Tomcat example source code file (MapperListener.java)

This example Tomcat source code file (MapperListener.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

error, exception, exception, host, iterator, management, mbeanservernotification, objectinstance, objectinstance, objectname, objectname, string, string, throwable, util, webmodule

The Tomcat MapperListener.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.catalina.connector;

import java.util.Iterator;
import java.util.Set;

import javax.management.MBeanServer;
import javax.management.MBeanServerNotification;
import javax.management.Notification;
import javax.management.NotificationListener;
import javax.management.ObjectInstance;
import javax.management.ObjectName;

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


import org.apache.tomcat.util.http.mapper.Mapper;
import org.apache.tomcat.util.modeler.Registry;

import org.apache.tomcat.util.res.StringManager;


/**
 * Mapper listener.
 *
 * @author Remy Maucherat
 * @author Costin Manolache
 */
public class MapperListener
    implements NotificationListener 
 {
    private static Log log = LogFactory.getLog(MapperListener.class);


    // ----------------------------------------------------- Instance Variables
    /**
     * Associated mapper.
     */
    protected Mapper mapper = null;

    /**
     * MBean server.
     */
    protected MBeanServer mBeanServer = null;


    /**
     * The string manager for this package.
     */
    private StringManager sm =
        StringManager.getManager(Constants.Package);

    // It should be null - and fail if not set
    private String domain="*";
    private String engine="*";

    // ----------------------------------------------------------- Constructors


    /**
     * Create mapper listener.
     */
    public MapperListener(Mapper mapper) {
        this.mapper = mapper;
    }


    // --------------------------------------------------------- Public Methods

    public String getDomain() {
        return domain;
    }

    public void setDomain(String domain) {
        this.domain = domain;
    }

    public String getEngine() {
        return engine;
    }

    public void setEngine(String engine) {
        this.engine = engine;
    }

    /**
     * Initialize associated mapper.
     */
    public void init() {

        try {

            mBeanServer = Registry.getRegistry(null, null).getMBeanServer();

            registerEngine();

            // Query hosts
            String onStr = domain + ":type=Host,*";
            ObjectName objectName = new ObjectName(onStr);
            Set set = mBeanServer.queryMBeans(objectName, null);
            Iterator iterator = set.iterator();
            while (iterator.hasNext()) {
                ObjectInstance oi = (ObjectInstance) iterator.next();
                registerHost(oi.getObjectName());
            }


            // Query contexts
            onStr = "*:j2eeType=WebModule,*";
            objectName = new ObjectName(onStr);
            set = mBeanServer.queryMBeans(objectName, null);
            iterator = set.iterator();
            while (iterator.hasNext()) {
                ObjectInstance oi = (ObjectInstance) iterator.next();
                registerContext(oi.getObjectName());
            }

            // Query wrappers
            onStr = "*:j2eeType=Servlet,*";
            objectName = new ObjectName(onStr);
            set = mBeanServer.queryMBeans(objectName, null);
            iterator = set.iterator();
            while (iterator.hasNext()) {
                ObjectInstance oi = (ObjectInstance) iterator.next();
                registerWrapper(oi.getObjectName());
            }

            onStr = "JMImplementation:type=MBeanServerDelegate";
            objectName = new ObjectName(onStr);
            mBeanServer.addNotificationListener(objectName, this, null, null);

        } catch (Exception e) {
            log.warn("Error registering contexts",e);
        }

    }

    /**
     * unregister this from JMImplementation:type=MBeanServerDelegate
     */
    public void destroy() {
        try {

            ObjectName objectName = new ObjectName(
                    "JMImplementation:type=MBeanServerDelegate");
            mBeanServer.removeNotificationListener(objectName, this);
        } catch (Exception e) {
            log.warn("Error unregistering MBeanServerDelegate", e);
        }
    }

    // ------------------------------------------- NotificationListener Methods


    public void handleNotification(Notification notification,
                                   java.lang.Object handback) {

        if (notification instanceof MBeanServerNotification) {
            ObjectName objectName = 
                ((MBeanServerNotification) notification).getMBeanName();
            String j2eeType = objectName.getKeyProperty("j2eeType");
            String engineName = null;
            if (j2eeType != null) {
                if ((j2eeType.equals("WebModule")) || 
                    (j2eeType.equals("Servlet"))) {
                    if (mBeanServer.isRegistered(objectName)) {
                        try {
                            engineName = (String)
                                mBeanServer.getAttribute(objectName, "engineName");
                        } catch (Exception e) {
                            // Ignore  
                        }
                    }
                }
            }

            // At deployment time, engineName is always = null.
            if ( (!"*".equals(domain)) &&
                 ( !domain.equals(objectName.getDomain()) ) &&
                 ( (!domain.equals(engineName) ) &&
                   (engineName != null) ) )  {
                return;
            }
            if(log.isDebugEnabled())
                log.debug( "Handle " + objectName  + " type : " + notification.getType());    
            if (notification.getType().equals
                (MBeanServerNotification.REGISTRATION_NOTIFICATION)) {
                String type=objectName.getKeyProperty("type");
                if( "Host".equals( type ) && domain.equals(objectName.getDomain())) {
                    try {
                        registerHost(objectName);
                    } catch (Exception e) {
                        log.warn("Error registering Host " + objectName, e);  
                    }
                }
    
                if (j2eeType != null) {
                    if (j2eeType.equals("WebModule")) {
                        try {
                            registerContext(objectName);
                        } catch (Throwable t) {
                            log.warn("Error registering Context " + objectName,t);
                        }
                    } else if (j2eeType.equals("Servlet")) {
                        try {
                            registerWrapper(objectName);
                        } catch (Throwable t) {
                            log.warn("Error registering Wrapper " + objectName,t);
                        }
                    }
                }
            } else if (notification.getType().equals
                       (MBeanServerNotification.UNREGISTRATION_NOTIFICATION)) {
                String type=objectName.getKeyProperty("type");
                if( "Host".equals( type )&& domain.equals(objectName.getDomain())) {
                    try {
                        unregisterHost(objectName);
                    } catch (Exception e) {
                        log.warn("Error unregistering Host " + objectName,e);  
                    }
                }
 
                if (j2eeType != null) {
                    if (j2eeType.equals("WebModule")) {
                        try {
                            unregisterContext(objectName);
                        } catch (Throwable t) {
                            log.warn("Error unregistering webapp " + objectName,t);
                        }
                    }
                }
            }
        }

    }


    // ------------------------------------------------------ Protected Methods

    private void registerEngine()
        throws Exception
    {
        ObjectName engineName = new ObjectName
            (domain + ":type=Engine");
        if ( ! mBeanServer.isRegistered(engineName)) return;
        String defaultHost = 
            (String) mBeanServer.getAttribute(engineName, "defaultHost");
        ObjectName hostName = new ObjectName
            (domain + ":type=Host," + "host=" + defaultHost);
        if (!mBeanServer.isRegistered(hostName)) {

            // Get the hosts' list
            String onStr = domain + ":type=Host,*";
            ObjectName objectName = new ObjectName(onStr);
            Set set = mBeanServer.queryMBeans(objectName, null);
            Iterator iterator = set.iterator();
            String[] aliases;
            boolean isRegisteredWithAlias = false;
            
            while (iterator.hasNext()) {

                if (isRegisteredWithAlias) break;
            
                ObjectInstance oi = (ObjectInstance) iterator.next();
                hostName = oi.getObjectName();
                aliases = (String[])
                    mBeanServer.invoke(hostName, "findAliases", null, null);

                for (int i=0; i < aliases.length; i++){
                    if (aliases[i].equalsIgnoreCase(defaultHost)){
                        isRegisteredWithAlias = true;
                        break;
                    }
                }
            }
            
            if (!isRegisteredWithAlias && log.isWarnEnabled())
                log.warn(sm.getString("mapperListener.unknownDefaultHost", defaultHost));
        }
        // This should probablt be called later 
        if( defaultHost != null ) {
            mapper.setDefaultHostName(defaultHost);
        }
    }

    /**
     * Register host.
     */
    private void registerHost(ObjectName objectName)
        throws Exception {
        String name=objectName.getKeyProperty("host");
        if( name != null ) {        
            String[] aliases = (String[])
                mBeanServer.invoke(objectName, "findAliases", null, null);
            mapper.addHost(name, aliases, objectName);
            if(log.isDebugEnabled())
                log.debug(sm.getString
                     ("mapperListener.registerHost", name, domain));

        }
    }


    /**
     * Unregister host.
     */
    private void unregisterHost(ObjectName objectName)
        throws Exception {
        String name=objectName.getKeyProperty("host");
        mapper.removeHost(name);
        if(log.isDebugEnabled())
            log.debug(sm.getString
                 ("mapperListener.unregisterHost", name, domain));
    }


    /**
     * Register context.
     */
    private void registerContext(ObjectName objectName)
        throws Exception {

        String name = objectName.getKeyProperty("name");
        
        // If the domain is the same with ours or the engine 
        // name attribute is the same... - then it's ours
        String targetDomain=objectName.getDomain();
        if( ! domain.equals( targetDomain )) {
            try {
                targetDomain = (String) mBeanServer.getAttribute
                    (objectName, "engineName");
            } catch (Exception e) {
                // Ignore
            }
            if( ! domain.equals( targetDomain )) {
                // not ours
                return;
            }
        }

        String hostName = null;
        String contextName = null;
        if (name.startsWith("//")) {
            name = name.substring(2);
        }
        int slash = name.indexOf("/");
        if (slash != -1) {
            hostName = name.substring(0, slash);
            contextName = name.substring(slash);
        } else {
            return;
        }
        // Special case for the root context
        if (contextName.equals("/")) {
            contextName = "";
        }

        if(log.isDebugEnabled())
             log.debug(sm.getString
                  ("mapperListener.registerContext", contextName));

        Object context = 
            mBeanServer.invoke(objectName, "findMappingObject", null, null);
            //mBeanServer.getAttribute(objectName, "mappingObject");
        javax.naming.Context resources = (javax.naming.Context)
            mBeanServer.invoke(objectName, "findStaticResources", null, null);
            //mBeanServer.getAttribute(objectName, "staticResources");
        String[] welcomeFiles = (String[])
            mBeanServer.getAttribute(objectName, "welcomeFiles");

        mapper.addContext(hostName, contextName, context, 
                          welcomeFiles, resources);

    }


    /**
     * Unregister context.
     */
    private void unregisterContext(ObjectName objectName)
        throws Exception {

        String name = objectName.getKeyProperty("name");

        // If the domain is the same with ours or the engine 
        // name attribute is the same... - then it's ours
        String targetDomain=objectName.getDomain();
        if( ! domain.equals( targetDomain )) {
            try {
                targetDomain = (String) mBeanServer.getAttribute
                    (objectName, "engineName");
            } catch (Exception e) {
                // Ignore
            }
            if( ! domain.equals( targetDomain )) {
                // not ours
                return;
            }
        }

        String hostName = null;
        String contextName = null;
        if (name.startsWith("//")) {
            name = name.substring(2);
        }
        int slash = name.indexOf("/");
        if (slash != -1) {
            hostName = name.substring(0, slash);
            contextName = name.substring(slash);
        } else {
            return;
        }
        // Special case for the root context
        if (contextName.equals("/")) {
            contextName = "";
        }
        if(log.isDebugEnabled())
            log.debug(sm.getString
                  ("mapperListener.unregisterContext", contextName));

        mapper.removeContext(hostName, contextName);

    }


    /**
     * Register wrapper.
     */
    private void registerWrapper(ObjectName objectName)
        throws Exception {
    
        // If the domain is the same with ours or the engine 
        // name attribute is the same... - then it's ours
        String targetDomain=objectName.getDomain();
        if( ! domain.equals( targetDomain )) {
            try {
                targetDomain=(String) mBeanServer.getAttribute(objectName, "engineName");
            } catch (Exception e) {
                // Ignore
            }
            if( ! domain.equals( targetDomain )) {
                // not ours
                return;
            }
            
        }

        String wrapperName = objectName.getKeyProperty("name");
        String name = objectName.getKeyProperty("WebModule");

        String hostName = null;
        String contextName = null;
        if (name.startsWith("//")) {
            name = name.substring(2);
        }
        int slash = name.indexOf("/");
        if (slash != -1) {
            hostName = name.substring(0, slash);
            contextName = name.substring(slash);
        } else {
            return;
        }
        // Special case for the root context
        if (contextName.equals("/")) {
            contextName = "";
        }
        if(log.isDebugEnabled())
            log.debug(sm.getString
                  ("mapperListener.registerWrapper", 
                   wrapperName, contextName));

        String[] mappings = (String[])
            mBeanServer.invoke(objectName, "findMappings", null, null);
        Object wrapper = 
            mBeanServer.invoke(objectName, "findMappingObject", null, null);

        for (int i = 0; i < mappings.length; i++) {
            boolean jspWildCard = (wrapperName.equals("jsp")
                                   && mappings[i].endsWith("/*"));
            mapper.addWrapper(hostName, contextName, mappings[i], wrapper,
                              jspWildCard);
        }

    }




}