/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.jci;
import java.io.InputStream;
import java.net.URL;
import org.apache.commons.jci.listeners.ReloadNotificationListener;
import org.apache.commons.jci.stores.ResourceStore;
import org.apache.commons.jci.stores.ResourceStoreClassLoader;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* The ReloadingClassLoader uses a delegation mechansim to allow
* classes to be reloaded. That means that loadClass calls may
* return different results if the class was changed in the underlying
* ResourceStore.
*
* @author tcurdt
*/
public class ReloadingClassLoader extends ClassLoader implements ReloadNotificationListener {
private final Log log = LogFactory.getLog(ReloadingClassLoader.class);
private final ClassLoader parent;
private ResourceStore[] stores = new ResourceStore[0];
private ClassLoader delegate;
public ReloadingClassLoader( final ClassLoader pParent ) {
super(pParent);
parent = pParent;
delegate = new ResourceStoreClassLoader(parent, stores);
}
public boolean addResourceStore( final ResourceStore pStore ) {
try {
final int n = stores.length;
final ResourceStore[] newStores = new ResourceStore[n + 1];
System.arraycopy(stores, 0, newStores, 1, n);
newStores[0] = pStore;
stores = newStores;
delegate = new ResourceStoreClassLoader(parent, stores);
return true;
} catch ( final RuntimeException e ) {
log.error("could not add resource store " + pStore);
}
return false;
}
public boolean removeResourceStore( final ResourceStore pStore ) {
final int n = stores.length;
int i = 0;
// FIXME: this should be improved with a Map
// find the pStore and index position with var i
while ( ( i < n ) && ( stores[i] != pStore ) ) {
i++;
}
// pStore was not found
if ( i == n ) {
return false;
}
// if stores length > 1 then array copy old values, else create new empty store
final ResourceStore[] newStores = new ResourceStore[n - 1];
if (i > 0) {
System.arraycopy(stores, 0, newStores, 0, i);
}
if (i < n - 1) {
System.arraycopy(stores, i + 1, newStores, i, (n - i - 1));
}
stores = newStores;
delegate = new ResourceStoreClassLoader(parent, stores);
return true;
}
public void handleNotification() {
log.debug("reloading");
delegate = new ResourceStoreClassLoader(parent, stores);
}
@Override
public void clearAssertionStatus() {
delegate.clearAssertionStatus();
}
@Override
public URL getResource(String name) {
return delegate.getResource(name);
}
@Override
public InputStream getResourceAsStream(String name) {
return delegate.getResourceAsStream(name);
}
@Override
public Class<?> loadClass(String name) throws ClassNotFoundException {
return delegate.loadClass(name);
}
@Override
public void setClassAssertionStatus(String className, boolean enabled) {
delegate.setClassAssertionStatus(className, enabled);
}
@Override
public void setDefaultAssertionStatus(boolean enabled) {
delegate.setDefaultAssertionStatus(enabled);
}
@Override
public void setPackageAssertionStatus(String packageName, boolean enabled) {
delegate.setPackageAssertionStatus(packageName, enabled);
}
}