using the Eclipse API. As of this moment, I don't really understand how they're doing it. I've looked at the source of a couple of them and I still have questions.
To find the locations of all the Ant tasks contributed by Eclipse, do a Plug-in Search for org.eclipse.ant.core.antTasks. When I do that, I see twenty or so extensions, many of which define multiple tasks.
If you get the source bundle for a plugin that contributes one of these tasks, you can look at the source for it. RefreshLocalTask is in org.eclipse.core.resources; unfortunately, when I import this bundle into my workspace as a source project, the source for the Ant tasks doesn't get linked correctly. There is a separate jar (inside the bundle) for them, and, while the source is in the bundle, it's not clear how the jar is compiled. The upshot is that I don't have the Ant task source compiling in my workspace.
You can also Google for the Ant task source; here's the 3.6.0 source for RefreshLocalTask.
Anyway, in the source you can see calls to org.eclipse.core.resources.ResourcePlugin that are illustrative of what you probably need.
Ah, I see in the extension point description - right-click on one of those search results and choose "Show Description", or go there from the Manifest editor - that there is a flag you can set, "eclipseRuntime"; the text implies that if it is set, Eclipse will launch the task in the same VM.
You should probably say more about what you want to do, because there are several routes you can take.
Eclipse provides some Ant tasks that you can use in your build scripts. Here are a few. There are more, so search for "ant tasks" in the Eclipse docs; they're scattered throughout different pages. Eclipse Preferences (Window..Preferences, then select Ant/Runtime, and look at the "Contributed Entries" in the Classpath tab) shows you a list of Ant tasks that Eclipse contributes to the runtime whenever Ant is invoked from Eclipse; you can invoke any of these tasks yourself as long as you include the right jar.
It's possible to start up Eclipse from within an Ant task, because it's possible to start Eclipse from Java. You need to include the right jars and make the right calls; you also need to configure Eclipse correctly. "org.eclipse.core.runtime.adaptor.EclipseStarter" should give you some detail.
Perhaps you can use one or more of the variables Eclipse defines for use when launching Ant (or any other program). Try creating an External Tool Configuration (at the bottom of the Run menu) - select an Ant Build and try customizing it with arguments (from the Main tab) or environment variables (from the Environment) tab. Both give you access to Eclipse variables. But of course these are just values you can pass into your Ant script, not handles to anything you can invoke a method on.
What you can't do: I'm pretty sure that when Eclipse launches Ant, it is always in a separate VM, with no way to call back into Eclipse.
So perhaps you should say more about what you want to do.

How to compile & run a project-less file in Netbeans?

Netbeans, indeed any Java compiler and
executor, needs to know the classpath
to compile and run a file. When you
just open a file in Netbeans, you do
not tell it any of that information.
When you set up a project, that
process tells Netbeans where the Java
resources are.
Yet other IDEs can easily do this. It's not good practice, but it's simple and quick for "fooling around".
Is there any way to compile & run a file, that doesn't belong to a project, in Netbeans?
edit: The options are greyed out if the file doesn't belong to a project.
Your best option with NetBeans is just to create a dummy "try stuff" project that you know will never contain a shipping product but will allow you to experiment without having to create a new project every time.
You could even collect code snippets in different classes this way. If you add a main() method to each experimental class, you have a way to run them all in the IDE just by changing what you have set for the main project class. This is what I do and it works pretty well.
Why not using 'create new project with existing sources' which can be done for Java, Ruby, ... projects?
You can do so and netbeans will create only a nbproject folder within your project's dir and all should be fine.
This solution doesn't work great because projects are also "typed" and I work in 4 languages. I'd hate to have a "rubystuff" project, a "pythonstuff" project, "javastuff", etc, etc...

Managing dependencies with Eclipse and CVS

I have a bit of code for a dll that is needed by two or more projects in eclipse. Currently each project has a copy of the code and builds the DLL separately. I want to separate the dll code into a separate eclipse project so there is a common location. But I want to avoid the situation where we have to build the dll in the one project, then copy the dll back to the other projects and check the dll to each respective project. This will create a dll for each project that isn't traceable to the exact code that it was built with.
Is there a way to somehow symbolically link the dlls to another eclipse project that is using CVS as the version control system so that it is possible to tell which version of the code was used to create the dll? Am I making this too complicated or missing something obvious?
I thought about working sets in the package manager for eclipse, but I have to investigate more on how to use them with CVS to avoid making it a nightmare for the next person who checks it out and can't figure out why their project won't compile.
Thanks.
What about creating a new folder in a separate project. In the advanced section of creating a new folder there is an option to link to another location on the file system.
Or you could also create a container project that makes use of a projectset.psf file. Have the projectset file link to the different projects in your repository. When you want to check out that project, check out the container instead and right click on the projectset file and select Import Project Set...
If you are working with one workspace, you end up with three projects, each mirrored in CVS: One is the dll, the others are the projects using the dll (configured as a project dependency of these projects upon the dll project).
With three projects I wouldn't aim for working sets - they are good for managing a lot of projects within one workspace, for three projects, I'd consider them overkill. I usually tend to aim for several workspaces instead of working sets.
Regarding the next person working with these projects: You need to keep some kind of documentation about how to setup your projects. You might say that your eclipse project files do just that (as they define a project dependency upon another project) but this is for the machine - humans tend to like other communication means.
If you are worried about changes to the dll being incompatible to one project (because the person applying these changes doesn't care about the other project), aim for a build server. This will build all projects and dependent projects whenever something under version control changes, run all tests, provide a build number and package it all ready for use. This way you can be sure that - whatever is in your deliverable - can be reproduced, because the buildserver is not able to make local (uncommitted) changes to the code. Also a buildserver will signal failure (either broken API or broken tests) at the moment of the last commit (well - a few minutes later) and place the burden of repairing the damage on the one causing the damage.