com.fatwire.gst.web.status.StatusRequestListener.java Source code

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Here is the source code for com.fatwire.gst.web.status.StatusRequestListener.java

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/*
 * Copyright (C) 2006 Dolf Dijkstra
 *
 * 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.
 */
package com.fatwire.gst.web.status;

import java.lang.management.ManagementFactory;

import javax.management.ObjectName;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.ServletRequestEvent;
import javax.servlet.ServletRequestListener;
import javax.servlet.http.HttpServletRequest;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.fatwire.gst.web.status.jmx.StatusCounter;

/**
 * ServletRequestListener that signals the {@link RequestCounter} when requests start and end. Registers the
 * {@link StatusCounter} as a JMX MBean.
 * 
 * @author Dolf.Dijkstra
 * @since Jun 10, 2010
 */

public class StatusRequestListener implements ServletRequestListener, ServletContextListener {

    private Log log = LogFactory.getLog(StatusRequestListener.class);

    private RequestCounter requestCounter;

    private ObjectName name;

    public void requestDestroyed(ServletRequestEvent event) {
        if (event.getServletRequest() instanceof HttpServletRequest)
            try {
                requestCounter.end((HttpServletRequest) event.getServletRequest());
            } catch (Throwable e) {
                log.warn(e.getMessage(), e);
            }

    }

    public void requestInitialized(ServletRequestEvent event) {
        if (event.getServletRequest() instanceof HttpServletRequest)
            try {
                requestCounter.start((HttpServletRequest) event.getServletRequest());
            } catch (Throwable e) {
                log.warn(e.getMessage(), e);
            }

    }

    public void contextDestroyed(ServletContextEvent sce) {
        ConcurrencyCounterLocator.getInstance().deregister(requestCounter);
        requestCounter = null;
        try {
            ManagementFactory.getPlatformMBeanServer().unregisterMBean(name);
        } catch (Throwable e) {
            log.info(e.getMessage(), e);
        }

    }

    public void contextInitialized(ServletContextEvent sce) {
        String n = sce.getServletContext().getContextPath();
        if (n == null || n.length() == 0) {
            n = "/";
        }

        requestCounter = new RequestCounter(n);
        ConcurrencyCounter<?, ?> old = ConcurrencyCounterLocator.getInstance().register(requestCounter);
        if (old != null) {
            requestCounter = (RequestCounter) old;
        }
        try {
            name = new ObjectName("com.fatwire.gst.web:type=RequestCounter,name=" + ObjectName.quote(n));
            ManagementFactory.getPlatformMBeanServer().registerMBean(new StatusCounter(requestCounter), name);
        } catch (Throwable e) {
            log.warn(e.getMessage(), e);
        }

    }
}