org.jruby.embed.osgi.utils.OSGiBundleClassLoaderHelper Maven / Gradle / Ivy
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package org.jruby.embed.osgi.utils;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import org.osgi.framework.Bundle;
/**
* Various introspection tricks to access the file system from OSGi.
* Tested for felix and equinox.
*
* @author hmalphettes
*/
public class OSGiBundleClassLoaderHelper {
private static boolean identifiedOsgiImpl = false;
private static boolean isEquinox = false;
private static boolean isFelix = false;
private static void init(Bundle bundle)
{
identifiedOsgiImpl = true;
try
{
isEquinox = bundle.getClass().getClassLoader().loadClass("org.eclipse.osgi.framework.internal.core.BundleHost") != null;
}
catch (Throwable t)
{
isEquinox = false;
}
if (!isEquinox)
{
try
{
isFelix = bundle.getClass().getClassLoader().loadClass("org.apache.felix.framework.BundleImpl") != null;
}
catch (Throwable t2)
{
isFelix = false;
}
}
// System.err.println("isEquinox=" + isEquinox);
// System.err.println("isFelix=" + isFelix);
}
/**
* Assuming the bundle is started.
*
* @param bundle
* @return classloader object
*/
public static ClassLoader getBundleClassLoader(Bundle bundle)
{
String bundleActivator = (String)bundle.getHeaders().get("Bundle-Activator");
if (bundleActivator == null)
{
bundleActivator = (String)bundle.getHeaders().get("Jetty-ClassInBundle");
}
if (bundleActivator != null)
{
try
{
return bundle.loadClass(bundleActivator).getClassLoader();
}
catch (ClassNotFoundException e)
{
// should not happen as we are called if the bundle is started
// anyways.
e.printStackTrace();
}
}
// resort to introspection
if (!identifiedOsgiImpl)
{
init(bundle);
}
if (isEquinox)
{
return internalGetEquinoxBundleClassLoader(bundle);
}
else if (isFelix)
{
return internalGetFelixBundleClassLoader(bundle);
}
return null;
}
private static Method Equinox_BundleHost_getBundleLoader_method;
private static Method Equinox_BundleLoader_createClassLoader_method;
private static ClassLoader internalGetEquinoxBundleClassLoader(Bundle bundle)
{
// assume equinox:
try
{
if (Equinox_BundleHost_getBundleLoader_method == null)
{
Equinox_BundleHost_getBundleLoader_method = bundle.getClass().getClassLoader().loadClass("org.eclipse.osgi.framework.internal.core.BundleHost")
.getDeclaredMethod("getBundleLoader",new Class[] {});
Equinox_BundleHost_getBundleLoader_method.setAccessible(true);
}
Object bundleLoader = Equinox_BundleHost_getBundleLoader_method.invoke(bundle,new Object[] {});
if (Equinox_BundleLoader_createClassLoader_method == null && bundleLoader != null)
{
Equinox_BundleLoader_createClassLoader_method = bundleLoader.getClass().getClassLoader().loadClass(
"org.eclipse.osgi.internal.loader.BundleLoader").getDeclaredMethod("createClassLoader",new Class[] {});
Equinox_BundleLoader_createClassLoader_method.setAccessible(true);
}
return (ClassLoader)Equinox_BundleLoader_createClassLoader_method.invoke(bundleLoader,new Object[] {});
}
catch (Throwable t)
{
t.printStackTrace();
}
return null;
}
private static Field Felix_BundleImpl_m_modules_field;
private static Field Felix_ModuleImpl_m_classLoader_field;
private static ClassLoader internalGetFelixBundleClassLoader(Bundle bundle)
{
// assume felix:
try
{
// now get the current module from the bundle.
// and return the private field m_classLoader of ModuleImpl
if (Felix_BundleImpl_m_modules_field == null)
{
Felix_BundleImpl_m_modules_field = bundle.getClass().getClassLoader().loadClass("org.apache.felix.framework.BundleImpl").getDeclaredField(
"m_modules");
Felix_BundleImpl_m_modules_field.setAccessible(true);
}
Object[] moduleArray = (Object[])Felix_BundleImpl_m_modules_field.get(bundle);
Object currentModuleImpl = moduleArray[moduleArray.length - 1];
if (Felix_ModuleImpl_m_classLoader_field == null && currentModuleImpl != null)
{
Felix_ModuleImpl_m_classLoader_field = bundle.getClass().getClassLoader().loadClass("org.apache.felix.framework.ModuleImpl").getDeclaredField(
"m_classLoader");
Felix_ModuleImpl_m_classLoader_field.setAccessible(true);
}
// first make sure that the classloader is ready:
// the m_classLoader field must be initialized by the
// ModuleImpl.getClassLoader() private method.
ClassLoader cl = (ClassLoader)Felix_ModuleImpl_m_classLoader_field.get(currentModuleImpl);
if (cl == null)
{
// looks like it was not ready:
// the m_classLoader field must be initialized by the
// ModuleImpl.getClassLoader() private method.
// this call will do that.
bundle.loadClass("java.lang.Object");
cl = (ClassLoader)Felix_ModuleImpl_m_classLoader_field.get(currentModuleImpl);
// System.err.println("Got the bundle class loader of felix_: "
// + cl);
return cl;
}
else
{
// System.err.println("Got the bundle class loader of felix: " +
// cl);
return cl;
}
}
catch (Throwable t)
{
t.printStackTrace();
}
return null;
}
}