edu.uiuc.ncsa.security.servlet.Bootstrapper Maven / Gradle / Ivy
package edu.uiuc.ncsa.security.servlet;
import edu.uiuc.ncsa.security.core.exceptions.ConfigurationException;
import edu.uiuc.ncsa.security.core.util.ConfigurationLoader;
import org.apache.commons.configuration.tree.ConfigurationNode;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
/**
* This class controls the loading of the correct boot strapper, which in turn is
* charged with translating the configuration into usable objects. This should be
* set as a context listener in your web.xml. A Typical entry looks like this:
*
* <listener>
* <listener-class>full.pack.age.name.to.MyBootstrapper</listener-class>
* </listener>
*
* Simply supply an instance of
* the your bootstrapper, returned by {@link #getConfigurationLoader(javax.servlet.ServletContext)}
* and this will in turn stick it into your servlets (by putting it in the
* environemtn for the top-level {@link AbstractServlet} which everything should inherit from.
* Note that this
* is designed for a single use in a web application. The environment will be static
* and shared by all the servlets in a single web application.
* Created by Jeff Gaynor
* on 3/21/12 at 10:59 AM
*/
public abstract class Bootstrapper implements ServletContextListener {
@Override
public void contextDestroyed(ServletContextEvent sce) {
// no op. Override if needed.
}
@Override
public void contextInitialized(ServletContextEvent event) {
try {
AbstractServlet.setConfigurationLoader(getConfigurationLoader(event.getServletContext()));
} catch (Exception e) {
// one of the few places to actually print the stack trace, since if it bombs here it will be well before
// Tomcat has loaded much of anything and no or limited logging will be available. Make sure
// someone can actually find a message if there is a problem.
e.printStackTrace();
throw new ConfigurationException("Error: could not load configuration", e);
}
}
public abstract ConfigurationLoader getConfigurationLoader(ServletContext servletContext) throws Exception;
public abstract ConfigurationLoader getConfigurationLoader(ConfigurationNode node) throws ConfigurationException;
}