BusFactory.java
/**
* 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.cxf;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.util.Iterator;
import java.util.Map;
import java.util.WeakHashMap;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.apache.cxf.common.classloader.ClassLoaderUtils;
import org.apache.cxf.common.logging.LogUtils;
import org.apache.cxf.common.util.SystemPropertyAction;
/**
* Factory to create CXF Bus objects.
* <p>CXF includes a large number of components that provide services, such
* as WSDL parsing, and message processing. To avoid creating these objects over and over, and to
* allow them to be shared easily, they are associated with a data structure called a bus.
* </p>
* <p>
* You don't ever have to explicitly create or manipulate bus objects. If you simply use the CXF
* or JAX-WS APIs to create clients or servers, CXF will create a default bus for you. You can create a bus
* explicitly if you need to customize components on the bus or maintain several independent buses
* with independent configurations.
* </p>
* <p>
* This class maintains the default bus for the entire process and a set of thread-default buses. All CXF
* components that reference the bus, which is to say all CXF components, will obtain a default bus from this
* class if you do not set a specific bus.
* </p>
* <p>
* If you create a bus when there is no default bus in effect, that bus will become the default bus.
* </p>
* <p>
* This class holds a reference to the global default bus and a reference to each thread default
* bus. The thread references are weak with respect to the threads, but otherwise ordinary.
* Thus, so long as the thread remains alive
* there will be a strong reference to the bus, and it will not get garbage-collected.
* If you want to recover memory used CXF, you can set
* the default and per-thread default bus to null, explicitly.
* </p>
*/
public abstract class BusFactory {
public static final String BUS_FACTORY_PROPERTY_NAME = "org.apache.cxf.bus.factory";
public static final String DEFAULT_BUS_FACTORY = "org.apache.cxf.bus.CXFBusFactory";
protected static Bus defaultBus;
static class BusHolder {
Bus bus;
volatile boolean stale;
}
protected static final Map<Thread, BusHolder> THREAD_BUSSES = new WeakHashMap<>();
protected static final ThreadLocal<BusHolder> THREAD_BUS = new ThreadLocal<>();
private static final Logger LOG = LogUtils.getL7dLogger(BusFactory.class);
/**
* Creates a new bus. While concrete <code>BusFactory</code> may offer differently parameterized methods
* for creating a bus, all factories support this no-arg factory method.
*
* @return the newly created bus.
*/
public abstract Bus createBus();
/**
* Returns the default bus, creating it if necessary.
*
* @return the default bus.
*/
public static synchronized Bus getDefaultBus() {
return getDefaultBus(true);
}
/**
* Returns the default bus
*
* @param createIfNeeded Set to true to create a default bus if one doesn't exist
* @return the default bus.
*/
public static synchronized Bus getDefaultBus(boolean createIfNeeded) {
if (defaultBus == null && createIfNeeded) {
defaultBus = newInstance().createBus();
}
if (defaultBus == null) {
// never set up.
return null;
}
return defaultBus;
}
private static BusHolder getThreadBusHolder(boolean set) {
BusHolder h = THREAD_BUS.get();
if (h == null || h.stale) {
Thread cur = Thread.currentThread();
synchronized (THREAD_BUSSES) {
h = THREAD_BUSSES.get(cur);
}
if (h == null || h.stale) {
h = new BusHolder();
synchronized (THREAD_BUSSES) {
THREAD_BUSSES.put(cur, h);
}
}
if (set) {
THREAD_BUS.set(h);
}
}
return h;
}
/**
* Sets the default bus.
*
* @param bus the default bus.
*/
public static synchronized void setDefaultBus(Bus bus) {
defaultBus = bus;
BusHolder b = getThreadBusHolder(false);
b.bus = bus;
if (bus == null) {
b.stale = true;
THREAD_BUS.remove();
}
}
/**
* Sets the default bus for the thread.
*
* @param bus the default bus.
*/
public static void setThreadDefaultBus(Bus bus) {
if (bus == null) {
BusHolder h = THREAD_BUS.get();
if (h == null) {
Thread cur = Thread.currentThread();
synchronized (THREAD_BUSSES) {
h = THREAD_BUSSES.get(cur);
}
}
if (h != null) {
h.bus = null;
h.stale = true;
THREAD_BUS.remove();
}
} else {
BusHolder b = getThreadBusHolder(true);
b.bus = bus;
}
}
/**
* Sets the default bus for the thread.
*
* @param bus the new thread default bus.
* @return the old thread default bus or null
*/
public static Bus getAndSetThreadDefaultBus(Bus bus) {
if (bus == null) {
BusHolder b = THREAD_BUS.get();
if (b == null) {
Thread cur = Thread.currentThread();
synchronized (THREAD_BUSSES) {
b = THREAD_BUSSES.get(cur);
}
}
if (b != null) {
Bus orig = b.bus;
b.bus = null;
b.stale = true;
THREAD_BUS.remove();
return orig;
}
return null;
}
BusHolder b = getThreadBusHolder(true);
Bus old = b.bus;
b.bus = bus;
return old;
}
/**
* Gets the default bus for the thread.
*
* @return the default bus.
*/
public static Bus getThreadDefaultBus() {
return getThreadDefaultBus(true);
}
/**
* Gets the default bus for the thread, creating if needed
*
* @param createIfNeeded Set to true to create a default bus if one doesn't exist
* @return the default bus.
*/
public static Bus getThreadDefaultBus(boolean createIfNeeded) {
if (createIfNeeded) {
BusHolder b = getThreadBusHolder(false);
if (b.bus == null) {
b.bus = createThreadBus();
}
return b.bus;
}
BusHolder h = THREAD_BUS.get();
if (h == null || h.stale) {
Thread cur = Thread.currentThread();
synchronized (THREAD_BUSSES) {
h = THREAD_BUSSES.get(cur);
}
}
return h == null || h.stale ? null : h.bus;
}
private static synchronized Bus createThreadBus() {
BusHolder b = getThreadBusHolder(false);
if (b.bus == null) {
b.bus = getDefaultBus(true);
}
return b.bus;
}
/**
* Removes a bus from being a thread default bus for any thread.
* <p>
* This is typically done when a bus has ended its lifecycle (i.e.: a call to
* {@link Bus#shutdown(boolean)} was invoked) and it wants to remove any reference to itself for any
* thread.
*
* @param bus the bus to remove
*/
public static void clearDefaultBusForAnyThread(final Bus bus) {
synchronized (THREAD_BUSSES) {
for (final Iterator<BusHolder> iterator = THREAD_BUSSES.values().iterator();
iterator.hasNext();) {
BusHolder itBus = iterator.next();
if (bus == null || itBus == null || itBus.bus == null
|| itBus.stale
|| bus.equals(itBus.bus)) {
if (itBus != null) {
itBus.bus = null;
//mark as stale so if a thread asks again, it will create a new one
itBus.stale = true;
}
//This will remove the BusHolder from the only place that should
//strongly reference it
iterator.remove();
}
}
}
}
/**
* Sets the default bus if a default bus is not already set.
*
* @param bus the default bus.
* @return true if the bus was not set and is now set
*/
public static synchronized boolean possiblySetDefaultBus(Bus bus) {
BusHolder b = getThreadBusHolder(false);
if (b.bus == null) {
b.bus = bus;
}
if (defaultBus == null) {
defaultBus = bus;
return true;
}
return false;
}
/**
* Create a new BusFactory The class of the BusFactory is determined by looking for the system propery:
* org.apache.cxf.bus.factory or by searching the classpath for:
* META-INF/services/org.apache.cxf.bus.factory
*
* @return a new BusFactory to be used to create Bus objects
*/
public static BusFactory newInstance() {
return newInstance(null);
}
/**
* Create a new BusFactory
*
* @param className The class of the BusFactory to create. If null, uses the default search algorithm.
* @return a new BusFactory to be used to create Bus objects
*/
public static BusFactory newInstance(String className) {
if (className == null) {
ClassLoader loader = Thread.currentThread().getContextClassLoader();
className = getBusFactoryClass(loader);
if (className == null && loader != BusFactory.class.getClassLoader()) {
className = getBusFactoryClass(BusFactory.class.getClassLoader());
}
}
if (className == null) {
className = BusFactory.DEFAULT_BUS_FACTORY;
}
try {
Class<? extends BusFactory> busFactoryClass = ClassLoaderUtils.loadClass(className, BusFactory.class)
.asSubclass(BusFactory.class);
return busFactoryClass.getConstructor().newInstance();
} catch (Exception ex) {
LogUtils.log(LOG, Level.SEVERE, "BUS_FACTORY_INSTANTIATION_EXC", ex);
throw new RuntimeException(ex);
}
}
protected void initializeBus(Bus bus) {
}
private static String getBusFactoryClass(ClassLoader classLoader) {
// next check system properties
String busFactoryClass = SystemPropertyAction.getPropertyOrNull(BusFactory.BUS_FACTORY_PROPERTY_NAME);
if (isValidBusFactoryClass(busFactoryClass)) {
return busFactoryClass;
}
try {
// next, check for the services stuff in the jar file
String serviceId = "META-INF/services/" + BusFactory.BUS_FACTORY_PROPERTY_NAME;
InputStream is;
if (classLoader == null) {
classLoader = Thread.currentThread().getContextClassLoader();
}
if (classLoader == null) {
is = ClassLoader.getSystemResourceAsStream(serviceId);
} else {
is = classLoader.getResourceAsStream(serviceId);
}
if (is == null) {
serviceId = "META-INF/cxf/" + BusFactory.BUS_FACTORY_PROPERTY_NAME;
if (classLoader == null) {
classLoader = Thread.currentThread().getContextClassLoader();
}
if (classLoader == null) {
is = ClassLoader.getSystemResourceAsStream(serviceId);
} else {
is = classLoader.getResourceAsStream(serviceId);
}
}
String busFactoryCondition = null;
if (is != null) {
try (BufferedReader rd = new BufferedReader(new InputStreamReader(is, StandardCharsets.UTF_8))) {
busFactoryClass = rd.readLine();
busFactoryCondition = rd.readLine();
}
}
if (isValidBusFactoryClass(busFactoryClass)
&& busFactoryCondition != null) {
try {
Class<?> cls = ClassLoaderUtils.loadClass(busFactoryClass, BusFactory.class)
.asSubclass(BusFactory.class);
if (busFactoryCondition.startsWith("#")) {
busFactoryCondition = busFactoryCondition.substring(1);
}
int idx = busFactoryCondition.indexOf(',');
while (idx != -1) {
cls.getClassLoader().loadClass(busFactoryCondition.substring(0, idx));
busFactoryCondition = busFactoryCondition.substring(idx + 1);
idx = busFactoryCondition.indexOf(',');
}
cls.getClassLoader().loadClass(busFactoryCondition);
} catch (ClassNotFoundException | NoClassDefFoundError e) {
busFactoryClass = DEFAULT_BUS_FACTORY;
}
}
} catch (Exception ex) {
LogUtils.log(LOG, Level.SEVERE, "FAILED_TO_DETERMINE_BUS_FACTORY_EXC", ex);
}
return busFactoryClass;
}
private static boolean isValidBusFactoryClass(String busFactoryClassName) {
return busFactoryClassName != null && !busFactoryClassName.isEmpty();
}
}