org.apache.catalina.loader.WebappLoader Maven / Gradle / Ivy
/*
* 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.catalina.loader;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;
import java.io.File;
import java.lang.reflect.Constructor;
import java.net.URL;
import java.net.URLClassLoader;
import java.nio.charset.StandardCharsets;
import javax.management.ObjectName;
import jakarta.servlet.ServletContext;
import org.apache.catalina.Context;
import org.apache.catalina.Globals;
import org.apache.catalina.LifecycleException;
import org.apache.catalina.LifecycleState;
import org.apache.catalina.Loader;
import org.apache.catalina.util.LifecycleMBeanBase;
import org.apache.catalina.util.ToStringUtil;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.apache.tomcat.jakartaee.ClassConverter;
import org.apache.tomcat.jakartaee.EESpecProfile;
import org.apache.tomcat.jakartaee.EESpecProfiles;
import org.apache.tomcat.util.ExceptionUtils;
import org.apache.tomcat.util.buf.UDecoder;
import org.apache.tomcat.util.compat.JreCompat;
import org.apache.tomcat.util.modeler.Registry;
import org.apache.tomcat.util.res.StringManager;
/**
* Classloader implementation which is specialized for handling web applications in the most efficient way, while being
* Catalina aware (all accesses to resources are made through {@link org.apache.catalina.WebResourceRoot}). This class
* loader supports detection of modified Java classes, which can be used to implement auto-reload support.
*
* This class loader is configured via the Resources children of its Context prior to calling start(). When
* a new class is required, these Resources will be consulted first to locate the class. If it is not present, the
* system class loader will be used instead.
*
* @author Craig R. McClanahan
* @author Remy Maucherat
*/
public class WebappLoader extends LifecycleMBeanBase implements Loader {
private static final Log log = LogFactory.getLog(WebappLoader.class);
// ----------------------------------------------------- Instance Variables
/**
* The class loader being managed by this Loader component.
*/
private WebappClassLoaderBase classLoader = null;
/**
* The Context with which this Loader has been associated.
*/
private Context context = null;
/**
* The "follow standard delegation model" flag that will be used to configure our ClassLoader.
*/
private boolean delegate = false;
/**
* The profile name which will be used by the converter, or null if not used. Any invalid profile value will default
* to the TOMCAT profile, which converts all packages used by Tomcat.
*/
private String jakartaConverter = null;
/**
* The Java class name of the ClassLoader implementation to be used. This class should extend WebappClassLoaderBase,
* otherwise, a different loader implementation must be used.
*/
private String loaderClass = ParallelWebappClassLoader.class.getName();
/**
* The string manager for this package.
*/
protected static final StringManager sm = StringManager.getManager(WebappLoader.class);
/**
* The property change support for this component.
*/
protected final PropertyChangeSupport support = new PropertyChangeSupport(this);
/**
* Classpath set in the loader.
*/
private String classpath = null;
// ------------------------------------------------------------- Properties
@Override
public ClassLoader getClassLoader() {
return classLoader;
}
@Override
public Context getContext() {
return context;
}
@Override
public void setContext(Context context) {
if (this.context == context) {
return;
}
if (getState().isAvailable()) {
throw new IllegalStateException(sm.getString("webappLoader.setContext.ise"));
}
// Process this property change
Context oldContext = this.context;
this.context = context;
support.firePropertyChange("context", oldContext, this.context);
}
@Override
public boolean getDelegate() {
return this.delegate;
}
@Override
public void setDelegate(boolean delegate) {
boolean oldDelegate = this.delegate;
this.delegate = delegate;
support.firePropertyChange("delegate", Boolean.valueOf(oldDelegate), Boolean.valueOf(this.delegate));
}
/**
* @return a non null String if the loader will attempt to use the Jakarta converter. The String is the name of the
* profile used for conversion.
*/
public String getJakartaConverter() {
return jakartaConverter;
}
/**
* Set the Jakarta converter.
*
* @param jakartaConverter The profile name which will be used by the converter Any invalid profile value will
* default to the TOMCAT profile, which converts all packages used by Tomcat.
*/
public void setJakartaConverter(String jakartaConverter) {
String oldJakartaConverter = this.jakartaConverter;
this.jakartaConverter = jakartaConverter;
support.firePropertyChange("jakartaConverter", oldJakartaConverter, this.jakartaConverter);
}
/**
* @return the ClassLoader class name.
*/
public String getLoaderClass() {
return this.loaderClass;
}
/**
* Set the ClassLoader class name.
*
* @param loaderClass The new ClassLoader class name
*/
public void setLoaderClass(String loaderClass) {
this.loaderClass = loaderClass;
}
/**
* Set the ClassLoader instance, without relying on reflection This method will also invoke
* {@link #setLoaderClass(String)} with {@code loaderInstance.getClass().getName()} as an argument
*
* @param loaderInstance The new ClassLoader instance to use
*/
public void setLoaderInstance(WebappClassLoaderBase loaderInstance) {
this.classLoader = loaderInstance;
setLoaderClass(loaderInstance.getClass().getName());
}
// --------------------------------------------------------- Public Methods
@Override
public void addPropertyChangeListener(PropertyChangeListener listener) {
support.addPropertyChangeListener(listener);
}
@Override
public void backgroundProcess() {
Context context = getContext();
if (context != null) {
if (context.getReloadable() && modified()) {
Thread currentThread = Thread.currentThread();
ClassLoader originalTccl = currentThread.getContextClassLoader();
try {
currentThread.setContextClassLoader(WebappLoader.class.getClassLoader());
context.reload();
} finally {
currentThread.setContextClassLoader(originalTccl);
}
}
}
}
public String[] getLoaderRepositories() {
if (classLoader == null) {
return new String[0];
}
URL[] urls = classLoader.getURLs();
String[] result = new String[urls.length];
for (int i = 0; i < urls.length; i++) {
result[i] = urls[i].toExternalForm();
}
return result;
}
public String getLoaderRepositoriesString() {
String repositories[] = getLoaderRepositories();
StringBuilder sb = new StringBuilder();
for (String repository : repositories) {
sb.append(repository).append(':');
}
return sb.toString();
}
/**
* Classpath, as set in org.apache.catalina.jsp_classpath context property
*
* @return The classpath
*/
public String getClasspath() {
return classpath;
}
@Override
public boolean modified() {
return classLoader != null ? classLoader.modified() : false;
}
@Override
public void removePropertyChangeListener(PropertyChangeListener listener) {
support.removePropertyChangeListener(listener);
}
@Override
public String toString() {
return ToStringUtil.toString(this, context);
}
/**
* Start associated {@link ClassLoader} and implement the requirements of
* {@link org.apache.catalina.util.LifecycleBase#startInternal()}.
*
* @exception LifecycleException if this component detects a fatal error that prevents this component from being
* used
*/
@Override
protected void startInternal() throws LifecycleException {
if (log.isDebugEnabled()) {
log.debug(sm.getString("webappLoader.starting"));
}
if (context.getResources() == null) {
log.info(sm.getString("webappLoader.noResources", context));
setState(LifecycleState.STARTING);
return;
}
// Construct a class loader based on our current repositories list
try {
classLoader = createClassLoader();
classLoader.setResources(context.getResources());
classLoader.setDelegate(this.delegate);
// Set Jakarta class converter
if (getJakartaConverter() != null) {
MigrationUtil.addJakartaEETransformer(classLoader, getJakartaConverter());
}
// Configure our repositories
setClassPath();
classLoader.start();
String contextName = context.getName();
if (!contextName.startsWith("/")) {
contextName = "/" + contextName;
}
ObjectName cloname =
new ObjectName(context.getDomain() + ":type=" + classLoader.getClass().getSimpleName() + ",host=" +
context.getParent().getName() + ",context=" + contextName);
Registry.getRegistry(null, null).registerComponent(classLoader, cloname, null);
} catch (Throwable t) {
t = ExceptionUtils.unwrapInvocationTargetException(t);
ExceptionUtils.handleThrowable(t);
throw new LifecycleException(sm.getString("webappLoader.startError"), t);
}
setState(LifecycleState.STARTING);
}
/**
* Stop associated {@link ClassLoader} and implement the requirements of
* {@link org.apache.catalina.util.LifecycleBase#stopInternal()}.
*
* @exception LifecycleException if this component detects a fatal error that prevents this component from being
* used
*/
@Override
protected void stopInternal() throws LifecycleException {
if (log.isDebugEnabled()) {
log.debug(sm.getString("webappLoader.stopping"));
}
setState(LifecycleState.STOPPING);
// Remove context attributes as appropriate
ServletContext servletContext = context.getServletContext();
servletContext.removeAttribute(Globals.CLASS_PATH_ATTR);
// Throw away our current class loader if any
if (classLoader != null) {
try {
classLoader.stop();
} finally {
classLoader.destroy();
}
// classLoader must be non-null to have been registered
try {
String contextName = context.getName();
if (!contextName.startsWith("/")) {
contextName = "/" + contextName;
}
ObjectName cloname =
new ObjectName(context.getDomain() + ":type=" + classLoader.getClass().getSimpleName() +
",host=" + context.getParent().getName() + ",context=" + contextName);
Registry.getRegistry(null, null).unregisterComponent(cloname);
} catch (Exception e) {
log.warn(sm.getString("webappLoader.stopError"), e);
}
}
classLoader = null;
}
// ------------------------------------------------------- Private Methods
/**
* Create associated classLoader.
*/
private WebappClassLoaderBase createClassLoader() throws Exception {
if (classLoader != null) {
return classLoader;
}
if (ParallelWebappClassLoader.class.getName().equals(loaderClass)) {
return new ParallelWebappClassLoader(context.getParentClassLoader());
}
Class clazz = Class.forName(loaderClass);
WebappClassLoaderBase classLoader = null;
ClassLoader parentClassLoader = context.getParentClassLoader();
Class[] argTypes = { ClassLoader.class };
Object[] args = { parentClassLoader };
Constructor constr = clazz.getConstructor(argTypes);
classLoader = (WebappClassLoaderBase) constr.newInstance(args);
return classLoader;
}
/**
* Set the appropriate context attribute for our class path. This is required only because Jasper depends on it.
*/
private void setClassPath() {
// Validate our current state information
if (context == null) {
return;
}
ServletContext servletContext = context.getServletContext();
if (servletContext == null) {
return;
}
StringBuilder classpath = new StringBuilder();
// Assemble the class path information from our class loader chain
ClassLoader loader = getClassLoader();
if (delegate && loader != null) {
// Skip the webapp loader for now as delegation is enabled
loader = loader.getParent();
}
while (loader != null) {
if (!buildClassPath(classpath, loader)) {
break;
}
loader = loader.getParent();
}
if (delegate) {
// Delegation was enabled, go back and add the webapp paths
loader = getClassLoader();
if (loader != null) {
buildClassPath(classpath, loader);
}
}
this.classpath = classpath.toString();
// Store the assembled class path as a servlet context attribute
servletContext.setAttribute(Globals.CLASS_PATH_ATTR, this.classpath);
}
private boolean buildClassPath(StringBuilder classpath, ClassLoader loader) {
if (loader instanceof URLClassLoader) {
URL repositories[] = ((URLClassLoader) loader).getURLs();
for (URL url : repositories) {
String repository = url.toString();
if (repository.startsWith("file://")) {
repository = UDecoder.URLDecode(repository.substring(7), StandardCharsets.UTF_8);
} else if (repository.startsWith("file:")) {
repository = UDecoder.URLDecode(repository.substring(5), StandardCharsets.UTF_8);
} else {
continue;
}
if (repository == null) {
continue;
}
if (classpath.length() > 0) {
classpath.append(File.pathSeparator);
}
classpath.append(repository);
}
} else if (loader == ClassLoader.getSystemClassLoader()) {
// From Java 9 the internal class loaders no longer extend
// URLCLassLoader
String cp = System.getProperty("java.class.path");
if (cp != null && cp.length() > 0) {
if (classpath.length() > 0) {
classpath.append(File.pathSeparator);
}
classpath.append(cp);
}
return false;
} else {
// Ignore Graal "unknown" classloader
if (!JreCompat.isGraalAvailable()) {
log.info(sm.getString("webappLoader.unknownClassLoader", loader, loader.getClass()));
}
return false;
}
return true;
}
@Override
protected String getDomainInternal() {
return context.getDomain();
}
@Override
protected String getObjectNameKeyProperties() {
StringBuilder name = new StringBuilder("type=Loader");
name.append(",host=");
name.append(context.getParent().getName());
name.append(",context=");
String contextName = context.getName();
if (!contextName.startsWith("/")) {
name.append('/');
}
name.append(contextName);
return name.toString();
}
/**
* Implemented in a sub-class so EESpecProfile and EESpecProfiles are not loaded unless a profile is configured.
* Otherwise, tomcat-embed-core.jar has a runtime dependency on the migration tool whether it is used or not.
*/
private static class MigrationUtil {
public static void addJakartaEETransformer(WebappClassLoaderBase webappClassLoader, String profileName) {
EESpecProfile profile = null;
try {
profile = EESpecProfiles.valueOf(profileName);
} catch (IllegalArgumentException ignored) {
// Use default value
log.warn(sm.getString("webappLoader.unknownProfile", profileName));
}
webappClassLoader.addTransformer(profile != null ? new ClassConverter(profile) : new ClassConverter());
}
}
}