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 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
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 * Copyright 2007-2008 Sun Microsystems, Inc. All rights reserved.
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 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License. You can obtain
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package org.atmosphere.cpr;

import org.atmosphere.container.BlockingIOCometSupport;
import org.atmosphere.container.GlassFishWebSocketSupport;
import org.atmosphere.container.GlassFishv2CometSupport;
import org.atmosphere.container.GrizzlyCometSupport;
import org.atmosphere.container.JBossWebCometSupport;
import org.atmosphere.container.Jetty7CometSupport;
import org.atmosphere.container.Jetty8WebSocketSupport;
import org.atmosphere.container.JettyCometSupport;
import org.atmosphere.container.Servlet30Support;
import org.atmosphere.container.TomcatCometSupport;
import org.atmosphere.container.WebLogicCometSupport;
import org.atmosphere.cpr.AtmosphereServlet.AtmosphereConfig;
import org.atmosphere.util.LoggerUtils;

import java.util.LinkedList;
import java.util.List;
import java.util.logging.Logger;

/**
 * This is the default implementation of @link {CometSupportResolver}
 *
 * @author Viktor Klang
 */
public class DefaultCometSupportResolver implements CometSupportResolver {

    public final static String SERVLET_30 = "javax.servlet.AsyncListener";
    public final static String GLASSFISH_V2 = "com.sun.enterprise.web.PEWebContainer";
    public final static String TOMCAT = "org.apache.coyote.http11.Http11NioProcessor";
    public final static String JBOSS_5 = "org.jboss.";
    public final static String JETTY = "org.mortbay.util.ajax.Continuation";
    public final static String JETTY_7 = "org.eclipse.jetty.servlet.ServletContextHandler";
    public final static String JETTY_8 = "org.eclipse.jetty.continuation.Servlet3Continuation";
    public final static String GRIZZLY = "com.sun.grizzly.http.servlet.ServletAdapter";
    public final static String WEBLOGIC = "weblogic.servlet.http.FutureResponseModel";
    public final static String JBOSSWEB = "org.apache.catalina.connector.HttpEventImpl";
    public final static Logger logger = LoggerUtils.getLogger();
    public final static String GRIZZLY_WEBSOCKET = "com.sun.grizzly.websockets.WebSocketEngine";

    private final AtmosphereConfig config;

    public DefaultCometSupportResolver(final AtmosphereConfig config) {
        this.config = config;
    }

    /**
     * Convenience method that tests if a class with the given FQN is present on the classpath
     *
     * @param testClass
     * @return true if the class is present
     */
    protected boolean testClassExists(final String testClass) {
        try {
            return testClass != null && testClass.length() > 0 && Class.forName(testClass) != null;
        } catch (ClassNotFoundException ex) {
            return false;
        } catch (NoClassDefFoundError ex) {
            return false;
        }
    }

    /**
     * Returns a list of comet support by containers available on the classpath
     *
     * @return
     */
    public List> detectContainersPresent() {
        return new LinkedList>() {
            {
                if (testClassExists(GLASSFISH_V2))
                    add(GlassFishv2CometSupport.class);

                if (testClassExists(JETTY))
                    add(JettyCometSupport.class);

                if (testClassExists(JETTY_7))
                    add(Jetty7CometSupport.class);

                if (testClassExists(JETTY_8))
                    add(Jetty7CometSupport.class);

                if (testClassExists(JBOSSWEB))
                    add(JBossWebCometSupport.class);

                if (testClassExists(TOMCAT) || testClassExists(JBOSS_5))
                    add(TomcatCometSupport.class);

                if (testClassExists(GRIZZLY))
                    add(GrizzlyCometSupport.class);

                if (testClassExists(WEBLOGIC))
                    add(WebLogicCometSupport.class);
            }
        };
    }

    public List> detectWebSocketPresent() {
        List l =  new LinkedList>() {
            {
                if (testClassExists(JETTY_8))
                    add(Jetty8WebSocketSupport.class);

                if (testClassExists(GRIZZLY_WEBSOCKET))
                    add(GlassFishWebSocketSupport.class);

            }
        };

        if (l.isEmpty()) {
            return detectContainersPresent();
        }
        return l;
    }

    /**
     * This method is used to determine the default CometSupport if all else fails
     *
     * @param preferBlocking
     * @return
     */
    public CometSupport defaultCometSupport(final boolean preferBlocking) {
        if (!preferBlocking && testClassExists(SERVLET_30)) {
            return new Servlet30Support(config);
        } else {
            return new BlockingIOCometSupport(config);
        }
    }

    /**
     * Given a Class of something that extends CometSupport, it tries to return an instance of that class
     * 

* The class has to have a visible constructor with the signature (@link {AtmosphereConfig}) * * @param targetClass * @return an instance of the specified class */ public CometSupport newCometSupport(final Class targetClass) { try { return (CometSupport) targetClass.getDeclaredConstructor(new Class[]{AtmosphereConfig.class}).newInstance(new Object[]{config}); } catch (final Exception e) { logger.warning(e.getMessage()); throw new IllegalArgumentException("Comet support class " + targetClass.getCanonicalName() + " has bad signature.", e); } } public CometSupport newCometSupport(final String targetClassFQN) { try { ClassLoader cl = Thread.currentThread().getContextClassLoader(); return (CometSupport) cl.loadClass(targetClassFQN).getDeclaredConstructor(new Class[]{AtmosphereConfig.class}).newInstance(new Object[]{config}); } catch (final Exception e) { logger.warning(e.getMessage()); throw new IllegalArgumentException("Comet support class " + targetClassFQN + " has bad signature.", e); } } /** * This method is the general interface to the outside world * * @param useNativeIfPossible - should the resolver try to use a native container comet support if present? * @param defaultToBlocking - should the resolver default to blocking IO comet support? * @return an instance of CometSupport */ public CometSupport resolve(final boolean useNativeIfPossible, final boolean defaultToBlocking) { final CometSupport servletAsyncSupport = defaultCometSupport(defaultToBlocking); final CometSupport nativeSupport; if (!defaultToBlocking && (useNativeIfPossible || servletAsyncSupport.getClass().getName().equals(BlockingIOCometSupport.class.getName()))) { nativeSupport = resolveNativeCometSupport(detectContainersPresent()); return nativeSupport == null ? servletAsyncSupport : nativeSupport; } return servletAsyncSupport; } public CometSupport resolve(boolean useNativeIfPossible, boolean defaultToBlocking, boolean useWebsocketIfPossible) { if (!useWebsocketIfPossible) { return resolve(useNativeIfPossible, defaultToBlocking); } else { return resolveWebSocket(detectWebSocketPresent()); } } public CometSupport resolveWebSocket(final java.util.List> available) { if (available == null || available.isEmpty()) return null; else return newCometSupport(available.get(0)); } /** * This method is called to determine which native comet support to the used * * @param available * @return the result of @link {resolveMultipleNativeSupportConflict} if there are more than 1 item in the list of available ontainers */ protected CometSupport resolveNativeCometSupport(final java.util.List> available) { if (available == null || available.isEmpty()) return null; else if (available.size() == 1) return newCometSupport(available.get(0)); else return resolveMultipleNativeSupportConflict(available); } /** * This method is called if there are more than one potential native container in scope * * @return a CometSupport instance */ protected CometSupport resolveMultipleNativeSupportConflict(final List> available) { final StringBuilder b = new StringBuilder("Found multiple containers, please specify which one to use: "); for (Class cs : available) { b.append((cs != null) ? cs.getCanonicalName() : "null").append(", "); } b.append(" until you do, Atmosphere will use:" + available.get(0)); logger.warning(b.toString()); return newCometSupport(available.get(0)); } }





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