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ContainerManager.java
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ContainerManager.java
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/**
* 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.gservlet;
import static org.gservlet.Constants.HANDLERS;
import static org.gservlet.Constants.SCRIPTS_FOLDER;
import java.io.File;
import java.lang.reflect.Proxy;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.EnumSet;
import java.util.EventListener;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.DispatcherType;
import javax.servlet.FilterRegistration;
import javax.servlet.MultipartConfigElement;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextAttributeListener;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;
import javax.servlet.ServletRequestAttributeListener;
import javax.servlet.ServletRequestListener;
import javax.servlet.ServletSecurityElement;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.ServletSecurity;
import javax.servlet.http.HttpSessionAttributeListener;
import javax.servlet.http.HttpSessionIdListener;
import javax.servlet.http.HttpSessionListener;
import org.gservlet.annotation.ContextAttributeListener;
import org.gservlet.annotation.ContextListener;
import org.gservlet.annotation.Filter;
import org.gservlet.annotation.RequestAttributeListener;
import org.gservlet.annotation.RequestListener;
import org.gservlet.annotation.Servlet;
import org.gservlet.annotation.SessionAttributeListener;
import org.gservlet.annotation.SessionIdListener;
import org.gservlet.annotation.SessionListener;
import groovy.util.ScriptException;
/**
*
* The ContainerManager manages the registration and the reloading of a servlet,
* filter or listener into the web container
*
* @author Mamadou Lamine Ba
*
*/
public class ContainerManager {
/**
* The servlet context object
*/
protected final ServletContext context;
/**
* The map of dynamic invocation handlers
*/
protected final Map<String, DynamicInvocationHandler> handlers = new HashMap<>();
/**
* The script manager object
*/
protected ScriptManager scriptManager;
/**
* The logger object
*/
protected final Logger logger = Logger.getLogger(getClass().getName());
/**
*
* Constructs a ContainerManager for the given servlet context
*
* @param context the servlet context
* @throws ServletException the ServletException
*
*/
public ContainerManager(ServletContext context) throws ServletException {
try {
this.context = context;
context.setAttribute(HANDLERS, handlers);
} catch (Exception e) {
throw new ServletException(e);
}
}
/**
*
* Initializes the application for the given directory
*
* @param directory the scripts parent directory
* @param listeners the ScriptListener list
* @throws ServletException the ServletException
* @throws ScriptException the ScriptException
*
*/
public void init(String directory, List<ScriptListener> listeners) throws ServletException, ScriptException {
File folder = new File(directory + File.separator + SCRIPTS_FOLDER);
scriptManager = new ScriptManager(folder);
scriptManager.addScriptListeners(listeners);
if (folder.exists()) {
loadScripts(folder);
watch(folder);
}
}
/**
*
* Loads and registers the servlets, filters or listeners
*
* @param folder the scripts folder
* @throws ServletException the ServletException
* @throws ScriptException the ScriptException
*
*/
protected void loadScripts(File folder) throws ServletException, ScriptException {
for (File file : folder.listFiles()) {
if (file.isFile()) {
register(scriptManager.createObject(file));
} else {
loadScripts(file);
}
}
}
/**
*
* Registers a servlet, filter or listener into the web container
*
* @param object the object
* @throws ServletException the ServletException
*
*/
public void register(Object object) throws ServletException {
if (isServlet(object)) {
addServlet(object);
} else if (isFilter(object)) {
addFilter(object);
} else if (isListener(object)) {
addListener(object);
}
}
/**
*
* Registers a servlet into the web container
*
* @param object the servlet object
* @throws ServletException the ServletException
*
*/
protected void addServlet(Object object) throws ServletException {
Servlet annotation = object.getClass().getAnnotation(Servlet.class);
String name = object.getClass().getName();
ServletRegistration registration = context.getServletRegistration(name);
if (registration == null) {
DynamicInvocationHandler handler = new DynamicInvocationHandler(object);
Object servlet = createProxy(handler, javax.servlet.Servlet.class);
handlers.put(name, handler);
ServletRegistration.Dynamic dynamic = context.addServlet(name, (javax.servlet.Servlet) servlet);
dynamic.setLoadOnStartup(annotation.loadOnStartup());
dynamic.setAsyncSupported(annotation.asyncSupported());
if (annotation.value().length > 0) {
dynamic.addMapping(annotation.value());
}
if (annotation.urlPatterns().length > 0) {
dynamic.addMapping(annotation.urlPatterns());
}
Arrays.stream(annotation.initParams())
.forEach(param -> dynamic.setInitParameter(param.name(), param.value()));
MultipartConfig multiPartConfig = object.getClass().getAnnotation(MultipartConfig.class);
if (multiPartConfig != null) {
dynamic.setMultipartConfig(new MultipartConfigElement(multiPartConfig));
}
ServletSecurity servletSecurity = object.getClass().getAnnotation(ServletSecurity.class);
if (servletSecurity != null) {
dynamic.setServletSecurity(new ServletSecurityElement(servletSecurity));
}
} else {
String message = "The servlet with the name " + name
+ " has already been registered. Please use a different name or package";
throw new ServletException(message);
}
}
/**
*
* Registers a filter into the web container
*
* @param object the filter object
* @throws ServletException the ServletException
*
*/
protected void addFilter(Object object) throws ServletException {
Filter annotation = object.getClass().getAnnotation(Filter.class);
String name = object.getClass().getName();
FilterRegistration registration = context.getFilterRegistration(name);
if (registration == null) {
DynamicInvocationHandler handler = new DynamicInvocationHandler(object);
Object filter = createProxy(handler, javax.servlet.Filter.class);
handlers.put(name, handler);
FilterRegistration.Dynamic dynamic = context.addFilter(name, (javax.servlet.Filter) filter);
dynamic.setAsyncSupported(annotation.asyncSupported());
Collection<DispatcherType> dispatcherTypes = Arrays.asList(annotation.dispatcherTypes());
if (annotation.value().length > 0) {
dynamic.addMappingForUrlPatterns(EnumSet.copyOf(dispatcherTypes), true, annotation.value());
}
if (annotation.urlPatterns().length > 0) {
dynamic.addMappingForUrlPatterns(EnumSet.copyOf(dispatcherTypes), true, annotation.urlPatterns());
}
Arrays.stream(annotation.initParams())
.forEach(param -> dynamic.setInitParameter(param.name(), param.value()));
} else {
String message = "The filter with the name " + name
+ " has already been registered. Please use a different name or package";
throw new ServletException(message);
}
}
/**
*
* Registers a listener into the web container
*
* @param object the listener object
*
*/
protected void addListener(Object object) {
DynamicInvocationHandler handler = new DynamicInvocationHandler(object);
Object listener = null;
if (object instanceof ServletContextAttributeListener) {
listener = createProxy(handler, ServletContextAttributeListener.class);
} else if (object instanceof ServletRequestListener) {
listener = createProxy(handler, ServletRequestListener.class);
} else if (object instanceof ServletRequestAttributeListener) {
listener = createProxy(handler, ServletRequestAttributeListener.class);
} else if (object instanceof HttpSessionListener) {
listener = createProxy(handler, HttpSessionListener.class);
} else if (object instanceof HttpSessionAttributeListener) {
listener = createProxy(handler, HttpSessionAttributeListener.class);
} else if (object instanceof HttpSessionIdListener) {
listener = createProxy(handler, HttpSessionIdListener.class);
}
if (listener != null) {
context.addListener((EventListener) listener);
} else if (object instanceof AbstractContextListener) {
AbstractContextListener contextListener = (AbstractContextListener) object;
contextListener.contextInitialized(new ServletContextEvent(context));
}
handlers.put(object.getClass().getName(), handler);
}
/**
*
* Creates a Proxy object
*
* @param handler the handler
*
* @param clazz the class
*
* @return the Proxy object
*
*/
protected Object createProxy(DynamicInvocationHandler handler, Class<?> clazz) {
return Proxy.newProxyInstance(this.getClass().getClassLoader(), new Class[] { clazz }, handler);
}
/**
*
* Watches the scripts folder for file changes
*
* @param folder the scripts folder
*
*/
protected void watch(File folder) {
new FileWatcher(folder).addFileListener(new FileAdapter() {
@Override
public void onCreated(FileEvent event) {
File file = event.getFile();
if (file.isFile()) {
process(file);
}
}
@Override
public void onModified(FileEvent event) {
onCreated(event);
}
}).watch();
}
/**
*
* Processes a script file
*
* @param file the given file
*
*/
protected void process(File file) {
try {
logger.log(Level.INFO, "processing script {0}", file.getName());
process(scriptManager.createObject(file));
} catch (Exception e) {
logger.log(Level.SEVERE, "exception when reloading script", e);
}
}
/**
*
* Processes an object
*
* @param object the given object
* @throws ServletException the ServletException
* @throws ScriptException the ScriptException
*
*/
protected void process(Object object) throws ServletException, ScriptException {
if (isServlet(object)) {
reloadServlet((AbstractServlet) object);
} else if (isFilter(object)) {
reloadFilter((AbstractFilter) object);
} else if (isListener(object)) {
reload(object);
if (object instanceof AbstractContextListener) {
AbstractContextListener contextListener = (AbstractContextListener) object;
contextListener.contextInitialized(new ServletContextEvent(context));
}
} else {
reloadScripts(scriptManager.getFolder());
}
}
/**
*
* Reloads a servlet, filter or a listener into the web container
*
* @param object the object to be reloaded
*
*/
protected void reload(Object object) {
DynamicInvocationHandler handler = handlers.get(object.getClass().getName());
if (handler != null) {
handler.setTarget(object);
}
}
/**
*
* Reloads a servlet
*
* @param servlet the servlet to be reloaded
* @throws ServletException the ServletException
*
*/
protected void reloadServlet(AbstractServlet servlet) throws ServletException {
reload(servlet);
DefaultServletConfig config = new DefaultServletConfig();
config.setServletContext(context);
Servlet annotation = servlet.getClass().getAnnotation(Servlet.class);
Arrays.stream(annotation.initParams()).forEach(param -> config.addInitParameter(param.name(), param.value()));
servlet.init(config);
}
/**
*
* Reloads a filter
*
* @param filter the filter to be reloaded
* @throws ServletException the ServletException
*
*/
protected void reloadFilter(AbstractFilter filter) throws ServletException {
reload(filter);
DefaultFilterConfig config = new DefaultFilterConfig();
config.setServletContext(context);
Filter annotation = filter.getClass().getAnnotation(Filter.class);
Arrays.stream(annotation.initParams()).forEach(param -> config.addInitParameter(param.name(), param.value()));
filter.init(config);
}
/**
*
* Reloads the servlets, filters or listeners
*
* @param folder the scripts folder
* @throws ServletException the ServletException
* @throws ScriptException the ScriptException
*
*/
protected void reloadScripts(File folder) throws ServletException, ScriptException {
for (File file : folder.listFiles()) {
if (file.isFile()) {
Object object = scriptManager.createObject(file);
if (isServlet(object) || isFilter(object) || isListener(object)) {
process(object);
}
} else {
reloadScripts(file);
}
}
}
/**
*
* Calls the destroy method of the ServletContextListener objects when the
* ServletContext is about to be shutdown
*
*/
public void stop() {
handlers.values().forEach(handler -> {
Object target = handler.getTarget();
if (target instanceof AbstractContextListener) {
AbstractContextListener contextListener = (AbstractContextListener) target;
contextListener.contextDestroyed(new ServletContextEvent(context));
}
});
handlers.clear();
}
/**
*
* Returns the map of dynamic invocation handlers
*
* @return the map of dynamic invocation handlers
*/
public Map<String, DynamicInvocationHandler> getHandlers() {
return Collections.unmodifiableMap(handlers);
}
/**
*
* Returns the script manager
*
* @return the script manager
*/
public ScriptManager getScriptManager() {
return scriptManager;
}
/**
*
* Checks if the given object is a servlet
*
* @param object the given object
*
* @return true if the given object is a servlet
*/
protected boolean isServlet(Object object) {
return object.getClass().isAnnotationPresent(Servlet.class);
}
/**
*
* Checks if the given object is a filter
*
* @param object the given object
*
* @return true if the given object is a filter
*/
protected boolean isFilter(Object object) {
return object.getClass().isAnnotationPresent(Filter.class);
}
/**
*
* Checks if the given object is a listener
*
* @param object the given object
*
* @return true if the given object is a listener
*/
protected boolean isListener(Object object) {
Class<?> clazz = object.getClass();
return clazz.isAnnotationPresent(ContextListener.class)
|| clazz.isAnnotationPresent(ContextAttributeListener.class)
|| clazz.isAnnotationPresent(RequestListener.class)
|| clazz.isAnnotationPresent(RequestAttributeListener.class)
|| clazz.isAnnotationPresent(SessionListener.class)
|| clazz.isAnnotationPresent(SessionAttributeListener.class)
|| clazz.isAnnotationPresent(SessionIdListener.class);
}
}