/*
* JBoss, Home of Professional Open Source.
* Copyright 2007, Red Hat Middleware LLC, and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.classloader.spi.base;
import java.io.IOException;
import java.net.URL;
import java.util.Set;
import org.jboss.classloader.spi.ClassLoaderPolicy;
import org.jboss.classloader.spi.ClassLoaderPolicyFactory;
import org.jboss.classloader.spi.Loader;
import org.jboss.logging.Logger;
/**
* Base DelegateLoader.
*
* @author <a href="adrian@jboss.com">Adrian Brock</a>
* @version $Revision: 1.1 $
*/
public class BaseDelegateLoader implements Loader
{
/** The log */
private static final Logger log = Logger.getLogger(BaseDelegateLoader.class);
/** The delegate loader policy */
private volatile BaseClassLoaderPolicy delegate;
/** The policy factory */
private ClassLoaderPolicyFactory factory;
/**
* Create a new BaseDelegateLoader.
*
* @param delegate the delegate
* @throws IllegalArgumentException for a null delegate
*/
public BaseDelegateLoader(BaseClassLoaderPolicy delegate)
{
if (delegate == null)
throw new IllegalArgumentException("Null delegate");
this.delegate = delegate;
}
/**
* Create a new BaseDelegateLoader.
*
* @param factory the factory
* @throws IllegalArgumentException for a null factory
*/
public BaseDelegateLoader(ClassLoaderPolicyFactory factory)
{
if (factory == null)
throw new IllegalArgumentException("Null factory");
this.factory = factory;
}
BaseClassLoaderPolicy getPolicy()
{
BaseClassLoaderPolicy delegate = this.delegate;
if (delegate == null)
{
try
{
delegate = factory.createClassLoaderPolicy();
if (delegate == null)
{
log.trace("Factory did not create a delegate: " + factory);
}
else
{
ClassLoaderPolicy policy = (ClassLoaderPolicy) delegate;
initialise(policy);
this.delegate = delegate;
}
}
catch (Throwable t)
{
log.warn("Unexpected error creating policy from factory: " + factory, t);
}
}
return delegate;
}
/**
* Callback to initialise policy
*
* @param policy the policy
*/
protected void initialise(ClassLoaderPolicy policy)
{
// Nothing by default
}
BaseClassLoader getBaseClassLoader(String context)
{
BaseClassLoader result = null;
try
{
BaseClassLoaderPolicy policy = getPolicy();
if (policy != null)
result = policy.getClassLoader();
}
catch (IllegalStateException ignored)
{
}
if (result == null)
log.warn("Not " + context + " from policy that has no classLoader: " + toLongString());
return result;
}
public Class<?> loadClass(String className)
{
BaseClassLoader classLoader = getBaseClassLoader("loading class " + className);
if (classLoader != null)
return classLoader.loadClassLocally(className);
return null;
}
public URL getResource(String name)
{
BaseClassLoader classLoader = getBaseClassLoader("getting resource " + name);
if (classLoader != null)
return classLoader.getResourceLocally(name);
return null;
}
public void getResources(String name, Set<URL> urls) throws IOException
{
BaseClassLoader classLoader = getBaseClassLoader("getting resources " + name);
if (classLoader != null)
classLoader.getResourcesLocally(name, urls);
}
public Package getPackage(String name)
{
BaseClassLoader classLoader = getBaseClassLoader("getting package " + name);
if (classLoader != null)
return classLoader.getPackageLocally(name);
return null;
}
public void getPackages(Set<Package> packages)
{
BaseClassLoader classLoader;
try
{
classLoader = delegate.getClassLoader();
}
catch (IllegalStateException e)
{
log.warn("Not getting packages from policy that has no classLoader: " + toLongString());
return;
}
classLoader.getPackagesLocally(packages);
}
/**
* A long version of toString()
*
* @return the long string
*/
public String toLongString()
{
StringBuilder builder = new StringBuilder();
builder.append(getClass().getSimpleName());
builder.append("@").append(Integer.toHexString(System.identityHashCode(this)));
if (delegate != null)
builder.append("{delegate=").append(delegate.toLongString());
else
builder.append("{factory=").append(factory);
toLongString(builder);
builder.append('}');
return builder.toString();
}
/**
* For subclasses to add information for toLongString()
*
* @param builder the builder
*/
protected void toLongString(StringBuilder builder)
{
}
@Override
public String toString()
{
StringBuilder builder = new StringBuilder();
builder.append(getClass().getSimpleName());
builder.append("@").append(Integer.toHexString(System.identityHashCode(this)));
if (delegate != null)
builder.append("{delegate=").append(delegate);
else
builder.append("{factory=").append(factory);
builder.append('}');
return builder.toString();
}
}