/extras/guice/src/main/java/org/atmosphere/guice/AtmosphereGuiceServlet.java

/*
 * Copyright 2011 Jeanfrancois Arcand
 *
 * Licensed 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.
 */
/*
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 1997-2007 Sun Microsystems, Inc. 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://jersey.dev.java.net/CDDL+GPL.html
 * or jersey/legal/LICENSE.txt.  See the License for the specific
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 * When distributing the software, include this License Header Notice in each
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 * as provided by Sun in the GPL Version 2 section of the License file that
 * accompanied this code.  If applicable, add the following below the License
 * Header, with the fields enclosed by brackets [] replaced by your own
 * identifying information: "Portions Copyrighted [year]
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 * Version 2] license."  If you don't indicate a single choice of license, a
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 * and therefore, elected the GPL Version 2 license, then the option applies
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 */

package org.atmosphere.guice;

import com.google.inject.Injector;
import com.google.inject.Key;
import com.google.inject.TypeLiteral;
import com.google.inject.name.Names;
import com.sun.jersey.guice.spi.container.servlet.GuiceContainer;
import org.atmosphere.cpr.AtmosphereServlet;
import org.atmosphere.handler.ReflectorServletProcessor;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import java.util.Map;

/**
 * Google Guice Integration. To use it, just do in web.xml:
 *
 * <blockquote><code>
     &lt;web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
        xmlns:j2ee = "http://java.sun.com/xml/ns/j2ee"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee    http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"&gt;
        &lt;listener&gt;
            &lt;listener-class&gt;org.atmosphere.samples.guice.GuiceChatConfig&lt;/listener-class&gt;
        &lt;/listener&gt;
        &lt;description&gt;Atmosphere Chat&lt;/description&gt;
        &lt;display-name&gt;Atmosphere Chat&lt;/display-name&gt;
        &lt;servlet&gt;
            &lt;description&gt;AtmosphereServlet&lt;/description&gt;
            &lt;servlet-name&gt;AtmosphereServlet&lt;/servlet-name&gt;
            &lt;servlet-class&gt;org.atmosphere.guice.AtmosphereGuiceServlet&lt;/servlet-class&gt;
            &lt;load-on-startup&gt;0&lt;/load-on-startup&gt;
        &lt;/servlet&gt;
        &lt;servlet-mapping&gt;
            &lt;servlet-name&gt;AtmosphereServlet&lt;/servlet-name&gt;
            &lt;url-pattern&gt;/chat/*&lt;/url-pattern&gt;
        &lt;/servlet-mapping&gt;
    &lt;/web-app&gt;

    and then

    public class GuiceConfig extends GuiceServletContextListener {

        @Override
        protected Injector getInjector() {
            return Guice.createInjector(new ServletModule() {
                @Override
                protected void configureServlets() {
                    bind(PubSubTest.class);
                    bind(new TypeLiteral&lt;Map&lt;String, String&gt;&gt;() {
                        }).annotatedWith(Names.named(AtmosphereGuiceServlet.JERSEY_PROPERTIES)).toInstance(
                            Collections.&lt;String, String>emptyMap());
                }
            });
        }
    }
 </code></blockquote>
 *
 * @author Jeanfrancois Arcand
 * @author Richard Wallace
 */
public class AtmosphereGuiceServlet extends AtmosphereServlet {

    private static final Logger logger = LoggerFactory.getLogger(AtmosphereGuiceServlet.class);
    public static final String JERSEY_PROPERTIES = AtmosphereGuiceServlet.class.getName() + ".properties";
    private static final String GUICE_FILTER = "com.google.inject.servlet.GuiceFilter";

    private boolean guiceInstalled = false;

    /**
     * Install Guice event if other extension has been already installed.
     * @param sc {@link javax.servlet.ServletConfig}
     * @throws ServletException
     */
    @Override
    protected void loadConfiguration(ServletConfig sc) throws ServletException {
        super.loadConfiguration(sc);

        if (!guiceInstalled) {
            detectSupportedFramework(sc);
        }
    }

    /**
     * Auto-detect Jersey when no atmosphere.xml file are specified.
     *
     * @param sc {@link javax.servlet.ServletConfig}
     * @return true if Jersey classes are detected
     */
    @Override
    protected boolean detectSupportedFramework(ServletConfig sc) {
        Injector injector = (Injector) config.getServletContext().getAttribute(Injector.class.getName());
        GuiceContainer guiceServlet = injector.getInstance(GuiceContainer.class);

        setUseStreamForFlushingComments(false);
        ReflectorServletProcessor rsp = new ReflectorServletProcessor();
        setDefaultBroadcasterClassName(JERSEY_BROADCASTER);
        setUseStreamForFlushingComments(true);

        rsp.setServlet(guiceServlet);
        rsp.setFilterClassName(GUICE_FILTER);
        getAtmosphereConfig().setSupportSession(false);

        String mapping = sc.getInitParameter(PROPERTY_SERVLET_MAPPING);
        if (mapping == null) {
            mapping = "/*";
        }

        try {
            Map<String, String> props = injector.getInstance(
                    Key.get(new TypeLiteral<Map<String, String>>() {},Names.named(JERSEY_PROPERTIES)));


            if (props != null) {
                for (String p : props.keySet()) {
                    addInitParameter(p, props.get(p));
                }
            }
        } catch (Exception ex) {
            // Do not fail
            logger.debug("failed to add Jersey init parameters to Atmosphere servlet", ex);
        }

        addAtmosphereHandler(mapping, rsp);
        guiceInstalled = true;
        return true;
    }
}