Accessing the resources during active annotation processing.

[chris...@gmail.com]

I am revisiting some work I did on accessing resource bundles (i.e. properties files) during active annotation processing.

I just can't figure out how to do it! Can it be done?

I have an eclipse project structure like this:

myProject

--- source

------ myPackage

--------- myAnnotatedClass.xtend

--- resouces

------ myPackage

--------- myBundle.properties

I want to be able to load the myBundle.properties file?

Here is what I have tried:

Method 1:

ResourceBundle.getBundle("myBundle") 

ResourceBundle.getBundle("myPackage.myBundle")

Both don't yield anything.

Method 2:

Getting the project folder (using FileSystemSupport) for the annotated class, works it gives me: /myProject

But when I try to get the children of it, I get nothing.

Ideas

Could the various context objects available during annotation parsing be enhanced to find/lookup/load a resource in the current project/classpath just as you can with a ClassLoader? 

Could the FileSystemSupport be enhanced to support the entire project structure, or find/lookup/load a resource ?

Can anyone shed some light on the situation?

Thanks

C.

[Sven Efftinge]

On Dec 6, 2013, at 3:44 PM, chris...@gmail.com wrote:

Ideas

Could the FileSystemSupport be enhanced to support the entire project structure, or find/lookup/load a resource ?

That's how it is intended to work.

Can you share what exactly you tried?

Thanks,

Sven

[chris...@gmail.com]

Sven, here is some more information, and a simplification of what I was trying to do:

My Annotation

@Retention(RetentionPolicy::SOURCE)

@Target(ElementType::TYPE)

@Active(ProjectStructureProcessor)

annotation ProjectStructure

{ 

}

My Annotated Interface

@ProjectStructure()

interface ResourceDefinition

{

def String aaa() 

}

My Annotation Processor

class ProjectStructureProcessor extends AbstractInterfaceProcessor

{ 

def private List<Path> getPaths(Path folder, extension TransformationContext context)

{

log("folder: " + folder)

val list = <Path>newArrayList()

val q = new LinkedList<Path>

q.offer(folder) 

while (!q.empty)

{

val p = q.poll

log("poll q: " + p) 

list.add(p) 

context.getChildren(p).forEach[q.add(it)]

}

list

}

override doRegisterGlobals(InterfaceDeclaration annotatedInterface, RegisterGlobalsContext context)

{

super.doRegisterGlobals(annotatedInterface, context)

}

override doTransform(MutableInterfaceDeclaration annotatedInterface, extension TransformationContext context)

{

super.doTransform(annotatedInterface, context)

log(annotatedInterface.toString) 

val projectFolder = annotatedInterface.compilationUnit.filePath.projectFolder

log("project\n" + getPaths(projectFolder, context).toString) 

val sourceFolder = annotatedInterface.compilationUnit.filePath.sourceFolder

log("source\n" + getPaths(sourceFolder, context).toString) 

val targetFolder = annotatedInterface.compilationUnit.filePath.targetFolder

log("target\n" + getPaths(targetFolder, context).toString)

}

override doGenerateCode(InterfaceDeclaration annotatedInterface, extension CodeGenerationContext context)

{

super.doGenerateCode(annotatedInterface, context)

} 

}

And here is an exception I get on the annotated interface:

Error during annotation processing:

java.lang.IllegalArgumentException:

   Path must include project and resource name: /MiscTools

at

   org.eclipse.core.runtime.Assert.isLegal(Assert.java:63)

at

   org.eclipse.core.internal.resources.Workspace.newResource(Workspace.java:2163)

at

   org.eclipse.core.internal.resources.Container.getFolder(Container.java:222)

at

   org.eclipse.xtext.xbase.ui.file.EclipseFileSystemSupportImpl.getEclipseFolder(EclipseFileSystemSupportImpl.java:56)

at

   org.eclipse.xtext.xbase.ui.file.EclipseFileSystemSupportImpl.getChildren(EclipseFileSystemSupportImpl.java:76)

at

   org.eclipse.xtend.core.macro.TransformationContextImpl.getChildren(TransformationContextImpl.java:338)

at

   resources.ProjectStructureProcessor.getPaths(ProjectStructureProcessor.java:42)

at

   resources.ProjectStructureProcessor.doTransform(ProjectStructureProcessor.java:70)

at

   annotation.processing.AbstractInterfaceProcessor.doTransform(AbstractInterfaceProcessor.java:18)

If I try and process the source directory first (rather than the project folder) I get a different exception on the annotated interface:

Error during annotation processing:

org.eclipse.core.internal.resources.ResourceException:

   Resource '/MiscTools/source/tools/SomeTool.xtend'

   does not exist.

at org.eclipse.core.internal.resources.Resource.checkExists(Resource.java:341)

at

   org.eclipse.core.internal.resources.Resource.checkAccessible(Resource.java:215)

at

   org.eclipse.core.internal.resources.Container.members(Container.java:266)

at

   org.eclipse.core.internal.resources.Container.members(Container.java:249)

at

   org.eclipse.xtext.xbase.ui.file.EclipseFileSystemSupportImpl.getChildren(EclipseFileSystemSupportImpl.java:77)

at

   org.eclipse.xtend.core.macro.TransformationContextImpl.getChildren(TransformationContextImpl.java:338)

...

I hope this sheds some light on the problem.

Thanks,

Chris.

[Anton Kosyakov]

Hi,

It seems there is a bug into implementation of org.eclipse.xtext.xbase.ui.file.EclipseFileSystemSupportImpl.getChildren method for a project path.

You can introduce annotation property to narrow search path and avoid this problem, e.g. /MiscTools/resources will be a search path instead of just /MiscTools. 

I’ve done an example for you:

1. Client: 

package foo

@Foo('resources’) // this annotation will iterate over all sub folders of ‘resources' folder and collect properties files

class FooClient {

}

2. Annotation:

package foo

import java.util.List

import org.eclipse.xtend.lib.macro.AbstractClassProcessor

import org.eclipse.xtend.lib.macro.Active

import org.eclipse.xtend.lib.macro.TransformationContext

import org.eclipse.xtend.lib.macro.declaration.MutableClassDeclaration

import org.eclipse.xtend.lib.macro.file.Path

@Active(FooProcessor)

annotation Foo {

String value // a folder path for processing

}

class FooProcessor extends AbstractClassProcessor {

override doTransform(MutableClassDeclaration annotatedClass, extension TransformationContext context) {

val projectFolder = annotatedClass.compilationUnit.filePath.projectFolder

val value = annotatedClass.findAnnotation(Foo.newTypeReference.type).getValue('value') as String

val path = projectFolder.append(value)

val properties = path.findProperties(newArrayList, context)

...

}

def List<Path> findProperties(Path path, List<Path> results, extension TransformationContext context) {

for (child : path.children) {

if (child.folder) {

child.findProperties(results, context)

}

if (child.file && child.fileExtension.equals("properties")) {

results += child

}

}

results

}

}

Might it even be enough to specify a path to the particular file and avoid iterating over subfolders at all?

Best regards,

Anton

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[chris...@gmail.com]

Thanks for you reply Anton, I tried you suggestion and it works - thank you.

I hope the bug in org.eclipse.xtext.xbase.ui.file.EclipseFileSystemSupportImpl.getChildren is fixed soon, as I didn't want to have project configuration polluting the annotation/code, but it's a work around for now.

Chris

[Anton Kosyakov]

Hi,

https://bugs.eclipse.org/bugs/show_bug.cgi?id=423661 - the bug for it

Regarding to the second exception: 

org.eclipse.core.internal.resources.ResourceException:

   Resource '/MiscTools/source/tools/SomeTool.xtend'

   does not exist.

at org.eclipse.core.internal.resources.Resource.checkExists(Resource.java:341)

at

   org.eclipse.core.internal.resources.Resource.checkAccessible(Resource.java:215)

at

   org.eclipse.core.internal.resources.Container.members(Container.java:266)

at

   org.eclipse.core.internal.resources.Container.members(Container.java:249)

at

   org.eclipse.xtext.xbase.ui.file.EclipseFileSystemSupportImpl.getChildren(EclipseFileSystemSupportImpl.java:77)

at

   org.eclipse.xtend.core.macro.TransformationContextImpl.getChildren(TransformationContextImpl.java:338)

You tried to get children (subfolders) of the file, it’s just not possible. You have to check first whether a given child is folder.

Best regards,

Anton