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Micro Distribution of the Payara Project for IBM JDK
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/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 2011-2012 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
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 * GPL Classpath Exception:
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 */

package org.glassfish.sse.impl;

import javax.servlet.ServletContainerInitializer;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;
import javax.servlet.annotation.HandlesTypes;
import java.util.*;

import org.glassfish.sse.api.*;

/**
 * Registers a context listener to get ServletContext
 *
 * Registers a servlet dynamically if there are ServerSentEventHandlers in
 * an application.
 *
 * @author Jitendra Kotamraju
 */
@HandlesTypes(ServerSentEvent.class)
public class ServerSentEventServletContainerInitializer implements ServletContainerInitializer {

    public void onStartup(Set> set, ServletContext ctx) throws ServletException {
        if (set == null || set.isEmpty()) {
            return;
        }

        // Check if there is already a servlet for server sent events
        Map registrations = ctx.getServletRegistrations();
        for(ServletRegistration reg : registrations.values()) {
            if (reg.getClass().equals(ServerSentEventServlet.class)) {
                return;
            }
        }

        // Collect all the url patterns for server sent event handlers
        List urlPatternList = new ArrayList();

        for(Class clazz : set) {
            if (ServerSentEventHandler.class.isAssignableFrom(clazz)) {
                ServerSentEvent handler = clazz.getAnnotation(ServerSentEvent.class);
                if (handler == null) {
                    throw new RuntimeException("ServerSentEventHandler Class "+clazz+" doesn't have WebHandler annotation");
                }
                urlPatternList.add(handler.value());
            }
        }

        // Register a servlet for all the url patterns of server sent event handler
        if (!urlPatternList.isEmpty()) {
            ServletRegistration.Dynamic reg = ctx.addServlet("sse servlet", ServerSentEventServlet.class);
            reg.setAsyncSupported(true);
            reg.addMapping(urlPatternList.toArray(new String[urlPatternList.size()]));
        }
    }

}