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* 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
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*
* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.cayenne.configuration.web;
import java.io.IOException;
import java.util.Collection;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import org.apache.cayenne.configuration.CayenneRuntime;
import org.apache.cayenne.configuration.server.ServerModule;
import org.apache.cayenne.configuration.server.ServerRuntime;
import org.apache.cayenne.di.Module;
/**
* A filter that creates a Cayenne server runtime, possibly including custom modules. By
* default runtime includes {@link ServerModule} and {@link WebModule}. Any
* custom modules are loaded after the two standard ones to allow custom service
* overrides. Filter initialization parameters:
* <ul>
* <li>configuration-location - (optional) a name of Cayenne configuration XML file that
* will be used to load Cayenne stack. If missing, the filter name will be used to derive
* the location. ".xml" extension will be appended to the filter name to get the location,
* so a filter named "cayenne-foo" will result in location "cayenne-foo.xml".
* <li>extra-modules - (optional) a comma or space-separated list of class names, with
* each class implementing {@link Module} interface. These are the custom modules loaded
* after the two standard ones that allow users to override any Cayenne runtime aspects,
* e.g. {@link RequestHandler}. Each custom module must have a no-arg constructor.
* </ul>
* <p>
* CayenneFilter is a great utility to quickly start a Cayenne application. More advanced
* apps most likely will not use it, relying on their own configuration mechanism (such as
* Guice, Spring, etc.)
*
* @since 3.1
*/
public class CayenneFilter implements Filter {
protected ServletContext servletContext;
public void init(FilterConfig config) throws ServletException {
this.servletContext = config.getServletContext();
WebConfiguration configAdapter = new WebConfiguration(config);
String configurationLocation = configAdapter.getConfigurationLocation();
Collection<Module> modules = configAdapter.createModules(new WebModule());
ServerRuntime runtime = new ServerRuntime(
configurationLocation,
modules);
WebUtil.setCayenneRuntime(config.getServletContext(), runtime);
}
public void destroy() {
CayenneRuntime runtime = WebUtil.getCayenneRuntime(servletContext);
if (runtime != null) {
runtime.shutdown();
}
}
public void doFilter(
ServletRequest request,
ServletResponse response,
FilterChain chain) throws IOException, ServletException {
CayenneRuntime runtime = WebUtil.getCayenneRuntime(servletContext);
RequestHandler handler = runtime.getInjector().getInstance(RequestHandler.class);
handler.requestStart(request, response);
try {
chain.doFilter(request, response);
}
finally {
handler.requestEnd(request, response);
}
}
}