inverse_loading in WASCE 3.0.0.3 / Geronimo 3.0 - apache

I am trying to deploy a war onto a IBM Websphere Application Server Community Edition (WASCE) 3.0.0.3. I had some jars conflicting problems between those jars that comes with WASCE 3.0.0.3 and the jars comes from our application dependencies. At the end, I fixed the problem by using below property in geronimo-web.xml to force WASCE to load jars from my application.
<import-package>!the.conflicting.jars</import-package>
However, I would like to force WASCE to always take jars from my application first, i.e. inverse the default classloader behavior to load from application first. What is the correct config to change in this case?
After some searches, WASCE 3.0 is based on Geronimo 3.0 according to link. I found setting <inverse-classloading> in geronimo-web.xml may be helpful. But below two documents on Apache Geronimo 3.0 website mention that this function is no longer available on Geronimo 3.0
in Migrating from G 2.x to G 3.x, it says:
inverse-classloading Geronimo 3.0 does not support the element in the deployment plan.
in geronimo-web.xml,
The <sys:environment> element contains the following elements:
...
The <inverse-classloading> element can be used to specify that standard classloader delegation is to be reversed for this module. The Geronimo classloader delegation follows the Java EE 5 specifications, and the normal behavior is to load classes from a parent classloader (if available) before checking the current classloader. ...... ...... (Not supported in 3.0, use <import-package/> instead)
So if <inverse-classloading> is no longer available, what is the equivalent of this property in WASCE 3.0.0.3? Or how exactly should I do this using <import-package/> for all duplicated jars?

In the link you mentioned you will find the following section
<sys:environment>
The <sys:environment> XML element uses the Geronimo System namespace, which is used to specify the common elements for common libraries and module-scoped services, and is documented here:
http://geronimo.apache.org/schemas-3.0/docs/geronimo-module-1.2.xsd.html
The element contains the following elements:
The <moduleId> element is used to provide the configuration name for the web application as deployed in the Geronimo server. It contains elements for the groupId, artifactId, version and module type. Module IDs are normally printed with slashes between the four components, such as GroupID/ArtifactID/Version/Type.
The <dependencies> element is used to provide the configurations and third party libraries on which the web module is dependent upon. These configurations and libraries are made available to the web module via the Geronimo classloader hierarchy.
The <bundle-activator> element is used to create Bundle-Activator header in the manifest file of the web application. It specifies the entry point of the web application as deployed in the Geronimo server.
The <bundle-classPath> element is used to create Import-Package header in the manifest file of the web application. It contains a list of directories or embedded jar files, which are also called bundle resources and extend the classpath of the web application.
The <import-package> element is used to create Import-Package header in the manifest file of the web application. It specifies a list of packages to be resolved before the web application is started. Use <import-package>!packagename</import-package> to override the specific package in server.
The <export-package> element is used to create Export-Package header in the manifest file of the web application. It specifies a list of packages to be exported.
The <require-bundle> element is used create Require-Bundle header in the manifest file of the web application. It specifies a list of bundles to bind to regardless their packages.
The <dynamic-import-package> element is used to create DynamicImport-Package header in the manifest file of the web application. It specifies a list of packaged to be imported dynamically, especially during class loading.
So basically, you need to add the following directive i.e
<sys:import-package>!package-class-name-here*</sys:import-package> within the <sys:environment> stanza. Typically before the Application Context-Root directive.
As you already know, this is in the geronimo-web.xml embedded in the Application WAR/EAR -- as mentioned in the link
http://geronimo.apache.org/GMOxDOC30/geronimo-webxml.html

Related

seedstack, how to read the base url from properties file

I am using feign client for doing rest call.I kept my base url in application .yaml file.
But I want application.yaml should read the base url from properties file kept in external location.
I am facing this issue when I am trying to do the deployment of my web application.
SeedStack configuration files can contain placeholders (or macros as we call them). Some runtime information is available under the runtime configuration node and can be referenced using macros.
This is the case for the base URL if you run your Web application with the embedded Web server. You can refer to it from your properties files regardless of their location:
someProperty=${runtime.web.baseUrl}/something
Warning: in SeedStack versions older than 18.11, the base URL is available under web.runtime.baseUrl instead. This has been changed in the latest version to regroup all runtime information in the same place. Note that it also had a trailing slash back then.
Relevant docs:
Macros: http://seedstack.org/docs/core/configuration/#macros
Web runtime info: http://seedstack.org/docs/web/#runtime-information
Release notes about the change: http://seedstack.org/posts/18.11-release-notes/#runtime-information-update

How to add org.eclipse.swt (and other plugin dependencies) as an automatic Java9 module?

In order to be able to use my Eclipse plugin "treezCore" also as a Java9 module I created a module-info.java in my src folder.
Furthermore, I moved the Plug-in Dependencies from the Classpath to the Modulepath. I can see a module "org.eclipse.swt.3.106.1.v20170926" in the plugin dependencies:
However, I am not able to reference that module in my module-info.java. I tried
require org.eclipse.swt.3.106.1.v20170926;
require org.eclipse.swt;
require swt;
None of those options worked. The jar file \plugins\org.eclipse.swt_3.106.1.v20170926-0519.jar that is used by Eclipse does not contain a module definition and
jar --file org.eclipse.swt_3.106.1.v20170926-0519.jar -d
says that the module descriptor can not be derived. Also see
Unable to derive module descriptor for auto generated module names in Java 9?
If I download a newer version of swt.jar from
http://download.eclipse.org/eclipse/downloads/drops4/R-4.7.1a-201710090410/download.php?dropFile=swt-4.7.1a-win32-win32-x86_64.zip
I get following output that looks promising:
swt automatic
requires java.base mandated
contains org.eclipse.swt
contains org.eclipse.swt.accessibility
contains org.eclipse.swt.awt
contains org.eclipse.swt.browser
contains org.eclipse.swt.custom
contains org.eclipse.swt.dnd
contains org.eclipse.swt.events
contains org.eclipse.swt.graphics
contains org.eclipse.swt.internal
contains org.eclipse.swt.internal.gdip
contains org.eclipse.swt.internal.image
contains org.eclipse.swt.internal.mozilla
contains org.eclipse.swt.internal.mozilla.init
contains org.eclipse.swt.internal.ole.win32
contains org.eclipse.swt.internal.opengl.win32
contains org.eclipse.swt.internal.webkit
contains org.eclipse.swt.internal.win32
contains org.eclipse.swt.layout
contains org.eclipse.swt.ole.win32
contains org.eclipse.swt.opengl
contains org.eclipse.swt.printing
contains org.eclipse.swt.program
contains org.eclipse.swt.widgets
I also depend on org.eclipse.jface and could not find a seperate download for it.
=> Do I really have to wait for a new release of Eclipse that uses new plugin versions including module definitions?
Or can I somehow reference the old version of swt from the plugins folder, even if it does not include a module definition? I looked for an easy way to define an alias or a fallback dependency e.g.
requires ../plugins/org.eclipse.swt_3.106.1.v20170926-0519.jar as 'org.eclipse.swt'
or
requires org.eclipse.swt fallback ../plugins/org.eclipse.swt_3.106.1.v20170926-0519.jar
but module-info.java does not seem to support such a syntax.
I have about 20 plugin dependencies and do not want to manually download each of them (if it would be possible) and include them as external jar file. Nor do I want to hack the individual Manifest/jar files in the Eclipse plugin folder. There are many jar files I would need to alter and an update of Eclipse would break that hack.
I am using Eclipse for RCP and RAP Developers, Version: Oxygen.1a Release (4.7.1a), Build id: 20171005-1200
Edit
When using Version: Photon Milestone 4 (4.8.0M4) Build id: 20171214-1849, the error in module-info.java vanishes when using
require org.eclipse.swt;
and having the Plug-in Dependencies in the Modulepath.
However, my imports do not work yet, see following image. If I move the Plug-in Dependencies from the Modulepath to the Classpath, the imports work but the error in module-info.java reappears.
I created a min example at
https://github.com/stefaneidelloth/Java9EclipsePluginExample/tree/master/MyPlugin
and I filed a bug report at
https://bugs.eclipse.org/bugs/show_bug.cgi?id=529089
Related questions:
How to use 3rd party library in Java9 module?
Unable to derive module descriptor for auto generated module names in Java 9?
Force Eclipse (Helios) to use a newer version of SWT at application runtime
JFace libraries stand-alone download (not picked from Eclipse plug-ins)
New Keywords in Java 9
What you observe is tracked in bug 525660, which starts with the observation that all existing (OSGi) artifacts of Eclipse don't work as automatic modules, because Java 9 fails to derive a valid module name from jar filenames of the shape org.eclipse.swt_3.106.1.v20170926-0519.jar.
Since this was discovered too late to request improving the algorithm for automatic module name derivation, this can only be fixed by adding Automatic-Module-Name headers to the manifests of future releases.
This header is present starting from Photon M4 as can be seen in org.eclipse.swt_3.107.0.v20171205-0742.jar, containing:
Automatic-Module-Name: org.eclipse.swt

How to make a resource file visible to all bundles in OSGi?

I'd like to include a resource file (e.g. some xml config file) in my bundle and make it visible to all other bundles in the container. Is it possible without using the Fragment-Host manifest header? I'd like this resource file to always be visible in the classpath of all bundles running alongside my bundle, even those that do not exist yet, but will potentially be added in future.
EDIT:
To clarify - that resource must be available passively, i.e. the other bundles should be able to find it in their classpath, and not by refering to any special API or service of my bundle.
Some more background - my environment is a bit messy but I have no control over it and cannot change its existing bundles. The only way I can modify it is by adding my own bundles. That environment includes several copies of the ch.qos.logback.classic bundle. When logback starts up, it looks for specific XML config files in the classpath. If it doesn't find any of them, then its default behaviour is to print everything to stdout with debug level. This environment was previously used to host a GUI application so it didn't matter that much before, but now I am trying to adapt it so I can use some of its functionality in headless mode. So now it becomes important to me to be able to configure it in such a way that only warning and errors are printed to the console.
In general, no you cannot do this. Class-space isolation is at the heart of OSGi, but you want to put a resource in the class loader of one bundle and make it visible to all other bundles. That's not OSGi, it's the global application classpath.
The only thing you can do to add to the internal classpath of a specific bundle is to write a fragment which attaches to that bundle. A fragment can attach to multiple host bundles, but only if those hosts have the same symbolic name, i.e. because they are different versions of the same bundle. See OSGi R6 Core Specification, section 3.14.
You did however state that the bundles you want to attach are all copies of ch.qos.logback.classic. If that means they all have that exact symbolic name then perhaps a fragment will work after all.
You can not change the classpath of other bundles this way.
What you can do is retrieve the classloader of your bundle from your bundleContext. You can give this classloader to another bundle to retrieve your resource.
ClassLoader cl = context.getBundle().adapt(BundleWiring.class).getClassLoader();
Another option is to give the other bundle the URL of the resource.
As long as the resource is on the classpath, any bundle can access the resource if it can get hold of the class loader of the bundle that contains the resource.
For example:
ClassLoader classLoaderOfBundleWithResource = ...
classLoaderOfBundleWithResource.getResourceAsStream("org/example/resource.xml");
From a maintenance and API point of view, I would not recommend exposing a resource that way. Java types are much better suited therefore. Instead, let the resource bundle export a class that gives clients access to the contents of the resource.
For example:
public class XmlDocumentProvider {
public InputStream openDocument() {
return getClass().getResourceAsStream("resource.xml");
}
}
Assuming that both the resource.xml and the XmlDocumentProvider reside in the same package, openDocument will return the resource content just like in the first example.

Can Struts 1.x Resource Bundles be placed elsewhere than the classes directory?

This is for Struts 1.x (I'm using 1.3.10).
I've noticed that Struts is unable to pick up resource bundles in the ApplicationResources.properties file if it is not placed somewhere in the default classpath (e.g., com.abc.SomePackage).
For instance, if I put the ApplicationResources.properties file in a custom folder /WEB-INF/strutsResources and configure the struts-config.xml thus:
<message-resources parameter="/WEB-INF/strutsResources/ApplicationResources"/>
I've read that the resources need to be on the classpath so I've also tried adding the /WEB-INF/strutsResources folder to the classpath. It still does not pick up the resource keys.
I've double-checked that the strutsResources folder is actually deployed to the server (I'm using Glassfish v3), so the file is there, it's just not being parsed.
P.S.
If you're wondering why I'm trying to do this, I just wanted to organize my code a little better ("better," IMO). Since the ApplicationResources.properties file is not really a class, I wanted to place it in a resources folder by itself.
I've checked that placing the ApplicationResources file in a package in the src directory works just fine.
Ultimately, the answer is yes. You can play some interesting games by configuring a custom className and/or factory and get messages however you want (including from a database) and so on. This allows you to customize whatever you want*.
I agree the resources aren't a class, but putting them on the classpath is a common practice, and allows resources to be loaded as a resource, e.g., from inside a jar. I'm sympathetic, but I'd leave it as-is.
*Like reversing all the text; a fun prank to play on your co-workers and QA department.
Its best leave it on the classpath.
It's stadard practise to include properties files on the classpath, especially if you're planning on packaging it up in your WAR/EAR. You're keeping it under WEB-INF so you gain no benefit from moving it off the classpath, and you'll just confuse other developers who have to work on the project and you've had to put a hack in to make this work.
If you want to keep your files external to your deployable WAR/EAR then that's a valid reason for not using the classpath. Typically this will require some configuration as part of your deployment to specify where the file is to reside.
For example specify the location using
a JVM argument (e.g. -Dprops.file=/config/myapp.properites)
lookup from a JNDI resource
use a PropertiesFactoryBean if you're using the Spring framework (I
use Spring's ApplicationContext with Struts 1 MVC)
read properties from a database writing your own
ApplicationPropertiesDAO class that initialises itself durnig your
applications bootstrap process (e.g. Spring application contact,
Servlet in web.xml, Listener in web.xml, etc)

How do I avoid having to manually tweak Import-Package headers with Maven bundle-plugin?

I'm happily using the Maven bundle-plugin to create OSGi manifest headers for my modules. However, when there are configuration files that pull in classes which aren't referenced directly in the code, the plugin can't tell which packages it's going to need.
One example is a bundle with domain models that constitute a Persistence Unit for JPA. The driver class is part of the PU configuration and either set in an XML file or at runtime when the EntityManager is instantiated. I have to manually add an Import-Package header for the driver class that I want to load, or I get CNF errors.
Another example is a Struts war, where the web.xml pulls in the Struts dispatcher that's otherwise not found anywhere in the code and has to be manually added to the headers.
How can I avoid this?
I tried adding the required packages as dependencies with a provided scope, but that didn't help.
In the plug-in section of the bnd configuration you can specify plug-ins to analyze these files and contribute to the import-package header. For spring it looks like this:
<_plugin>aQute.lib.spring.SpringComponent</_plugin>
I am not sure, what descriptors are supported on top of spring. Just take a look at the source (it's in the Apache Felix SVN) and see for yourself. In the worst case you have to write your own plug-in, but at least it is possible! Also peter kriens site about the bnd explains the usage and some internals.
Other then that I am not aware of any simple solution.