PublisherInterceptor.java

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 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
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 *
 * This software is distributed in the hope that it will be useful,
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
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package org.jboss.test.osgi.example.interceptor.bundle;

import javax.servlet.http.HttpServlet;

import org.jboss.logging.Logger;
import org.jboss.osgi.deployment.interceptor.AbstractLifecycleInterceptor;
import org.jboss.osgi.deployment.interceptor.InvocationContext;
import org.jboss.osgi.deployment.interceptor.LifecycleInterceptorException;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;
import org.osgi.service.http.HttpService;

/**
 * An interceptor that publishes HttpMetadata.
 * 
 * @author thomas.diesler@jboss.com
 * @since 23-Oct-2009
 */
public class PublisherInterceptor extends AbstractLifecycleInterceptor {
    // Provide logging
    private static final Logger log = Logger.getLogger(PublisherInterceptor.class);

    PublisherInterceptor() {
        // Add the required input
        addInput(ParserInterceptor.HTTP_METADATA_KEY);
    }

    public void invoke(int state, InvocationContext context) {
        // HttpMetadata is guaratied to be available because we registered
        // this type as required input
        HttpMetadata metadata = context.getAttachment(ParserInterceptor.HTTP_METADATA_KEY);

        // Register HttpMetadata on STARTING
        if (state == Bundle.STARTING) {
            String servletName = metadata.getServletName();
            try {
                log.info("Publish HttpMetadata: " + metadata);

                // Load the endpoint servlet from the bundle
                Bundle bundle = context.getBundle();
                Class<?> servletClass = bundle.loadClass(servletName);
                HttpServlet servlet = (HttpServlet) servletClass.newInstance();

                ClassLoader ctxLoader = Thread.currentThread().getContextClassLoader();
                try {
                    // Register the servlet with the HttpService
                    HttpService httpService = getHttpService(context, true);
                    httpService.registerServlet("/example-interceptor/servlet", servlet, null, null);
                } finally {
                    // [AS7-903] 3rd party code may leak TCCL
                    Thread.currentThread().setContextClassLoader(ctxLoader);
                }
            } catch (RuntimeException rte) {
                throw rte;
            } catch (Exception ex) {
                throw new LifecycleInterceptorException("Cannot publish: " + servletName, ex);
            }
        }

        // Unregister the endpoint on STOPPING
        else if (state == Bundle.STOPPING) {
            log.info("Unpublish HttpMetadata: " + metadata);
            ClassLoader ctxLoader = Thread.currentThread().getContextClassLoader();
            try {
                HttpService httpService = getHttpService(context, false);
                if (httpService != null)
                    httpService.unregister("/example-interceptor/servlet");
            } finally {
                // [AS7-903] 3rd party code may leak TCCL
                Thread.currentThread().setContextClassLoader(ctxLoader);
            }
        }
    }

    private HttpService getHttpService(InvocationContext context, boolean required) {
        BundleContext bndContext = context.getBundle().getBundleContext();
        ServiceReference<HttpService> sref = bndContext.getServiceReference(HttpService.class);
        if (sref == null && required == true)
            throw new IllegalStateException("Required HttpService not available");

        HttpService httpService = bndContext.getService(sref);
        return httpService;
    }
}