package com.baeldung.web;

import java.util.Set;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;

import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.ContextLoaderListener;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.context.support.GenericWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;

public class WebAppInitializer implements WebApplicationInitializer {
    
    @Override
    public void onStartup(final ServletContext sc) throws ServletException {

        final AnnotationConfigWebApplicationContext root = new AnnotationConfigWebApplicationContext();
        root.scan("com.baeldung.spring");

        sc.addListener(new ContextLoaderListener(root));

        final ServletRegistration.Dynamic appServlet = sc.addServlet("spring", new DispatcherServlet(new GenericWebApplicationContext()));
        appServlet.setLoadOnStartup(1);

        final Set<String> mappingConflicts = appServlet.addMapping("/");
        if (!mappingConflicts.isEmpty()) {
            throw new IllegalStateException("'appServlet' could not be mapped to '/' due " + "to an existing mapping. This is a known issue under Tomcat versions " + "<= 7.0.14; see https://issues.apache.org/bugzilla/show_bug.cgi?id=51278");
        }
    }
}